Peripheral Retina Lecture
You must have a good understanding of the anatomical location of
the peripheral retina structures and their relationship to one
another. The peripheral retina is defined as the zone from the
equator to the ora serrata and is approximately three to four disc
diameters (3DD-4DD) in width.
ANATOMICAL STRUCTURES OF THE RIGHT EYES PERIPHERAL
RETINA
The vortex veins and ampullae will serve as very good landmarks
for an examiner. These vortex ampullae and veins represent the
equator of the eye. They are very important when one wants to
describe retinal defects and their relationship to the rest of the
retina. Vortex veins and ampullae are usually very easily seen in
fair complexioned, light hair and blue eyed individuals. However,
they might blend in with the rest of the retinal pigment background
making them more difficult to delineate. There is always some
pigment migration, in these cases, toward and around the vortex
ampullae and in these cases the pigment migration is the only clue
to the vortex ampullae location.
The long ciliary nerves are your two horizontal landmarks located at
three and nine o'clock. They have a broad base located at the ora
and taper to a somewhat rounded apex approximately at the
equator. The short ciliary nerves are most visible in the superior
and inferior peripheral retina and usually located very near one of
the vortex veins and ampullae. They may run all the way to the ora
or only be seen as a very short whitish to yellow colored structure
that definitely stands out from the rest of the retina
The ora serrata is the point where the choroid and retina end. The
ora will vary in color from black, brown to a felt soft gray. It is not
uncommon to find the retina near it to have a slightly off colored
orange gray appearance known as chorioretinal degeneration. This
can be broken down in to mild, moderate, and severe degeneration.
Regardless how one classifies the degeneration there is little to
worry about and is considered to be benign with no predisposition
to retinal holes or tears
The pars plana, when first seen, is very confusing because in many
patients it looks very much like the rest of the retina in color. It is
usually noticed while looking at the ora serrata and the
degeneration near the ora. Suddenly one finds themselves trying to
determine what they have just discovered. One moment the
pigmented ora is seen then what appears to be normal colored
retina jumps into view. It must be pointed out that you will not see
this structure in every patient unless the pupil is dilated maximally.
It is essential that everyone realizes the primary reason for
performing a dilated examination of the peripheral retina is to
detect potential retinal detachments (RD). There are of course other
findings a dilated retinal examination can reveal, but RD are the
primary reason. Retinal detachments constitute a separation of the
sensory retina from the underlying retinal pigment epithelium, (RPE)
due to the accumulation of liquefied vitreous fluid in that potential
space. Most RD are the result of one or more retinal holes that allow
passage of fluid between the sensory retina and the RPE. The RD
may be quite flat or become large and bullous protruding into the
vitreous cavity and undulate with eye movements. The bullous
detachment is an active detachment with sloping visual field
margins. Detachments may occur anywhere in the retina where a
hole or tear is located. Superior detachments are potentially more
serious than inferior ones because of gravity. They may rapidly
extend inferior to detach the macula with loss of central vision
which may be permanent, even if surgery is successful in restoring
the retina to its proper position. Older or small incomplete RD will
leave a pigmented line along their borders. These flat peripheral RD
if suspect must be sclerally indented to differentially them from a
flat retinoschisis. Dr. James Hunter refers to these pigmented
(demarcation) lines as danger lines. If not correctly diagnosed an
the patient later develops a RD the doctor is in danger of being
sued.
Symptoms associated with a RD may be minimal to no symptoms at
all. Frequently the patient complains of light flashes, dark floating
specks, and a curtain-like defect in their field of vision. Patients with
these complaints must be seen promptly. Most retinal detachments
are associated with retinal holes and the holes, in turn, are the
result of vitreous traction. Vitreous traction may cause a classic
horseshoe tear or retinal break making the patient more
predisposed to developing a retinal detachment.
BENIGN PERIPHERAL RETINA FINDINGS
1.) It is common to fine cystoidal degeneration near the ora serrata.
It is found in most all adult eyes and increases with age. Though
considered to be benign by itself it is involved with some other
conditions that are not so benign. These will be discussed later
(retinoschisis ).
2.) Pavingstone or Cobblestone degeneration is found in about 27%
of the population. It is considered by some not to be a degeneration
but a retinal defect that has been present since birth. Though the
retina appears atrophied the condition is more like that of a
coloboma or failure of that part of the retina to develop. It is most
often found in the inferior-temporal part of the retina between the
ora and the equator. Dr. Alexander, however, classifies this as a
degeneration seen in patients over the age of 20 years.
3.) Reticular pigmentary degeneration is a common finding in the
peripheral fundi of older patients. When these areas are indented
one usually finds an area of honeycomb degeneration present
deeper in the retina.
4.) Equatorial drusens are another common finding that is very
interesting and are usually only note worthy. They are usually of the
soft fluffy type and as long as they do not involve the macula foveal
area they seldom cause vision problems. What are drusens? The
RPE functions in several ways. It forms an outer blood-retina
barrier, works in the transport of metabolites between the
choriocapillaris and the retina, functions to eliminate damaged and
discarded photoreceptor outer segments and works to prevent the
development of choroidal neovascular nets. When the RPE cells are
not functioning properly they produce an extracellular material such
as collagen an basement membrane material, which is deposited
onto Bruch's membrane. The resulting deposits are called drusens
which are composed of mucopolysaccharides and lipids. One might
think of drusens as kind of garbage dump resulting from a not too
healthy RPE. Drusens of some form are found in over 70% of
patients over 50 years and do not negatively affect all eyes.
5.) Choroidal or pigmentary degeneration, are one and the same
and is located at or near the ora. Another peripheral retinal
condition that is only note worthy.
RHEGMATOGENOUS PERIPHERAL CONDITIONS
1.) Lattice degeneration, (Non-pigmented & pigmented lattice)
holes within this degeneration are the result of extreme thinning of
the retinal tissue.
Pigmented lattice like degeneration aligned with a peripheral vessel.
A.) Retinal erosion (non-pigmented) 
B.) Snail track (non-pigmented) with holes and tears

