Artificial Eye (Ocular Prosthesis)
By Chandrashekhar Chawan
1 HISTORY
Since ancient times Artificial Eyes have been used to escape the terror
of stigmatisation due to Ocular Disfigurement. The Artificial Eyes used to
be made of gold and precious stones.
In India there are references to artificial eye or eye transplant, dating
back to 5600 BC from Shalivahan Shaka Parva in the book called
“Garbhopanishad” written by Shri Garbbhacharya in 2 BC. One can find
references to artificial eyes and eye transplants.
In Takshashila region during Shri Chanakyas time one Nilakumari
mentions in her book called “Neelavati” an operation which she
performed on an 8 year old girl who had lost her eye due to penetrating
injury.
In 444 AD in Nalanda Vidyapith Shri Nagarjunbharda was in-charge of
Human Medicine and Animal Medicine and used to perform eye surgery.
In 632 AD Shri Charak, Shri Shushrut and Shri Vagbhat were among the
leading cosmetic surgeons who performed many operations on humans
to cure disfigurement.
King Shashankdev of Vikramshila region has awarded an eye made of
gold as a trophy to Acharya Prashastpad , in 633 AD, for his work in eye
surgery on patients who had lost their eyes due to small pox.
Goat’s eyes wrapped in some ‘keratin’ substance and implanted in the
eye socket gave the effect of a natural eye; however this type of
cosmetic eye is smaller than the natural human eye. This is referred to in
the book “Sughatan Shalyachikitsa”.
The Vikramshila Dynasty was destroyed in 1210 AD by the Moguls and
all the knowledge and most of the books written on “Tadapatra” (large
tree leaves dried and cured) were burnt by the Mogul invaders.
Since 1446 Portuguese Doctors introduced their system of medicine.
From 1670 the British introduced the Greek Medicine which is followed
to this day.
Technical developments, in the 18th and 19th centuries, in medicines and
medical technologies accelerated the general developments.
It is an interesting thought that, if the best of all the medical systems
available today, were to be integrated to develop a single system, for the
betterment of the human society.
Ludwig Muller, a glass blower, used to make doll’s eyes, developed
cryolite glass eyes. The breakage problems of glass led to the
development of new materials.
Germany was the major supplier of glass eyes. During world II, the glass
eye supply became scarce and technologist started experimenting with
plastics.
Now all over the world Artificial Eyes are made of PMMA (poly methyl
methacrylate) and only in some parts of Europe and Germany glass
eyes are still manufactured.
PMMA is found to be biocompatible material, is non-allergic and gives
life like effect to artificial eyes.
Readymade artificial eyes are made in large quantities to stock and are
available in the market since 40-50 years. Though they are cheap and
easily available they cannot be fitted to all, certainly not to special cases,
and if fitted present problems such as excessive eye discharge, poor
comfort, poor cosmetic matching, restricted wearing periods and
reduced translate ocular movement. In the long run they cause sagging
of the lower lid and in some cases contracted eye socket.
Depending on the chain of polymers the quality of PMMA is determined.
A simple acryl ate is brittle and breaks easily. Whereas, High Density
Medical Grade PMMA is very useful for making an artificial eye.
The stock eyes available in the market today are made from low-grade
plastic. Hence they become discoloured and develop cracks after a few
years and need frequent replacements.
For making Custom made artificial eyes a High-Density Medical Grade
PMMA is used, in order to overcome all the problems of simple acrylic. It
is not only tough but also very clear like glass, hence gives a more
natural look to the Artificial Eye.
As the art and science of Ocular Prosthesis is making progress all over
the world, people are becoming aware of the advantages of custom
made artificial eye, and are using them for cosmetic rehabilitation. The
role of the “stock eye” is becoming limited around the world and they are
used as a “stop gap” arrangement initially, till a “Custom Made Artificial
Eye” is prepared.
I India and other developing countries large number of patients have to
depend on stock eye as the number of Ocularists fitting custom made
artificial eye is limited.
2 ANATOMY AND PHYSIOLOGY OF THE EYE
The sense of vision is based on a step-wise process in which rays of
light are focused on the Retina, where it is converted in to an electrical
signal and is conveyed through the visual pathways to the brains
occipital cortex. This signal is interpreted as a visual message by the
brain. If any part of the system is affected by a disease, vision may be
impaired.
As an Ocularist one should know the parts of the eye, its surrounding
tissues, and its connections in the brain. As each part is described, you
will know its structure (anatomy), function (physiology) and how it can
become diseased (pathology).
The Ocular Adnexa (Fig. 1.1)
Ocular adnexa is the tissue surrounding the eye, it protects and
preserves the normal function of the eyes. The Ocular Adnexa include:
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Eyelids and Conjunctiva
Lacrimal apparatus
Orbit
Extraocular muscles
The Eyelids and Conjunctiva
The eyelids are moving folds of soft tissue that protect the outer portion
of the eyeball from injury, exclude light and lubricate the front surface of
the eye.
The blinking action of the upper lid spreads lubricating tear film over the
front surface of the eye.
The elliptical opening between the upper and the lower lids is called the
“Palpebral Fissure”. The normal size of the palpebral fissure is about 15
mm when the lids are open.
The inner junction of the lids is called the “Medial Canthus” and the outer
junction is called the “Lateral Canthus”. The medial canthus contains
folds of fleshy tissue. The deeper one is called the “Plica Semilunaris”
(semi-lunar fold) and the more visible one is the “Caruncle” . The medial
lid margins of the upper and lower lids contain small openings to the tear
drainage system that is called the “Puncta”.
The anterior edge of the lid margins contains the hair follicles for the
eyelashes (cilia). The lashes serve to sweep airborne particles away
from the eye during a blink. Oil secreting glands called “Meibomian
Glands” are situated on the posterior edge of the lid margin. Just in front
of these glands is the grey line, which divides the inner (close to the
eye), and outer portions of the lid margin.
Acute inflammation of a lash follicle is called a “Stye” (hordeolum exter
num). It is a reddened, sore lump near the lid margin. Further from the
lid margin, chronic inflammation may involve a meibomian gland
producing a chalazion.
Blepharitis is the term applied to diffuse inflammation of the lid margin,
which is usually the result of an overgrowth of the normal bacterial
population of the lid. Patients with Blepharitis have reddened, crusted lid
margins usually covering the entire extent of the lid.
The eyelids are composed of an outer layer of skin, an inner layer of
palpebral conjunctiva and a layer of fibrous tissue and muscle between
the two. The fibrous layer, called the “Tarsal Plate”, gives the lid its
firmness. The orbicularis oculi is circular muscle that, upon contraction,
results in forced eyelid closure, as in winking. The upper lid is raised by
the levator plpebral superioris muscle, which attaches to the upper tarsal
plate. The muscle is part of a group of extraocular muscels those are
controlled by the third cranial (oculomotor) nerve.
Instead of lying in its normal position against the eyeball, the lid margin
may turn away from or towards the globe. This turning out of the margin
is called “Ectropion” and may lead to drying and irritation of the exposed
cornea and conjunctiva.
An inward turning of the lid margin is called “Entropion”, in this condition,
eye lashes may rub against the cornea and cause irritation and tearing,
Inward turning of eye lashes is known as “Trichiasis”.
Loss of function of the levator muscle results in “Ptosis” a droopy upper
eyelid that no longer elevates normally.
Diseases which affect the skin elsewhere on the body, may affect the
skin of the lids. Careful examination may reveal dermatitis, cysts or
tumours (especially basal cell carcinomas).
The conjunctiva is the translucent mucous membrane that lines the inner
surface of the lids (the palpebral portion of the conjunctiva).
The bulbar conjunctiva ends at the limbus. The junction of the bulbar
conjunctiva and the palpebral conjunctiva is called the “Fornix” or “Culde-Sac”.
The conjunctiva may become inflamed, due to bacterial or viral infection
or because of an allergic reaction, is called “Conjunctivitis”, it is
sometimes called “Red-Eye”, produces enlargement of surface blood
vessels, causing the normally white part of the eye, the “Sclera”, to
appear red. Sometimes, a blood vessel may rapture spontaneously and
allow blood to flow under the conjunctiva. This is referred to as a
“Subconjunctival haemorrhage and usually resolves in a few weeks
without any treatment. Most often this haemorrhage occurs without
explanation or after violent s sneezing or coughing, but rarely it may be
associated with high blood pressure or bleeding disorders. A
pingueculum, a yellowish mass on the bulbar conjunctiva just nasal or
temporal to the limbus, probably represents irritation from sunlight.
Continued irritation, especially by exposure to intense sunlight, may lead
to formation of a pterygium, a fleshy wedge of bulbar conjunctiva that
grows from the canthus (usually medial) towards the cornea. It may
cause some irritation, but is not harmful unless it grows over the central
cornea and impairs vision. If this happens, it must be surgically removed.
Lacrimal Apparatus (Fig. 1.2)
The lacrimal apparatus is composed of tear-producing glands and a tear
drainage system. The lacrimal gland secretes the aqueous portion of
tears and is located in the lateral segment of the upper lid just under the
upper orbital rim. There are small, accessory lacrimal glands scattered
throughout the upper fornix. The tear fluid is spread over the front
surface of the eye when the upper lid closes during a blink. Tears then
form a pool along both lid margins before passing through the upper and
lower puncta (holes) into the canaliculi (little canals) of the drainage
system. The upper and lower canaliculi merge into the common
canliculus near the medial canthus, and the tears then flow into the
lacrimal sac. The sac empties into the nasal cavity by means of the
nasolacrimal duct. Where hot air being breathed out evaporates these
tears.
The tear film is composed of three layers. The meibomian glands
secrete the outer, oily layer, which helps prevent evaporation of the
tears. The middle, aqueous (water) layer, secreted by the lacrimal gland,
contains the oxygen and nutrients that nourish the cornea. The inner,
mucinous layer is secreted by the goblet cells of the conjunctiva. The
mucinous layer helps to maintain an even spread of tears over the
cornea. The lacrimal system produces up to 1 ml (about 1/4th teaspoon)
of tears during the waking hours, about 50% of which are lost to
evaporation. No tears are produced during sleep. The tear-producing
lacrimal gland is generally free of disease, but occasionally inflammation
or tumours may occur in it. On the other hand, inflammation of the tearcollecting lacrimal sac, dacryocystits is relatively common. It usually
occurs as a result of obstruction of the nasolacrimal duct. In infants, this
obstruction is commonly the result of a congenital narrowing of the
nasolacrimal duct where it opens into the nasal cavity. This often opens
with time, if it does not it may require probing or other treatment. The
signs of dacryocystitis are tenderness and swelling below the inner
canthus, discharge or excessive tearing (epiphora). In the adult,
obstruction of the tear outflow system occurs as a result of chronic
lacrimal sac infection, facial trauma or tumours. If the blockage is
severe, it may be necessary to bypass the nasolacrimal duct by
surgically fashioning an opening between the sac and the nose (is
called”Dacryocystorhinostomy”). Older persons and persons certain
systemic diseases, may be subject to dry eyes (keratitis sicca). When
one or more of the tear film components is insufficient, the tears cannot
function properly and cornea becomes irritated. Patients usually treated
with artificial tears.
Orbit
The orbit is the cavity in the skull, which houses the eyeball. Its walls
consist of seven bones, and it contains the eyeball, the extraocular
muscles, blood vessels and nerves cushioned by a great deal of fat.
Four of the muscles form the muscle cone within the orbit through which
pass the optic nerve and most of the blood vessels and nerves to the
eye. The muscle cone originates in the posterior orbit as a circle of
muscles called “Annulus of Zinn”.
Since the back of the orbit narrows, any increase in the orbital volume
will cause the eyeball to protrude; this condition is called “Proptosis or
Exophthalmos”. Proptosis is often seen in association with Graves’
disease, a condition of unknown cause that affects both the thyroid
gland and the soft tissues around the eyes. Other causes include
tumours, inflammation (including infection) or haemorrhage.
Diffuse infection of orbital tissue or orbital cellulitis, appears as grossly
swollen lids, a red eye and sometimes proptosis. When the tissue bulk in
the orbit is greater than normal, the eye muscles may not be free to
move normally. If the eyes go out of alignment (strabismus), the patient
may complain of double vision (diplopia). Misalignment of the eyes also
results when one (or more) of the eye muscles become restricted in its
movement because it has become inelastic from scarring or trapped by
broken orbital bones. Muscle scarring occurs after any long-term
inflammation, but the most common cause is Graves’ disease.
Extraocular Muscles (Fig. 1.3)
The eyeball is moved by the action of six extraocular muscles. The
medial rectus pulls the eye towards the nose in adduction and inserts on
the globe 5.5 mm from the medial limbus. The lateral rectus moves the
eye away from the nose in abduction and inserts about 7 mm from the
lateral limbus. The eye is elevated primarily by the superior rectus
(insertion at 8 mm) and depressed primarily by the inferior rectus
(insertion at 6 mm). The oblique muscles insert behind the equator of the
globe and assist in elevation (inferior oblique) and depression (superior
oblique).
The superior oblique also intorts the eye and the inferior extorts the eye.
To understand intorsion and extorsion, imagine that the eye rotates on a
pole piercing it from front to back. Intorsion means clockwise rotation of
the right eye, counter-clockwise rotation of the left eye; extortion is
rotation in the opposite direction.
The function of the six extraocular muscles are evaluated by asking the
patient to move his eyes from straight ahead gaze, i.e. primary position
in to upward gaze, downward gaze and into the six cardinal positions of
gaze, which are right gaze, left gaze, up and right gaze, down and right
gaze, up and left gaze, down and left gaze. The movement of the two
eyes into this diagnostic gaze positions are called “Versions”.
The Eye
The main components of the eye are the
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Cornea
Sclera
Anterior chamber
Uveal tract
Pupil
Lens
 Vitreous
 Retina
 Optic disc
Cornea
The cornea is the transparent anterior structure of the globe. Its
transparency results from a highly ordered cell structure and low water
content. The cornea loses its transparency if either of these factors is
altered.
There are five layers of the corneal tissue, but the outermost and
innermost layers are most important. The outermost layer is called the
“Epithelium” which consists of cells that are constantly regenerating.
A superficial injury to this layer, by a contact lens or small foreign bodies,
will usually heal within 24 to 48 hours. But infections with viruses,
bacteria or fungi will require vigorous medical treatment. The innermost
layer, the “Endothelium”, prevents the intraocular fluid from penetrating
the cornea. If disease or trauma has damaged the endothelial cells, they
may no longer be able to regulate the amount of water that reaches the
internal tissue of the cornea. When this occurs, the cornea swells and
becomes cloudy, this condition is called “Edema”.
Situated between the outermost epithelium and the innermost
endothelium are three layers, called “Bowman’s Membrane”, the
“Stroma” and “Descemet’s Membrane”. They each add rigidity to the
cornea and provide additional barriers to infection.
The front surface of the cornea focuses light rays and contributes about
two-thirds of the optical power of the eye. Because it must remain clear,
the cornea contains no blood vessels. The cells are nourished by the
aqueous humour and by the tear film, which also serves to maintain a
smooth optical surface. The cornea is about 11.5 mm in diameter and
0.5 mm thick at its centre. Its junction with the sclera is called the
“Limbus”. The limbus is also the location of the attachment of the bulbar
conjunctiva to the globe. Tiny conjunctival capillaries at the limbus
supply nutrients to the peripheral cornea.
Corneal inflammation is referred to as “Keratitis” and may result from a
great variety of conditions such as a tear deficiency, toxic chemicals or
infections. With any keratitis the patient usually experiences a foreign
body sensation, eye pain aggravated by bright light, the condition called
”Photophobia”, blurred vision, redness and excessive tearing. In severe
cases of keratitis, the anterior corneal tissue is destroyed and a corneal
ulcer develops. Bacterial ulcers may be mild or severe, but the reaction
to them is striking. The bulbar conjunctiva, which covers the white of the
eye, becomes quite red, and there is often a copious discharge from the
eye.
The active ulcer produces an opaque area on the cornea. As it heals, it
leaves a scar that may result in permanently decreased vision. The
surface of the ulcer must be scraped and cultured in order to discover
the specific causative organism, which is treated with the appropriate
antibiotic. Fungi may also cause corneal ulcers, usually as a result of a
corneal injury with some type of vegetable matter (thorns, branches,
pieces of wood). Without adequate treatment, the ulcers may extend
through the cornea and cause infection inside the globe.
Herpes simplex keratitis caused by the virus responsible for “cold sores”
produces branch-like (“dendritic”) erosion of the corneal epithelium that
may progress to form an ulcer. Symptoms of an early infection are often
mild, but careful examination reveals that the eye is red and watery. This
ulcer must be treated promptly with special anti-viral drugs to prevent
spreading to deeper corneal tissues. Once the disease has spread
beneath the epithelium, the scar that remains after the healing process
may seriously impair vision and leave a total corneal opacity, which may
require corneal transplant surgery.
Corneal dystrophies are hereditary defects in the structure of cornea due
to which the cornea loses its clarity. Corneal dystrophies become
apparent at all ages. One example is keratoconus, in which the central
cornea becomes thin and cone-shaped. The increase in corneal
curvature at the centre of the cone causes an increasing
nearsightedness (myopia) and astigmatism. The process begins in the
teenage years and is usually completed by the late twenties. The
decreased vision may be corrected in early stages by Rigid Gas
Permeable Contact Lenses, but corneal thinning may become severe
enough to require a corneal transplant.
A common change in the cornea of older patients is an opaque ring,
called “Arcus Senilis”, seen near the limbus. It represents deposition of
fatty substances from the blood. While it causes no symptoms, it may be
a signal of an abnormally high fat content of the blood.
Sclera
The sclera, the white of the eye, is the rigid outer portion of the wall of
the eye that protects and supports the delicate inner structures. The
sclera meets the cornea at the limbus. Occasionally the sclera or
overlaying episcleral tissue becomes inflamed (scleritis and episcleritis)
and may require treatment. Patients with rheumatoid arthritis may
develop areas of marked sclera thinning (scleromalacia) which allows
the purple colour of the underlying choroid to show through.
Anterior Chamber
The anterior chamber is the space between the back of the cornea and
the front of the iris. It is filled with clear aqueous fluid humour produced
by the ciliary body lying behind the iris.
The aqueous fluid is secreted by the processes of the ciliary body and
flows through the pupil into the anterior chamber. It exits from the eye at
the junction of the cornea and the iris, where it flows through a filter
called the “Trabecular Meshwork” and into the canal of “Schlemm”.
From here it empties into episcleral veins.
The balance between aqueous production and drainage normally
maintains the intraocular pressure between 12 and 20 mm Hg (mercury).
If aqueous drainage is impaired, the intraocular pressure rises and may
cause optic nerve damage and loss of vision, this condition is called
“Glaucoma”.
Inflammation or infection within the eye may cause a pool of pus
(hypopyon) to layer out at the bottom of the anterior chamber. When
blood is found in the anterior chamber, after an injury or in certain
diseases, it is called “Hyphema”.
Uvea
The uvea or “uveal tract” is the middle layer of the wall of the eye and is
composed of the iris, the ciliary body and the choroid. The iris is the
coloured part of the eye that controls the size of the central opening, the
“Pupil”. The front layers of the iris contain its blood supply, muscles and
pigment. The dialator muscle, which extends radially from the iris root to
the pupil margin, opens the pupil (mydriasis) when it contracts.
The sphincter muscle encircles the pupil margin and makes the pupil
smaller (miosis) when it contracts. A blue iris contains a relatively small
amount of pigment while brown iris contains a relatively large amount.
Pigment is deposited in the iris as the nervous system is developing.
Because some of this development occurs after birth, most newborn
babies have light eyes. Since the appearance of the net of new blood
vessels on the iris gives it reddish cast, it is called “Rubeosis. Rubeosis
may be responsible for blood leakage into the anterior chamber or
obstruction of the filtration angle. Several diseases (especially diabetes)
may cause an abnormal growth of new blood vessels
(neovascularisation) on the surface of the iris. The iris may also be the
site of nevi (freckles), tumours, cysts or nodules. The ciliary body is a
band-like structure of muscle and secretory tissue that encircles the
inside of the eye from behind the root of the iris to the anterior edge of
the retina (the ora serrata). Most of the function of the ciliary body is
concentrated in the anterior part, a folded muscle mass called the “Pars
Pilicata”, which is composed of finger like ciliary processes that are
responsible for secretion of the aqueous fluid. The posterior portion of
the ciliary body is flat and is called the “Pars Plana. This latter area is a
frequent site for surgical entry into the back of the eye because it
contains relatively few delicate structures. Some of the muscle fibers of
the ciliary body are arranged in a circular fashion and these control the
eye’s ability to focus on near objects (the phenomenon is called
“accommodation”).