2.) Retinoschisis - bullous & flat
A.) Acquired or Reticular schisis

B.) Congenital or Typical Schisis

3.) White Without Pressure
4.) Vitreoretinal Adhesions (Retinal Tag)
5.) Snowflake Vitreoretinal Degeneration once was thought to be a
benign finding. However, recent findings classify it as an inherited
condition which may be related to retinitis pigmentosa. The retinal
layers involved included the inner retinal layers. The condition
progresses through four stages and may develop retinal breaks,
retinal detachments, or neovascularization of the peripheral retina
may occur.
Rhegmatogenous means to tear or break. In these cases it is
related to retinal areas of degeneration that may develop tears,
breaks or holes leading to retinal detachments. The reason dilation
and peripheral retinal examinations are so very important is
detecting conditions that may lead to retinal detachments or
patients who have retinal detachments. It is somewhat surprising
that about 50% of all patients with retinal detachments are totally
asymptomatic.
Detachments not secondary to a retinal holes tears or breaks are
called nonrhegmatogenous detachments and are caused by primary
choroidal tumors, inflammation, or metastatic lesions. The tumors
that commonly produce these "secondary" detachments are
choroidal melanomas or metastatic carcinomas from the breast,
lung, and prostate which migrate to the choroidal vascular system.
LATTICE DEGENERATION: The clinical appearance is that of
circumferentially oriented, sausage-shaped areas. Located at or
between the equator and the ora serrata, of increased atrophic
thinning retina and increased retinal pigment epithelium (RPE)
pigmentation. The vitreous over lying this area is liquefied and the
vitreous membrane is firmly attached. Radial white (lattice) lines
represent sclerosed retinal vessels and along with these may be
overlaying vitreoretinal (glitter). The majority of the lesion has a
grayish white appearance. Holes which occur within lattice areas are
either the result of continued thinning of the retinal tissue or
secondary to vitreoretinal adhesions which are associated with the
lesion. Tears occur as a result of vitreoretinal adhesions and traction
at the borders of the primary lesions. Tears and holes have a
deeper reddish color than the surrounding lesion or retina which
helps make a differential diagnosis.
Other atrophic equatorial retinal changes are "retinal erosion" and
"snail tracks" which are grayish in color and most likely variations of
lattice degeneration. They do lack the pigmentation, but have many
of the other characteristics of lattice degeneration. A very good
term for these areas of atrophy is "lattice like" degeneration".
RETINOSCHISIS: There is a congenital "flat"("typical" according to
Dr. Alexander, probably to differentiate it from Congenital
Hereditary Retinoschisis) retinoschisis which is the splitting of the
nerve fiber layer at the outer plexiform layer. Dr. Alexander
believes the "flat" schisis represents an advanced form of cystoid
degeneration. Then there is the acquired "bullous" ("reticular"
according to Dr. Alexander) form of retinoschisis. The acquired form
if not the most common is certainly the most eye-catching looking
like a water blister protruding inwardly toward the inside of the eye.
Some believe it is actually a complication occurring secondary to
peripheral cystoid retinal degeneration. Clinically, degenerative
acquired retinoschisis appears as a ballooning "bullous" retinal
elevation with smooth sharp borders. The cavity of "bullous" schisis
is thought to be filled with hyaluronic acid a mucopolysaccharide.
Hyaluronic acid is typically very viscous, a component of the
vitreous, which would explain the taut appearance of the schisis.