The ciliary body may become inflamed in diseases that affect the iris and
choroid as well (uveitis), it may also give rise to tumours or cysts.
The choroid is the posterior portion of the uveal tract. It is largely
composed of blood vessels and lies between the sclera and the retina. It
provides the blood supply for the outer cells of the retina. Inflammation
of the choroid (choroiditis, posterior uveitis), may result from infection or
from unknown (idiopathic) causes. The choroid may be the site of
tumours such as malignant melanoma or metastatic cancer. Malignant
melanoma is recognised as an elevated pigmented lesion that may
cause the retina to detach. It is important to diagnose malignant
melanomas early, so they can be treated before they spread to the rest
of the body and cause death.
Pupil
The pupil is the central opening in the iris that regulates the amount of
light reaching the retina. The size of the pupil is controlled by the
sphincter and dilator muscles of the iris. Each of these muscles is
governed by a different part of the autonomic nervous system.
The sympathetic system controls the dilator muscle that opens the pupil
and the parasympathetic system controls the sphincter muscle that
closes the pupil. Ordinarily the pupils are about 4 mm in diameter in a
dimly illuminated environment and equal in size in both eyes. It is not
unusual for the pupil sizes, in an individual, to differ, from o.5 to 1.0 mm.
When the two pupils of an individual differ in size by more than 1.0 mm
(anisocoria), there is an abnormality of one pupil or other (or both). If the
inequality is greater in dim illumination where the pupils usually larger,
then the dilator muscle is not working in the eye with the smaller pupil.
On the other hand, if the anisocoria is greater in bright light, when the
pupils are usually smaller, then the sphincter is not working in the eye
with the larger pupil. Once the weak muscle has been determined, the
part of the nervous system that is affected can be identified.
Lens
The crystalline lens is a normally transparent, biconvex structure that is
located in the posterior chamber between the iris and the vitreous body.
The lens is composed of an inner nucleus, a surrounding cortex and an
enveloping capsule.
The lens is responsible for about 1/3rd of the total focussing power of the
eye and accounts for the ability to change focus from distance to near
objects. The lens is suspended just behind the pupil by fibers called
“Zonules” that are attached to the ciliary processes. When the ciliary
muscles muscle contract, it relaxes the tension on the zonuls and allows
the lens to become more round. The increased curvature of the lens
makes it a more powerful refracting surface.
The process of ciliary muscle contraction and increased lens curvature is
called accommodation. The ability of the lens to change its shape
depends on its elasticity. As it ages, the lens tissue becomes
increasingly more rigid and accommodation power is gradually lost
(presbyopia). This is the reason that most people, as they age, have to
wear corrective bifocal spectacles; the lower segment helps the eye
focus on near objects.
When the lens proteins degenerate, the lens loses its transparency, this
is called a “Cataract”. Thus synonyms for cataract are lens opacification.
Cataracts may be present at birth, though this is rare. Most commonly,
cataracts occur as part of the normal aging process (senile cataract).
Lens opacities may also be the result of an injury to the eye or may be
associated with ocular or systemic disease or with chronic use of certain
drugs. When vision has become significantly impaired, the lens is
surgically removed. An eye with a lens in place is called “Phakic”. Once
the lens has been removed, the eye becomes “Aphakic”. When the eye’s
own lens has been removed, its refractive power must be replaced with
a powerful artificial lens, either as a spectacle, a contact lens or an
intraocular lens (implant).
Vitreous
The vitreous body is a clear, gelatinous mass that fills the intraocular
cavity behind the lens and helps maintain the spherical shape of the
globe. When small particles drift across the vitreous, patients report that
they see floaters. Floaters are a normal occurrence and need not be
investigated unless they suddenly increase in number, if so, they may
represent condensations of a portion of vitreous that has become
detached from the retina. This vitreous detachment occurs as a normal
part of aging, but may lead, in rare cases, to a retinal detachment, a
vision threatening emergency.
The vitreous material is an excellent culture medium for bacteria. When
infectious agents are accidentally introduced into the eye, either by injury
or surgery, their growth may be so rapid as to destroy an eye within
days. Infection of the vitreous and the adjacent tissue is called
“Endophthalmitis” and constitutes an emergency. The infection is treated
with large doses of antibiotics, but may also require the surgical removal
of the infected vitreous (vitrectomy).
Abnormal retinal blood vessels may produce a haemorrhage into the
vitreous that obscures vision. Usually this blood is absorbed over time.
However, if the blood or resulting fibrous tissue remains, the vitreous
may have to be removed surgically.
Retina
The retina is a transparent structure that lines the inner surface of the
globe posteriorly, and is actually an extension of the brain. It converts
light to electrical (nerve) impulses and transmits these impulses to the
brain’s visual cortex where they are integrated into the sensation of
sight. When viewed through an ophthalmoscope, the normal retina
appears orange, the retina though transparent, appears orange due to
the blood vessels of the underlying choroid. Lying on the inner surface of
the retina are the retinal arterioles (bright red) and veins (dark red).
The retina is composed of an inner sensory portion and an outer
pigment epithelium. The most important part of the sensory retina is the
photoreceptor layer. It contains two types of photoreceptor cells, the
cones and the rods, each with a different function in the visual process.
Cones provide sharp central vision (acuity) and colour vision and
function best in daylight. Rods are largely responsible for peripheral
vision and function even in dim illumination. The innermost part of the
retina consists of ganglion cells. Fibres from the ganglion cells for m the
nerve fibre layer of the retina that converges at the optic disc. A
specialised area of the retina containing most of the cone cells is located
lateral to the optic disc and is called the “Macula”. The centre of the
macula is called the “Fovea”. Damage to the macula will greatly reduce
visual acuity and the eye will be left with only peripheral vision. When
any other area of the retina is damaged, blind spots occur in off-centre
position of the visual field. During development of the embryo, a cleft
forms between the sensory and pigment epithelial portions of the retina
that, under certain circumstances, may lead to an actual separation of
these layers. Such a separation is called a “Retinal Detachment”.
Trauma inflammation, eye surgery or the natural aging process may
result in a tear in the sensory retina. Vitreous fluid leaks through the tear
and spreads under the sensory retina causing it to become detached
from the pigment epithelium. Patients who have a retinal detachment
notice floaters, light flashes, blurred vision and sometimes the sensation
of a “curtain” obscuring a portion of their field of vision. The detachment
must be repaired surgically as soon as possible to prevent irreparable
damage to sight.
Of the many disorders that affect the retina, senile macular degeneration
is probably the most common. It occurs in the elderly and produces a
slow decline in visual acuity usually in both eyes. The cause appears to
be poor choroidal blood supply. In this condition, abnormal blood vessels
(neovascularisation) that form beneath the macula leak and deform this
delicate structure. In some cases such neovascularisation may be
treated with the laser beam to prevent further vision loss.
A rare tumour called a “Retinoblastoma” can arise in the retina of very
young children. Because retinoblastoma is life threatening, the eye
containing this tumour is treated promptly, either by radiation or surgical
removal (enucleation).
Optic Disc
After passing through the transparent inner layers of the retina, light is
converted by the rods and cones to a nerve impulse that travels forward
to the ganglion cell layer and then to the optic disc by way of the nerve
fiber layer. The optic disc is situated in the nasal portion of the fundus,
15 degrees off-centre. Because no rods and cones are present in this
area, it is sightless and termed the physiologic blind spot in the field of
vision. Inflammation and stroke (blood vessel blockage) can damage the
optic disc and produce defects in any portion of the field of vision. When
the intracranial pressure is abnormally high, the disc tissue will swell
(papilledema). There are other causes of optic disc swelling, including
inflammations and strokes of the disc tissue itself. The optic disc tissue
becomes excavated (cupped) in advanced glaucoma.
Retrobulbar Visual Pathway (fig. 1.4)
The eye is only the first part of the visual pathway, which extends to the
back of the brain. The pathway that conducts visual messages after they
leave the eye is termed the retrobulbar visual pathway.
The nerve impulse triggered by light striking the retina exits from the eye
through the optic nerve, travelling to the optic chiasma. Here only the
nasal nerve fibres from each eye cross to the opposite side, while the
temporal fibres continue along on the same side. After the chiasma, the
temporal nerve fibres from one eye and the nasal fibres from the other
eye travel together in the optic tract and end in the lateral geniculate
body.
From there the impulse is carried via the optic radiations to the occipital
lobe in the posterior part of the brain. The destination of these fibres
within the occipital lobe is called the “Visual (calcarine) Cortex”, where
the visual message is integrated with information derived from other
parts of the brain in a process called “Perception”.
Disorders affecting other parts of the visual pathway produce
characteristic changes in the field of vision. The most common disorders
are tumours of the pituitary gland (which lies directly under the chiasma)
and strokes, aneurysms, inflammations, infections and trauma.
3 OCULAR TRAUMA
Permanent disfigurement can occur following ocular trauma. The
different types of ocular trauma are:
 Foreign body in the eye, that may leave permanent corneal
opacity,
 Chemical trauma can cause total corneal opacity and many
complications in the eye such as symblepharon, phthisical eye etc.
 Blunt trauma can lead to permanent loss of vision due to retinal
detachment and may further lead to pthisisbulbi.
 Penetrating injury in the eye can result in retinal tear, infection
leading to evisceration or enucleation of the eyeball.
 Blow out fracture of the orbit because of the accident can lead to
severe disfigurement.
 Surgical trauma means failure of surgical procedure on the table or
iatrogenic trauma due to post surgical infection can lead to
evisceration or enucleation of the eyeball.
4 REMOVAL OF AN EYE (enucleation)
When a Doctor advises an eye removal the patients always get shocked
and worries about what the operation involves and their appearance
after the eye removal. These are normal reactions and I hope that the
information below will help to answer some of these anxieties.
Reasons for Removal of an Eye
The eye needs removal because
 It is blind and painful.
 It has developed some Tumours (malignant).
 After a severe injury.
The answer is that an eye removing operation is not recommended
lightly and undertaken only when all other treatments are ineffective,
inappropriate or undesirable.
It is the final measure, taken in the best interest of the patient, by the
Ophthalmologist (an eye doctor) after a great deal of consideration and
consultation with patients, parents and if required with other
Ophthalmologists.
Removal of an Eye
Patient is usually admitted to the hospital one day before the surgery for
tests to check their health because the operation involves having a
general anaesthetic. General anaesthetic is administered to the patient
for this operation so the patient will be asleep during the procedure that
takes about an hour.
Before the operation the patient will be asked to sign a consent form for
this surgery which is a necessary.
Enucleation is the surgical removal of the globe (eyeball) only. The
eyelids, brow and surrounding skin are all left intact.
The eyeball is removed by incising and preserving the conjunctiva and
detaching the muscles from the eyeball, the optic nerve is severed.
An implant such as a plastic ball, Hydroxyapatite ball or Medpore ball
may be sutured into the socket (space left by the eyeball), the muscles
are re-attached around this and then it is covered with conjunctiva (the
mucous membrane which lines the inner surface of the eyelids and
stretches over the white part of the eye and the cornea, the coloured
part of the eye), which is sutured together over the implant to give the
socket a moist and pink look. A conformer (a clear plastic shell) is put in
place behind the lids. This gives some shape while the socket heals.
The operated eye will be covered with a pressure pad and dressing for
12 to 48 hours. During this time the patient may experience difficulty in
opening the lids of the un-operated eye. This can be frightening because
it means that the patient may not be able to see at all, but it only lasts
while the pad is in its place. The pad is intended to reduce swelling of
the tissue in the socket. As the anaesthetic wears off the patient may
feel some pain in the socket or have some sickness that can be relieved
with medicine. Normal activities can be resumed as soon as the patient
feels fit for it.
When the eye pad is removed, the nurse caring for you will clean your
lids and the Ophthalmologist will examine the patient’s eye socket with a
torch and prescribe eye drops or ointment.
The eyelids may be swollen and bruised for a few days. The patient may
be asked to use dark glasses till the swelling subsides. The socket is left
unpadded to promote healing.
Initially when the patient opens eyelids the patient may see the moist,
pink socket lined with conjunctiva. If there is a conformer (shell) in place
the patient will see the clear plastic with a hole in the centre. The shell is
only there temporarily until the socket heals and stock artificial eye or a
custom-made artificial eye can be fitted. Usually it takes six weeks
before the custom-made artificial eye can be fitted.
Medication
In case of the patient being a child of less than two years age. Only
enucleation is performed and non absorbable sutures are placed on the
four rectus muscles so that they can be identified afterwards for putting
the motility implant when the child is a little older.
Aftercare
Patients are taught, by the nursing staff, to look after themselves and the
eye as soon as possible. Patients are advised to stay in the hospital till
they are confident that they can take care of themselves, usually a few
days. In some circumstances, family and friends are taught, so that they
can help the patient.
Initially the patient may need to clean the lids with cool, boiled water to
remove any mucous. If this mucous becomes excessive or discoloured
the patient should see the Ophthalmologist.
Hands should always be washed thoroughly before touching the
operated area and it is advisable not to touch the socket. The patient
may need to wash the shell, initially twice a day with soap and water.
Rinsing thoroughly to ensure that no soap remains on the shell and
replace it. Patient can wash the face normally.
If the shell falls out on its own, which is rare, clean it thoroughly with
soap and water and rinse it thoroughly before replacing it.
For the first few weeks the patient has to put eye drops to prevent
infection. The patient need not remove the shell or artificial eye to instil
eye drops or ointment.
Ophthalmologist refers the patient to an Ocularist for fitting of artificial
eye.
The Ocularist will decide when to give a custom-made prosthesis. This
involves the moulding of patients eye socket using impression material
(a painless procedure) and hand painting of the eye colour. The eye
shape, size and colour are made to match the good eye so that it is
difficult to tell them apart.
There should be an adequate range of eye movements of the artificial
eye if it is custom made. The prosthesis can be worn without removing
for days together. It can be worn during sleeping hours as well. The
discharge is reduced if it is custom-made artificial eye (prosthesis).
The patient can wear eye make-up once the socket is healed
completely.
Patient is advised to wear goggles when swimming and remove the
artificial eye if diving or water skiing to prevent loss.
It is necessary to wear protective goggles when doing anything that may
cause injury to the remaining good eye.
5 TYPES OF PROSTHESIS
Different types of Ocular Prosthesis are used to treat different problems.
For simple corneal opacities instead of doing tattooing one can use
cosmetic contact lens. Opacity away from the visual axis of the cornea
can be hidden behind the prosthetic lens with a clear pupil. This lens can
be powered for any refractive correction for the seeing-eye.
If the corneal opacity is big or on the central cornea (pupil) then iris
painted with a black pupil prosthetic is used.
On occasions the non-seeing eye, over a period of time, becomes
divergent. In such cases off-centred prosthetic lens can be used.
Where the cornea is irregular a soft or hard lens cannot be fitted then a
Sclera lens or a Cosmetic shell has to be considered.
In a situation where the size of the eyeball has shrunk (phthisical
eyeball) one has to use a Cosmetic shell.
If the eye is eviscerated or enucleated one has to use an Artificial Eye.
Difference between an Artificial Eye and a Cosmetic Shell is that the
former is thicker than 2.5 mm.
Many countries do not have a trained Ocularist so they are forced to
depend on stock eyes which are prefabricated. Though they are cheap
and readily available, they often do not match the natural eye and tend
to cause discharge and discomfort. In the long run they cause lower lid
sagging. They also restrict movement and wearing period.
In some cases, a stage is arrived at, where no artificial eye can fit the
socket, it just pops out as the lower fornics get inverted or a mass of
tissue grows in the hollow cavity of the stock eye, which push out the
prosthesis on upward guise. The socket can get contracted as well.
To solve these entire problems one should always use custom-made
Artificial Eyes or Shells as the look more natural and greater movement
with comfort and prolonged wearing periods.
A significant advantage is that custom eyes and shells give much less
secretion the patient feels more comfortable and forgets the problems
created by an uncomfortable eye or shell. As a result the patients
become more confident interacting with other people in the society.
An additional advantage of custom-made Eyes and Shells is that
modifications can be made to the prosthesis in order to develop or
expand the contracted socket; depth of the cul-de-sac can be expanded
with special edge design.
Some special design can reduce the effect of ptosis. A notch can be
developed on the Artificial Eye surface for correcting a severe ptosis.
For the divergent non seeing-eye correctly painted iris avoids surgery
and gives a normal look. It places less or no weight on the delicate lower
lid.
Patients can wear the custom-made prosthesis even during sleeping
hours without having to remove it for many days.
For a totally exenterated eye one has to give a facial prosthesis to be
mounted on spectacles. Magnetic implant can hold the prosthesis in
place if an iron sheet is placed inside the prosthesis.
For natural eye movements intra orbital implant of Hydroxyapatite or
Medopore can be drilled in the ball and socket type or direct attachment
can be made to the Artificial Eye to achieve more natural eye
movements.
6 FACIAL PROSTHESIS
Facial Prosthesis (fig. 6.1) or external prosthesis is used for the patients
with exenterated eye. It can be made of silicone rubber or hard acrylic.
The life of silicone prosthesis is about 2 years, whereas acrylic
prosthesis can last for about 10 to 15 years.
The external prosthesis needs to be attached to spectacles or a
magnetic implant can hold the external prosthesis at the given position.
The patient needs to get his spectacles, with the prescription, if any, for
the seeing- eye. The same prescription has to be incorporated, in the
frame, on the non-seeing side. The cylindrical power in the seeing-eye,
should also be kept on the non-seeing side. If the axis are 90 or 180
then there is no problem keeping the same power on the non-seeing
eye. But if it is not 90 or 180 then the axis needs to be transposed i.e.
add or subtract 90 degrees from the axis that will give you the correct
magnification on the non-seeing eye.
Impression of the patients face is taken with alginate, while alginate is
setting; fast setting plaster gauze is placed on the alginate which will
give required stiffness to the impression.
Using this impression a cast is made out of this and using base plate
dental wax is sculpted the eye and other portions surrounding the eye.
The eye has to be custom-made beforehand to match the iris and the
sclera etc.
Using this eye the facial prosthesis is sculpted. The eye plane position
and protrusion are considered while sculpting the prosthesis.
Once satisfied with the wax sculpting a plaster mould is made and pink
acrylic is cast out this the position of the eye is cut off from the back side
and the custom-made eye is put in its place and sealed with self curing
acrylic.
Artificial eyelashes are used and painting of the prosthesis is done with
oil colours using chloroform to match the patient’s skin shade.
This prosthesis is attached to the spectacle permanently or using a wire
attachment.
7 VISION WITH ONE EYE
Vision is the most important sense out of the five senses that we
possess.
Light coming from the surrounding objects is perceived through the eye
and is converged on to the retina after travelling through the cornea, the
aqueous humour, the crystalline lens and the vitreous humour.
Millions of retinal cells of rods and cones convert these photons of light
into signals through the nerves by reversible chemical reactions and the
signals are carried to the brain’s occipital cortex and are analysed,
stored, evaluated and based on previous experiences necessary action
is taken by the brain.
Seeing
Seeing is a learning skill, our vision develops as we grow. Since birth till
the age of 4 to 5 years growth is faster and during this period one learns
to see. It takes an educated brain to understand and evaluate the given
images.
Every individual is right-eyed or left-eyed. Depending on which side of
the brain is dominant, the individual becomes a righty or lefty.
In general right side of the body is controlled by the left hemisphere of
the brain, and vice versa. Therefore in the case of the eye it is the image
falling on the right side of the retina of both eyes are sensed at left
occipital cortex and vice versa. Hence loss of right eye in a righty
individual makes the situation more difficult than in a lefty individual.
There are other factors that affect the readjustment after the loss of an
eye, visual acuity of the surviving eye and the structure of the society
and surrounding.
Age is also an important factor in getting used to the new one eye
situation.
If the patient is one eyed since birth the patient will have less difficulty in
moving around as the patient’s brain has learnt by taking information
from one eye only. However, if the patient has lost an eye afterwards it
takes a long time to learn the new situation. The loss of vision may be
gradual or sudden also makes a difference. In case it is gradual, patients
also learn gradually to adapt but if it is a sudden loss of vision it more
difficult to adapt with one-eyed vision. It may take as long as a year to
re-educate the brain. If, on the other hand, the patient understands the
mechanism of seeing and learns how to readjust the patient can get
back their confidence very quickly. The patient’s psychological state of
mind also has bearing on adaptation period.