The condition is the result of splitting of the inner limiting
membrane and the outer nuclear layer of the retina. The
neuroepithelium remains intact, but the inner layer becomes
stretched and thinned because of the vitreous traction. Vitreoretinal
"glitter" which is sometimes referred to as "snowflakes" and
sclerosed whitish colored retinal vessels are found on its inner
surface. These vessels give it a reticular appearance and are
common findings on the inner layer. Retinal holes or breaks may
occur in either the inner or outer layers; holes in just the inner layer
are basically note worthy, while holes in the outer layer are of
greater concern, e.g., retinal detachments are more likely. Superior
bullous retinoschisis with inner and outer layer breaks or a schisis
that is already posterior to the equator should be referred for a
second opinion. Because of the splitting of the retina the field
defects are absolute and have steep borders. Bullous retinoschisis
do not undulate (wave) with eye movements like a retinal
detachment. Holes in the inner layer are not treated because they
are simply openings into the cystic cavity, but outer layer holes may
require treatment, since they could facilitate the formation of a
retinal detachment. Cases with holes in both layers should be
referred for consultation and possible treatment.
VITREORETINAL ADHESION (RETINAL TAG): These are areas of
atypical retinal tissue to which the vitreous membrane has become
firmly attached. The condition may be either congenital or acquired,
in that the atypical retinal tissue may have been present from birth
or resulted from a small area of inflammation or trauma. With
vitreous age changes, the vitreous body liquefies and shrinks,
causing a strong physical tugging on this area of retina. Two things
may happen, either a small plug of retina will pull free releasing the
physical tension or the retina will tear. If a plug of retina pulls free
releasing the tension the likelihood of a retinal detachment is very
small. However, if the retina tears the odds of a retinal detachment
then or in the future are greatly increased. These areas should be
monitored every 2 months, then 4 months and every 6 months,
however, tears should either be referred or monitored more closely.
Photographs of these areas are a great aid in monitoring patients.
Patient education in all rhegmatogenous cases is a must . It is
extremely important and should always be recorded in the patients
record that the patient has been educated regarding symptoms
associated with RD. Also, record when you want to see them again
then followed this up with a recall card. Patients should be told to
return anytime they experience any visual changes; increased
number of floaters, spots, flashes of light, veil like curtain affecting
peripheral vision or any change of concern.
In the event of any of these symptoms and negative dilated fundus
examination findings you must always check for "Shafer's Sign".
The presence of pigment granules in Berger's space or anterior
vitreous indicates there is a retinal break or detachment. Pigment
granules may be present if the patient has had previous ocular
surgery, but you cannot allow that to influence the need to go back
and take another look.
Dr. James E. Hunter conducted a peripheral retina study on 1000
patients. All patients were dilated and B.I.O. examinations
performed. The break down of the 1000 patients is as follows:
Caucasians = 692
African Americans = 308
1.) Lattice degeneration (all types)
Present in 3.5% of the Caucasians

Present in 7.0% of the African Americans

2.) Retinoschisis (all types)
Present in 0.5% of the Caucasians 
Present in 1.0% of the African Americans

3.) White without pressure
Present in 2.5% of the Caucasians 
Present in 23% of the African Americans