When one eye is lost the person’s horizontal field of vision becomes
narrow. The depth of perception is impaired and the whole visual system
including the brain is in disarray and in need of many adjustments and
re-education.
Mechanism of seeing (fig. 7.1)
We live in a three dimensional world hence our seeing has a lot of
information coming from all the dimensions.
Our brain understands objects by their size, shape, colour, shadow and
its relativity to other objects and previous experiences.
When a distant object is seen the visual axis are practically parallel, the
object forms an image upon each fovea (retina). Other objects to one
side, i.e. either on the left or right will form their images on the opposite
side. An object on the right will form its retinal image on the temporal
side of one retina and an object on the left will form its image upon the
nasal side. These retinal areas are coordinated visually in the occipital
cortex so that an object seen with both eyes is seen as a single object.
The image of the right side falls on the lateral side of the left eye and
nasal side of the right eye. In the same way the image of the left side
falls on the nasal side of the right eye. Optic nerves cross at the optic
chiasma and image on the right is sensed at the left occipital cortex and
left side image is sensed at right occipital cortex.
In case of eyes the information is received by two different angles and
these two images are superimposed on each other in the brain.
When Sachin Tendulkar swings at a pitched ball, his body moves in
intricate balance, responding to a complex set of orders initiated by the
eye. Visual messages trigger a chain reaction that coordinates muscles
and brain. Signals from the eye speed along the optic nerves to the
visual cortex. Some of these impulses reach the motor cortex and frontal
association cortex and are swiftly relayed to the spinal cord. The spinal
cord in turn sends messages to the muscles, setting the body in
practices, well coordinated motion.
Field of Vision (figs. 7.2 & 7.3)
The normal field of vision is 180 degrees, with one eye it is about 140 to
160 degrees and one eye’s field of vision superimposes the blind spot of
the other eye thus achieving 180 degrees field of vision. With the loss of
one eye one has only 140 to 160 degrees of field available and hence
one has to use one’s head movements to compensate the field loss.
Depth Perception (fig. 7.4)
Depth perception requires understanding the size and distance of an
object. It is a complex procedure that involves psychological factors and
accommodation-convergence ratio.
Each eye sees an object with a slightly different angle and the brain
makes use of this information to understand its size and the angle of
convergence and the amount of accommodation provides the distance
sense. Since the two eyes have to converge on the same object to view
it, the closer the object greater the angle of convergence, this
information is used for computing the distance. When the object is more
than 6 meters away the eyes do not converge so this information is not
of much value. At the same time, at this distance, the details of the
object are less obvious.
Eye is at rest when focussing at a distance of more than 6 meters, when
one has to view closer objects, the crystalline lens of the eye changes its
dimensions to increase its focal length to bring the object into sharp
focus on the retina; this phenomenon is known as “Accommodation”.
Now the amount of accommodation is greater when viewing closer
objects. To focus an object at 1 meter distance the eye has to increase
the dioptric power to increase to 2 Diopters and so on. This information
is used by the brain to compute the distance of an object.
For the one eyed convergence is of no value but accommodation
information is used for depth perception along with the size, shape,
colour, shadow and brightness of the object as well as previous
experiences.
Action after seeing
The relationship between eyes, brain and body has developed since
birth. Seeing is only part of visual process that involves all other
elements of the system to respond to reactions between all these
elements with amazing swiftness and sensitivity.
When you read, your brain consults its vast memory bank in order to
make a judgement about it. It tries to analyse the information received
and it is stored for further use or reference, in respective areas of the
brain. If required action is taken depending on the situation, e.g. you turn
the page, as your brain sends the commands via the nervous system to
activate the body’s motor system, and your fingers obey the order to turn
the page.
When the brain receives an impaired or different visual message you
see illusions. When you have no past experience about the subject of
the message, say due to loss of one eye, the message received by the
brain is not fully analysed and you make mistakes. Hence, one has to reeducate the brain for one eyed-vision.
Re-Educating the Brain
A photograph is a two-dimensional picture, somewhat similar image is
perceived with one eye. When one eye is lost you do not see a little to
the right and left due to reduced field of vision. So far, the other, the lost
eye, was compensating for that, and providing 180 degrees of the field
of vision. Secondly, with one eye lost, one does not have two slightly
different images, with different angles, and there is no convergence of
the eye, to see the image. Hence what one sees is flattened-out scene
like a photograph.
If you move your head a little, all the surrounding objects will be seen
with a different angle, and suddenly they will come to life with three
dimensions again. One’s brain gets the information of relativity that gives
the objects their accurate positions and sense of distance from each
other.
Relative motion
When one moves one’s head and try to see the same object, what one
does is one gets more information about the object due to relative
motion of the object against the surrounding.
The relative motion will compensate for binocular vision and help a
one-eyed person to come back to normal life.
Knowing this one can readjust to the situation very fast. One can make
use of this relative motion in all one’s activities like driving, boating,
skiing, skating etc.
Understanding the perspective of the object also help to judge its
distance and size-shape i.e. three dimensional image.
If you see a photograph, you can understand that the objects which are
closer take up greater area, of the photograph, than the objects, of the
same size, at a distance.
Colours also look more bold and bright in the foreground, whereas in the
distance they appear softer and muted. Shadows of the near objects
appear sharp and dark and distant objects look blurry while a closer
object looks sharp.
These observations are important for a one-eyed person. If you know
the real size of the objects you can estimate its distance from you.
Tips and suggestions for one-eyed patients
In an everyday life of a one-eyed person many challenges are faced like
a hand shake, cooking, dining, travelling by train or bus, driving etc.
Here are some tips to make life easier
For shaking hands bring your hand in line with the other person and then
slowly move forward till the hands meet – this is the best way to ensure
that the hands do not miss each other.
Whilst cooking, one needs to pour or transfer things to a bowl or utensil.
The best way to do this is to touch the bowl or utensil with a spoon or jar
to transfer the contents in order to ensure that contents do not spill on
the floor.
Moving your hand horizontally will give you understanding of the
surrounding field.
Moving your head, horizontally from side to side, will ensure that you do
not collide with people or objects and will make it easy to move around.
While dining one should move one’s head towards the lost eye side
before making any gestures on that side.
While climbing or descending, steps or stairs, ensure that you know
where the first and the step is. Making sure by using your toe or keeping
a hand on the railing will avoid undue accidents.
While crossing the road one should concentrate on the edge of the
footpath while moving ahead, this will show the road ahead and allow
one to gage the height of the footpath from the road. While crossing the
roads one should see both the sides by moving the head in both
directions, particularly on the limited peripheral vision side whilst making
a move.
Driving a car with one eye is a difficult task. While driving if the car in
front of you moves at the same speed as yours it is difficult to judge its
distance from you what you should do is to either slightly increase or
decrease the speed of your car which will give you the relative motion
and you will be able to judge the distance. While coming out from a
parking lot you can follow the car in front of you or you can take your
passengers help to drive or you can drive close to the line of cars on
your right with your head out of the window if found necessary. While
parking again you can take your passengers help, or come out of the car
and judge the distance between the cars and the situation or select a
parking slot where there is plenty of room for parking. Make use of your
headlights, even during daytime, to help you judge the distance from
other cars while parking. The pattern of the beams will help judge the
distance. Selecting a car can also make your life easier. The car that
gives you the greater clearer front view, headlamps and reversing lights
will of helpful and the smaller the car better the control and easier
manoeuvring.
Loss of an eye need not mean an end of all activities in fact one can get
back to normal or even better performance in life, in all fields by
determination and re-education.
Precautions
With a loss of one eye it becomes of paramount importance to safeguard
and protect the surviving eye. Eye specialist or an Optometrist can tell
you whether you need prescription glass for the surviving eye. It would
be wise to wear eyeglasses that are toughened and are impact resistant.
Rimless are to be preferred. Antireflection coating on the glass will be
advantageous as it will increase visibility and reduce reflection and ghost
images. They are also useful for driving. Having the same prescription
for the non-seeing eye will increase the cost but will give a better
cosmetic appearance, which is explained in detail the “Cosmetic Optics”
chapter. Good lights and lighting and contrast will compensate for
impairment in vision.
Taking care of the Good Eye
It is important to give special consideration to safeguard and care for
eyesight of the one remaining eye. As the persons future depends on
that seeing-eye as, if something should go wrong with the good eye,
total blindness will be experienced which, naturally, is unwelcome.
Therefore the surviving eye should be well protected. It is a myth that
one cannot lead an active life with one seeing-eye; it is a false belief that
one should not use one’s good eye too much.
Regular, annual, eye examinations by an Ophthalmologist are advisable.
Any new sign, symptoms such as redness, blurred vision, pain, heavy
discharge or headache should be immediately reported to your eye
doctor.
Even a small change in vision can be disturbing for a one-eyed person.
It is necessary to test your eyesight more often and change the glasses
with corrected prescription if and when necessary.
Special attention should be paid to situation like injuries, infections,
Glaucoma, Cataract, Retinal Detachment, Diabetes, High myopia
(explained in detail in other chapters) for which proper medical advice
and prompt treatment should be taken to preserve the good eye.
Non-Seeing Eye
If, your eye is enucleated or eviscerated an artificial eye or a cosmetic
shell can rehabilitate you cosmetically. If you use a ready-made artificial
eye, it will give you a discharge, discomfort, watering and restricted
wearing period, artificial look rather than natural, and restricted or no
movement. In the long run your lower eyelid will sag due to the weight of
the stock eye and you will need surgical correction. To overcome these
problems one should use a custom-made artificial eye and if possible a
peggable integrated orbital implant, that will give no weight on the lower
lid. This is discussed in the chapter “Ocular Prosthesis” in detail.
Contact Lens
A one-eyed person who needs corrective lenses for the seeing-eye can
benefit with the use of contact lens as it gives best corrected visual
acuity and widest field of vision.
Good care of the lens under medical supervision is essential. Your eye
doctor or an Optometrist can help you understand and advise you of the
best contact lens for you.
Cosmesis
Even if you have lost an eye, by cosmetic surgery and using a custommade eye prosthesis you can look normal, but some defects do remain,
like restricted movement at extreme ends or a difference in the two eyes,
after all it is artificial. Both eyes may not move in unison, while looking
side-ways the artificial eye may lag behind, the best thing to do, to avoid
this, is to move your head, rather than just your eyes, while seeing
side-ways. When talking to someone face the person and look straight in
the eye. This will avoid the other person from knowing that your one eye
is not real.
Parenting
Parents of a one-eyed child have to be careful and understand the
sensitivity of the subject while talking to the child. If one is not careful
and undiplomatic, one can damage the child’s emotional outlook which
is more important to the child than the physical loss of an eye.
Any discussion of the loss must be adjusted taking into account the
child’s age, sex, emotional stability, maturity, natural coordination and
their relationship. Parents should understand the impact of an eye loss
and should not exaggerate fears of the loss. Children usually adapt
themselves faster to the new circumstances than adults.
You can be reassured and make the child understand that monocularity
can set very few limitations and he/she is not the only one in the world
with one eye, there are many great people and personalities in the world
with one eye.
8 OCULARIST
An Ocularist is a carefully trained technician skilled in the arts of fitting,
shaping and painting Ocular Prosthesis. In addition to creating it, the
Ocularist shows the patient how to handle and care for the prosthesis
and provides long term care through periodic examinations.
There is no school or institute around the world to produce Ocularists.
But the art and science of making artificial eye is learnt by observation
and supervision of a practicing Ocularist like an apprentice-ship.
To become an Ocularist one should have a good artistic hand and
understanding of primary medical and chemical knowledge and a lot of
practice.
Every case is different and needs careful consideration and needs to be
dealt with separately.
An Ocularist has to deal with a patient who has lost a vital organ of the
body are often under psychological trauma. The y needs to be handled
gently. One must have a caring attitude towards the patient and should
try to put the patient at ease and deal with their tension.
Patients often come with great expectations, one should explain the
limitations of the art and science of the Ocular Prosthesis or making of
an Artificial Eye, after all it is an artificial item and has to compete with
nature. Only God or Nature can make a new live eye. Humans have
their limitations in competing with nature. One should try to give their
best in making an artificial eye look natural. An Ocularist should explain
to patients with singular vision to re-educate themselves, making their
rehabilitation faster in society.
All over the world there are around 500 to 600 Ocularists at present.
There is a vast need of trained Ocularists to help disfigured eye patients
to rehabilitate them cosmetically and socially.
One can get more information on Ocularistry on the internet by visiting
the following web site:
www.ccularist.org and www.oculaplastic.com
www.ocularist.co.in
9 A DAY WITH AN OCULARIST
When a patient with one eye visits an Ocularist to get his/her eye custom
made, the Ocularist will examine the eye socket and carefully note your
history and will explain what he can do and how he proposes to go about
it. He will also give you an estimate of cost. The fees cover cost of the
prosthesis and your subsequent visits.
He will then give you an appointment. On the day of the appointment, he
will take an impression of your socket with alginate which is a painless
procedure. He will then make a mould of wax out of the impression
taken and will attach an aluminium button to the wax model and this wax
mould is tried in the eye socket. He will then position the aluminium
button for exact location of the pupil and at the same time he will sculpt
the wax model to an exact size, shape and lid closure.
Once the Ocularist is satisfied with the wax model, he will paint a PMMA
(poly methyl methacrylate) corneal button by reverse painting technique
or he will reproduce the iris colours on iris disc, which then glued to the
corneal button.
Iris painting and wax model sculpting may take an hour or so, and then
the patient is free for two hours. During this time the Ocularist makes a
mould of wax model in stone plaster. Using the plaster mould he will cast
a white scleral shade plastic along with iris cornea unit.
The Ocularist will smooth and polish the complete unit and will try it in
the eye socket. Once satisfied with the size, shape, location of iris and
the lid closure he will cut some portion white plastic and will do some
fine painting on iris and will imitate the blood vessels and paint the
scleral shade to match the other eye. This may take another hour or so
and again the patient free for two hours.
The Ocularist will then process the eye with clear plastic and will smooth
and polish it with high precession for the final fit and delivery.
The Ocularist will then teach you how to insert and remove your artificial
eye and how to take care of it.
He will clean the prosthesis and fit it in your eye socket and show you in
a mirror to see the effect for yourself. If he is satisfied with the work he
will give the prosthesis to you if however he feels that he can do some
more work on it to make it more natural he will not give you the eye and
will give you another appointment for the same.
Many times patients cannot make out the results as they are not used to
seeing themselves with a natural looking eye in place of the missing eye.
It may take some time for the patient to get used to the new look.
It is advisable to bring along a friend or a relative for the day long ordeal.
When patients come for refitting after using some prosthesis, many
times he feels that his old prosthesis looks good, as he/she is used to
seeing themselves with it for a long time and it takes a day or so for
him/her to appreciate the new artificial eye and the way it looks.
Many Ocularists do the prosthesis in two sittings. In the first visit
impression, wax model and iris painting id done and on the second visit
sclera painting and delivery is carried out.
10 CARING FOR YOUR OCULAR PROSTHESIS
Whenever a prosthesis is removed from the eye socket it should cleaned
using soap and water (liquid soap would be a good idea) and rinsing it
thoroughly with water to remove all traces of soap from the prosthesis, if
this is not done thoroughly it may cause more discharge. This can turn
into a vicious circle.
The more times the patient removes the prosthesis, even just to rinse it,
the more secretion there will be. It can take 2 to 3 days to get used to a
new prosthesis, before the stability is reached, with little secretion.
Frequent removal to rinse the prosthesis increases the production of
secretions, which in turn gives one the feeling of having to remove the
prosthesis more often
Daily Care
A blinking action, with upper lid moving over the front surface of the
prosthesis, will cause it to be cleaned without having to remove it. To
keep these areas clean, moisten a clean tissue paper or a clean
handkerchief, with warm water and rub lightly, as and when needed.
For a thorough cleaning place the prosthesis in a small bowl filled with
very hot water (never use boiling water). Leave the prosthesis soaking in
the hot water until the sediment (deposits on the prosthesis) has
softened, that can take about 15 seconds. With clean soft cotton or
clean tissue paper rub the prosthesis vigorously for 30 seconds, then
replace the prosthesis in the water and rub again vigorously. If the
prosthesis remains dull and rough, repeat the procedure changing hot
water 2 or 3 times. A bright light reflecting off the surface of the
prosthesis will permit you to identify any remaining deposits.
If your eyelids do not close completely or if you work in an environment
with air conditioning, smoke, dust, cold air or excessive ventilation, very
hot air, driving or commuting by train, bus with excessive air blasting on
the face (like standing in the door on a train or sitting next to a window
on a bus) you might find that you need to remove your prosthesis more
often to clean it.
Attention
If you have had your prosthesis polished annually by your Occularist and
suspect the presence of an infection, it is advisable to consult your
Ophthalmologist.
During medication, if eye drops or an ointment has been prescribed,
apply with the prosthesis in the cavity, it is not recommended to let the
cavity heal or recover from an infection, without the presence of a well
cleaned prosthesis. If you are wearing an old prosthesis, which can
damage the tissues, your Ophthalmologist or Occularist should place a
temporary prosthesis called a “conformer”. This will facilitate the healing
process or recovery from an infection with less risk of the socket
contraction. Afterwards the Ocularist will proceed with the fabrication of
a new custom-made ocular prosthesis. For hygienic reasons many
people admit to having boiled their prosthesis or having disinfected it in
or with alcohol, both practices should be absolutely abolished as they
can cause irreversible damage to the prosthesis.
Visit your Ophthalmologist and your Ocularist annually for an
examination, verification and, if required, polishing. If you have problems
or questions, during the year do not hesitate to contact your Ocularist or
Ophthalmologist.
For further details you can write to:
Chandrashekhar Chawan
Director - Shekhar Eye Research Pvt Ltd
108 Falcon Court, Hari Om Nagar, Mulund (E), Mumbai 400081 India
T +91 22 25327459 / 56 Fax: +91 22 25327410 Cell +919892416978
Email: shekhar@shekhareye.com
Website: www.shekhareye.com
11 NATURAL EYE MOVEMENTS (figs. 11.1 & 11.2)
Even with custom made artificial eye patients cannot get totally natural
movements of prosthesis as it is not attached or sutured to the tissue
behind, in the socket. It is just sitting right in the socket, so that there is
less friction while moving the eye. But when looking at the extreme right,
left and upwards the prosthesis do not move to such extent, due to
tissue restriction and weight. Due to this restricted movement, patient
has to move his/her head in the direction of gaze rather than moving
his/her eyes.
Other people can make out the artificialness in the prosthetic eye, as
artificial eye does not move in conjunction with the natural eye.
In order to overcome this shortfall “Intra Orbital Implants” made of
Hydroxyapatite is used.
Dr. Arthur Perry of USA had first implanted the intra orbital implant of
Hydroxyapatite in May 1985. Now it is famous in the world under the
name “Bio Eye hydroxyapatite Implant”, which is supplied by “Intra
Orbital Implants, Inc. USA.
In India Dr. Quresh Maskati first implanted this, hydroxyapatite intra
orbital implant, in 1992.
The hydroxyapatite implant is surgically placed within the orbit and the
tissue is closed over the implant. A temporary conformer is placed over
the implant and under the eyelids to maintain the space for the artificial
eye.
After 6 to 8 weeks an Ocularist can make a custom made artificial eye to
match the patient’s good eye. This eye is fitted over the implant and will
move in conjunction with the natural eye.
If extreme movement is desired, the Ophthalmologist will drill a hole in
the implant after 4 to 6 month as this much time is required for the blood
vessels to grow in the implant, thus it becomes a part of your body. A
peg is inserted into the hole and a month later, an Ocularist can modify
the back of the artificial eye to accept the head of the peg. This forms a
ball and socket attachment. If there is no room for the ball and
socket, an attachment peg can be directly glued to the back of
the artificial eye. After this attachment the artificial eye will move
to the extreme ends with the good eye and the patient gets full benefit of
the implanting procedure.
The final result in each case is different depending upon the condition of
the orbit, muscles and surrounding tissues.
Even with a pegged artificial eye one cannot get 100% eye movement. It
is advisable to put some kind of intra orbital implant after an eye removal
in order to fill up the lost volume of the socket and for better fitting of an
artificial eye.
12 READY MADE Vs CUSTOM MADE EYE
“Custom Made Artificial Eye” is made by using “impression technique”
by, taking an impression of the patient’s eye socket i.e. tailor made
specifically for a given patient to his/her measurements , it is not simply
just a question of matching the iris and scleral shades and a fixed back
curvature as a stock eye.
Many ready-made eye manufacturers give iris and scleral shade
matching prosthesis and call it custom-made; it is not a custom-made
artificial eye in any sense.
The only advantage offered by a ready-made artificial eye is that it is
cheap and readily available.
In the long run the disadvantages become obvious:
 Poor matching with the good eye as it is not painted to match
the good eye.
 Little or no movement as the back surface of a ready-made
artificial eye is hollow and not made to match the tissue behind
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the eye. Hence the artificial eye only looks straight ahead and
cannot follow the other eye movements.
Whole weight of the ready-made artificial eye is on the lower lid
therefore in a few years the lower lid starts sagging down
requiring further reconstructive surgery of the lower lid.
Tissue in the lower fornix grows in an upward direction due to
loss of facial attachment of lower fornix to periosteum, trying to
fill up the hollow back of the ready-made artificial eye over a
period of time, leading to falling off of the prosthesis, on looking
up, requiring the patient to undergo reconstruction of the fornix
surgically to correct the position.
Discharge and watering becomes a problem with ready-made
artificial eye. Due to constant rubbing of the tissue behind
patient starts to get heavy discharge frequently that tends to
accumulate in the hollow back of the prosthesis. Due to
accumulation of the discharge tissue secrets more discharge,
requiring frequent cleaning which restricts wearing period, this
creates awareness of the deformity creating an inferiority
complex for the patient.
Often ready-made artificial eye can give proptosis effect i.e.
one eye looking bigger than the other.
If the ready-made artificial eye is used during sleeping hours,
both the eyelids stick together due to heavy discharge in the
morning.
To overcome all these problems and complications a custom
made artificial eye is the solution.
The advantages of a custom-made artificial eye:
 Close matching with the natural eye, as it is hand painted to
match the other eye.
 Greater movement due to exact matching of the back of the
prosthesis with the tissue structure in the socket.
 Virtually no discharge or watering as there is no or very little
friction with the socket tissue and custom-made artificial eye;
tears also get properly drained in to the punctum in most of the
cases.
 Patient can wear the custom-made artificial eye days custommade artificial eye together continuously including sleeping
hours, as there is very little discharge in the morning similar to
the normal eye.
 Most of the weight of the custom-made artificial eye is
distributed over the tissue inside and not on the lower lid. Peg
attachment to the artificial eye can take all the weight of the
prosthesis on it placing no pressure on the delicate lower lid.
 There are no complications like lower lid sagging or inverted
lower fornix or contracted socket with the custom-made
artificial eye made by using impression technique.
 Modifications are possible with the custom-made artificial eye
to solve many problems like mild to severe ptosis, proptosis or
need for socket expansion with surgery etc.
Custom-made ocular prosthesis play a very important role in the
development of orbits of anophthalmic / microophthalmic children i.e.
children born without an eye or if an eye has had to be removed
surgically at an early age.
If the advantages of newer developments in the field of ocular prosthesis
and cosmetic surgery (Oculoplastic surgery) are used totally, patients
with disfigured eye can be rehabilitated socially and psychologically.
13 ANOPHTHALMIA AND MICROPHTHALMIA (fig.13.1)
This chapter is contributed by researcher at Albert Einstein Medical
Centre (AEMC) in Philadelphia
Anomalies of the eye and central nervous system are among the most
common encountered in paediatrics. In the case of Anophthalmia and
Microphthalmia, it is thought it is thought to be on a continuuam ranging
from mild coloboma (a keyhole or a notch like defect in the retina, iris or
optic nerve) to severe anophthalmia. Anophthalmia is a medical term
used to describe the complete absence of the globe and eye tissue from
the orbit. Microphthalmia is defined as small eyes and can range from
mild to severe. The terms Anophthalmia and Microphthalmia are often
used interchangeably, since CT scan and MRI may show some
remnants of either the globe or surrounding tissue. Anophthalmia /
Microphthalmia (A/M) may affect only one eye with the other being
normal or both eyes, resulting in blindness.
After congenital cataract, Anophthalmia and Microphthalmia are among
the most frequent eye malformations in humans.
(1) The exact incidence of A/M is unknown. In a recent study in
England, the overall prevalence of A/M was 1.0 per 10,000 births.
(2) Anophthalmia can be congenital (at birth) or acquired later in life
(after an injury). Congenital anophthalmia and microphthalmia can
occur alone or along with other eye problems (e.g. cataract or
coloboma) or birth defects (e.g. heart or brain defects).
Anophthalmia and Microphthalmia may result from inherited
genetic mutations, sporadic (by chance) genetic mutations,
chromosome abnormalities, parental environmental insult
(maternal diabetes, infection or alcohol) or other, as yet unknown,
factors.
Comprehensive Health Care Team
When a child is born with Anophthalmia/Microphthalmia, a
comprehensive health care approach is essential to help the baby and
the family to meet the challenges related to A/M and to live as healthy a
life as possible. The health care team should include evaluations by the
following professionals, either immediately or shortly after birth.
1. Paediatrician – A physician specialising in caring for children.
2. An Ophthalmologist – A physician specialising physician
specialising in problems related to the eye. An Ophthalmologist
often will make the diagnosis of A/M.
3. Ocularist – A health care professional specialising in prosthetic
(artificial) devices for the eye.
4. Oculoplastic surgeon – A physician who specialises in surgery of
the eye. Not all people with A/M will require surgery.
5. Geneticist – A physician who is an expert in genetic conditions.
6. Genetic counsellor – A medical professional specialising in support
and information.
The genetic team can help the family to co-ordinate special care and
early intervention for the child. If a specific diagnosis is made to explain
the etiology of A/M, the genetics team can educate the family and
health care team and provide anticipatory guidance and prognosis
based on the information available from all sources. In addition, the
genetics team can discuss the possibility of having another child with
A/M.
7. An early intervention specialist/teacher – A professional who works
with children who are visually impaired in one or both eyes to learn
and develop in a sighted world. An example of an early
intervention service is Orientation and Mobility training. Early
intervention specialists will determine what services your child may
need. Early intervention helps the child to maximise their
development and reach their full potential.
Genetics of A/M
In each cell of our body, are the chromosomes which are tiny structures
that carry our genetic information, which tells our bodies how to develop
and to function throughout our life. Our chromosomes arranged in 23
pairs (total of 46) with one chromosome of each pair, coming from the
mother (X chromosome) and the other from the father (Y chromosome).
Our chromosomes contain thousands of genes, which are made up of
DNA. Sometimes a change occurs in a gene which is called a mutation.
If a mutation develops in the gene concerned with eye development, it
could potentially affect how the eye develops during pregnancy. An eye
is affected in about one-quarter of all inherited diseases, thus possible
genetic defect causes eye malformation, must be considered as a
possibility. A/M has many different potential causes including genetic
conditions such as chromosomal disorders, single gene disorders and
multifactoral disorders.
A chromosomal disorder means there is an extra piece or missing or
rearranged piece of all or part of any chromosome. An example of a
chromosome disorder is Down syndrome. These individuals have three
copies of the chromosome number 21 instead of the usual 2. A
chromosome disorder can be determined when you child has their
chromosomes analysed with a simple blood test. However, if your child
has a normal chromosome analysis, it does not rule out a genetic cause
of A/M. A normal chromosome test only means that the cause is
unknown at that time.
A single disorder occurs as a result of a mutation in one gene or both
genes of a pair of chromosomes. Examples of a single gene disorders
are cystic fibrosis, sickle cell disease and Tay-Sachs disease.
Researchers are currently working on locating and analysing the gene(s)
involved in a normal eye development which may lead to answers about
A/M and enable geneticists to provide more accurate counselling and
recurrence risks.
Multifactoral disorders are the result of a genetic predisposition plus
environmental influence that leads to a disease. The exact genes and
environmental influences are usually not known. Examples of conditions
that are thought to be multifactoral are heart diseases and diabetes.
A comprehensive genetics evaluation may yield a diagnosis of a
syndrome or disorder with A/M as one of its findings. If a diagnosis is
made, the recurrence risk of that disorder can be explained.
Unfortunately, many times it is difficult to make a diagnosis. Without a
specific diagnosis, genetic counselling and determination of recurrence
risks are difficult. At this time, parental testing to look for normal eye and
lens development is available only in the form of high level ultrasound.
Genetic counselling is recommended prior to a future pregnancy.
Treatment of A/M
Facial development occurs very rapidly in an infant and young child. It is
believed that 90% of orbital growth is completed by the age of 5 years.
Growth and development of the face depends on the presence of an
average size eye in the orbital cavity. If an eye is very small or if it is
totally absent, the face cannot grow properly. Therefore, treatment for
A/M should begin as early as possible.
Treatment begins with an Ocularist. They may decide to use two basic
approaches. The first, most common approach to treatment is the
insertion of a conformer. A conformer is a tiny plastic device that looks
like a ball with a stem. The conformer helps to support the growth of the
eye socket and facial bones and to expand the eyelid opening.
The second approach is to make a custom-made conformer using the
impression technique. This approach allows the conformer to be shaped
exactly as per the child’s orbit cavity. One can also make an artificial eye
with the impression technique instead of a conformer, which will help
give an improved cosmetic appearance along with help expansion of the
socket and orbit. In some cases, the Ocularist will need to examine the
child under general anaesthesia in an operating room. At the same time
he will make an impression of the eye socket in order to make a custom
made prosthetic device.
The Ocularist will decide which treatment approach is best for the child,
depending on the individual needs of the child. In both approaches the
prosthetic device will need to be changed frequently as the child grows.
During the examination, the Ocularist will need to hold the baby still in
order to fit the conformer. The examination is not usually painful but may
be disturbing for the child who does not understand what is happening to
it. The Ocularist will separate the baby’s eyelids in order to examine the
socket. The baby may cry and resist examination (by a stranger), even
with the most gentle handling.
The prosthetic eye/conformer does not make a person with A/M see.
With our current knowledge and science, there is no device that will
allow a child with A/M to see. Anophthalmia is a condition that requires
visiting the Ocularist throughout life. During the child’s first year, many
ocular devices will be needed as the child grows and as the socket size
changes. The child may need weekly, bi-weekly or monthly visits to the
Ocularist. As the child grows older the frequency of visits will decrease.
The actual number of visits required differs from individual to individual.
It may take some time for the child to get used to wearing prosthesis. It
should not cause pain but if the child’s eye looks red or the child
indicates pain by frequent rubbing or pulling at the eye you should
contact your Ocularist immediately. Never remove the prosthesis
without the knowledge of your Doctor or Ocularist. Children may
remove and play with the prosthesis. You should replace it (in the
socket) following the procedure taught by your Ocularist. If you are not
able to replace it, contact your Ocularist without delay, as the socket
may begin to shrink if the prosthesis is not in place.
Over time and through necessity, everyone can learn to care for the
baby’s eye prosthesis and needs. Any concerns and feelings should be
discussed with your Ocularist, who is used to dealing with concerns
about these very important topics.
Recommendations for Individuals with A/M
Children may be born with A/M only, while others, may have
additional associated findings. It is suggested that any child born
with A/M have the following evaluations and studies carried out.
These evaluations and studies will monitor for potential problems
associated with A/M and help to ensure that children with A/M live
as healthy a life as possible. This may be a helpful list to give to
the Paediatrician.
1. Ophthalmologist / Oculoplastic surgeon.
2. Ocularist.
3. Clinical Geneticist.
4. Early intervention specialist and vision therapist (even for
children with only one eye affected).
5. Cardiology evaluation if a murmur is heard.
6. MRI or CT of brain and orbits.
7. Chromosome study.
8. Hearing evaluation.
9. Renal ultrasound.
10.TORCH titers (infection studies).
11. Dental examination when teeth erupt (especially for males).
12. Ophthalmology examination of BOTH parents (in order to rule
out eye problems that may not be affecting vision, such as
coloboma which can result in a more severe condition in a child).
Support Group information for A/M
The international children’s anophthalmia network (ican) is a
support group of healthcare professionals and family members of
persons with anophthalmia and microphthalmia. Ican offers
support to parents and family members, educational materials,
quarterly newsletters and bi-yearly family conferences. Ican can
be contacted through their hotline +1-800-580-ican (4226) or their
internet web page at www.ioi.com/ican
Research and A/M
Albert Einstein Medical Centre (AEMC) in Philadelphia works with
ican and has a Clinical Registry of individuals with anophthalmia
and microphthalmia from all over the world. The Clinical Registry is
compiling information on pregnancy histories, maternal medical
histories, family histories as well as environmental exposures. The
goal is to determine a more accurate incidence of anophthalmia
and to better identify all the syndromes that include anophthalmia
and to better identify all the syndromes that include anophthalmia.
The registry is a wealth of information for individuals with
anophthalmia, their families and healthcare providers.
Currently at AEMC, gene screening for eye development genes is
being undertaken in co-operation with several different laboratories
worldwide. All the laboratories are looking for changes in eye
development genes as a possible cause of A/M. Eye development
genes have the special function of being the blueprint for eye
development during pregnancy. Several genes are known to be
responsible for eye development in laboratory animals. Similarly
genes exist in humans. The DNA samples are analysed to
determine if a change exists, which alters the blueprint during
development and leads to A/M. To participate in gene screening
research, contact ican at 1-800-580-ican (4226) or AEMC at
215-456-8722.
References
1. Gotz W. Transgenic models for eye malformations.
Ophthalmic Genetics 1996; 16:85-104.
2. Dolk H., Busby A., Armstrong B., Walls PH. Geographical
variation in anophthalmia and microphthalmia in England,
1988-94.
British Medical Journal, 1998; 317:905-909.
14 AMERICAN SOCIETY OF OCULARISTS
The American Society of Ocularists is an International, non-profit,
professional and educational organisation founded in 1957 by
technicians specialising in the fabrication and fitting of custom artificial
eyes.
The organisation’s purpose is to improve and promote research in
development of ophthalmic prosthetics, to advance the methods,
techniques and skills of the Ocularist membership, and to provide the
public with continual improvement in all fields and activities in which
Ocularists engage. Our members adhere to the Society’s Standard
Operating Procedures for fitting and fabrication of custom made
ophthalmic prosthesis.
Research, education and standards form the benefits to our members.
Persons presently working in Ocularistry, or engaged in an ancillary
business or profession, may apply for membership.
A training curriculum, developed and administrated by the Education
Committee of the ASO, provides courses at semi-annual conferences to
prepare Ocularists certification and re-certification examinations of
National Examining Board of Ocularists.
http://www.generation.net/~oculoplast/nebo.htm
Research of new techniques stressing the benefits of custom-made
ocular prosthetics and product development, is published in the
Society’s Annual Journal of Ophthalmic Prosthetics.
15 FREQUENTLY ASKED QUESTIONS
What is an Ocularist?
An Ocularist is a carefully trained technician skilled in the arts of fitting,
shaping and painting ocular prosthesis. In addition to creating it, the
Ocularist trains the patients (or parents in case of a baby patient) how to
handle and care for the prosthesis and provides long term care through
periodic examinations.
How long have artificial eyes been around?
Artificial eye making has been practiced since ancient times. The first
ocular prosthesis, were made by Roman and Egyptian priests, as early
as the fifth century BC. In those days, artificial eyes were made of
painted clay, attached to cloth and worn outside the socket. It took many
centuries for the first in-socket artificial eye to be developed. At first,
these were made of gold with coloured enamel.
In the later part of the sixteenth century, the Venetians started making
artificial eyes of glass. These early glass eyes were crude,
uncomfortable to wear and fragile. Even so the Venetians continued
making them and kept their method secret until the end of eighteenth
century. After that, the centre for artificial eye-making shifted to Paris for
a time; but by mid-nineteenth century, German glass blowers had
developed superior techniques and the centre for glass eye making
moved to Germany. Shortly thereafter, glass eye making was introduced
in the United States. During World War II, the imported German glass
used for glass prosthesis became unavailable in the United States. As a
result of this shortage, the U.S. Government, in conjunction with a
number of American firms, popularised the techniques of making
artificial eyes out of acrylic plastic.
The popularity of this method has continued to increase over the years,
and today vast majority of patients wear ocular prosthesis made of
acrylic.
What is the difference between “Stock” and “custom” eyes?
“Stock” or “Ready-made” ocular prosthesis are mass-produced. Since a
“stock eye” is not made with any particular person in mind, it does not fit
any particular patient. A “custom” ocular prosthesis, on the other hand, is
made by your Ocularist to fit you and you alone.
How often do you have to see an Ocularist?
The ocular prosthesis, like hard contact lenses, needs to be polished
regularly in order to maintain the acrylic finish and ensure the health of
the surrounding tissues. It is generally recommended those infants
under 3 years of age, to be seen every 3 months; patients under 9 years
of age, twice yearly and all other patients, at least once a year.
How much does an artificial eye cost?
In the United States, the current cost for an artificial eye ranges from
US$ 3000 to US$ 4000. The cost of sclera shell prosthesis ranges from
Us$3500 to US$ 4500. The fee will largely depend on the amount of
work involved in order to achieve a satisfactory result. It should be
understood that it is very difficult for any Ocularist to quote a fee without
first examining the patient. The majority of Ocularists offer the initial
consultation visit without obligation and the charges are explained at the
time of the initial consultation visit.
Does Medical Insurance pay for an Artificial Eye?
If insurance coverage is available, most Ocularist practices will assist
you in every possible way to obtain full benefits of your policy in the
USA. However, it should be noted that the patient, (or in case of children
a parent or guardian) is always responsible for the payment, in case of
HMO’s it is always necessary to obtain a referral before work can begin.
What is the American Society of Ocularists?
The American Society of Ocularists (ASO) is a professional organisation,
which was established by a group of skilled American Ocularists in1957.
Their purpose was to promote high standards through research and
education in the field of Ophthalmic Prosthesis. Today the ASO
maintains quality Ocularistry through its formal education, training and
continuing education programmes.
How do I find a good Ocularist?
In most states, there are no laws governing Ocularists. When choosing
an artificial eye-maker, you should consult your state regulations and
look for the following credentials:
 Membership of the American Society of Ocularists.
 Certification by National Examining Board of Ocularists.
How does a person become an Ocularist?
There are no schools that teach Ocularisty. A person must learn how to
make artificial eyes through an apprenticeship with an approved
Ocularist (a Board Approved Diplomate Ocularist). The ASO apprentice
Program requires that the apprentice must study all aspects of ocular
prosthetics and spend five years (10,000 hours) in practical training. The
apprentice must also successfully complete 750 credits of related study
courses offered by the Education Program of the ASO. Upon successful
completion of all requirements, the title, Diplomate of American Society
of Ocularists, is awarded.
Does the Society arrange apprenticeships?
Apprenticeships are not arranged by the American Society of Ocularists.
A person seeking training must contact Ocularist in their area and locate
someone who is able to hire and train an apprentice. For people willing
and able to relocate, we suggest attending one of the biannual
conferences to meet Ocularists from different parts of the country.
Can I apprentice with any Ocularist?
To qualify for the Society’s apprenticeship program, you must train with
a Board Approved Diplomate Ocularist (BADO).
I already make artificial eyes. Do I have to become an apprentice?
Persons who are already working as Ocularists may apply to the
Society’s Associate program.
Aren’t there classes I can attend somewhere to learn to become an
Ocularist?
The American Society of Ocularists is the only organisation that offers
educational training in Ocularistry. Classes are offered at the Society’s
bi-annual meetings, and are designed to prepare Ocularists to take their
certification exams.
What courses should I take to increase my chances of becoming an
apprentice?
Although the science provides a good base, no special background is
required to enter an apprentice program.
Who certifies Ocularists?
The National Examining Board of Ocularists (NEBO) is an independent
entity whose directors come from the following participating
organisations:
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American Academy of Ophthalmology.
American Board for Certification of Orthoptics and Prosthetics.
American Society of Ocularists.
Public Member
NEBO awards the title, Board Certified Ocularist (BCO), to those
Ocularists who successfully complete a comprehensive four-part written
and practical examination. All BCOs must complete continuing education
requirements and be rectified by NEBO every six years.
For further details write to:
Cathi Guerrero
Executive Director
American Society of Ocularists,
1001 Mohawk Street, #16,
Bakersfield, CA 92209, USA
Phone: +1 661 633 1746
e-mail: cathi@ocularist.org
Web site: http://www.ccularist.org