In all conditions African Americans had a higher incidence, even
though there were more than twice the number of Caucasians in the
study. The condition of white without pressure might be
understandable for it is much easier seen in a darkly pigmented
retinas. However, it is still hard to accept that African Americans
would have such a significantly higher incidence of white without
pressure than Caucasians.
You should be familiar with the following slides and the description
information plus the Manual Handout on peripheral retina.
1.) Histoplasmosis - Presumed Ocular Histoplasmosis Syndrome
(POHS) has a triad of retinal involvement ( a.) peripheral atrophic
retinal spots-punched out lesions (b.) peripapillary choroidal
atrophy (c.) exudative maculopathy secondary to choroidal
neovascular membranes. the condition is fungal related an
associated with birds. The condition is a (hypersensitivity reaction)
with the organisms reaching the choroidal circulation during a
systemic involvement. Active histoplasmosis does not produce the
massive proliferation of cells within the vitreous body like
toxoplasmosis. See color plates 79 through 82 in Dr. Alexander's
book. (Monitor closely, Amsler Grid)
2.) Choroidal nevus (Benign Choroidal Melanoma)- usually a flat,
grayish-green lesion which varies in size. Overlying drusens and
increase in size tendency with age. Red-free, green filter, is used to
differentiate choroidal from retinal. Up to 2DD in size document and
follow. 2DD to 5DD be suspicious with special testing and careful
follow-up care. Over 5DD assume malignancy until proven
otherwise. See color plate 98 in Dr. Alexander's book. (Note those 2
1/2 to 5 disc diameters or larger should be monitored more closely;
more likely to develop into malignant tumors).
3.) Congenital Hypertrophy of the Retinal Pigment Epithelium
(CHRPE), also know as a Halo nevus, is a benign condition. However,
there is a relative scotoma which corresponds to the area of
hypertrophy when tested with threshold fields. With increase in age
the scotoma becomes more absolute because of atrophy of the
underlying chorioretina and overlying sensory retinal degeneration.
See color plates 95 & 96 and pages 376-377 in Dr. Alexander's
book.
4.) Horseshoe tears - are a direct result of vitreoretinal adhesions.
This break coupled with the liquefied vitreous greatly increases the
risk for a rhegmatogenous retina detachment. See color plate 109
in Dr. Alexander's book. It is not a horseshoe tear, but is a tear
secondary to vitreoretinal traction. Page 404 has a black and white
photograph of a horseshoe tear. (These tears should be referred).
5.) Toxoplasmosis - is an intracellular protozoan parasite an can be
either congenital or acquired in nature. It is one of the more likely
causes of posterior uveitis in the United States. The most common
route of congenital or maternal toxoplasmosis is exposure of the
mother to cat feces, as the cat is the natural host for the parasite.
The protozoa enters the eye via the circulatory system, then locates
within the nerve fiber layer. The ocular inflammation caused by the
parasite and hypersensitivity reaction is likened to "headlights in the
fog" because the inflammation and lesion has a white central area
seen through a very hazy vitreous filled with cells and debris. See
color plates 83 & 84 plus pages 316 & 317 in Dr. Alexander's book.
6.) Branch Retina Vein Occlusion (BRVO) - has been reported to be
the second most prevalent retinal vascular diseases seen in eyecare
practice. Occurs most frequently at arteriovenous crossings and is
the result of a thickened artery pressing on a thin-walled vein. The
clinical picture can vary depending on the site of the occlusion. The
superior temporal veins are affected most often because there are
more arteriovenous crossings in the superior temporal retina then
elsewhere. The clinical picture is that of dilated tortuous veins, dotblot and flame shape hemorrhages from the site of obstruction out
to the retinal periphery in the sector of the retina drained by the
affected vein. See color plates 34, 38, and 39 in Dr. Alexander's
book.
7.) Metastactic tumors- One cannot determine if a choroidal tumor
is metastatic just by the color, however, they are typically
yellowish-white with deposits of lipofucin. They are usually different
in color from the malignant choroidal melanoma. The prognosis is
relatively poor in malignant choroidal melanomas and metastatic
tumors. Regardless of the final outcome, all suspect uveal
melanomas deserve a consultation with a retinal oncologist for this
is a vision and life threating condition. See color plates 99 and 100
in Dr. Alexander's book. (If that's what you think you have, refer).
8.) Disciform macular degeneration (Wet "Exudative"- Age Related
Macular Degeneration (ARM)- has long been associated with
drusens even though the neovascular growth occurs away from the
visible drusens, within the RPE and Bruch's membrane. The
presence of soft fluffy drusens, really choroidal infiltrates or RPE
detachments, should increase the doctor's suspicion. Choroidal
neovascularization occurs as the result of disruption in the RPE and
Bruch's barrier. The new vessels from the choriocapillaris grow up
through the disruption in Bruch's. The neovascularization may (1)
leak, creating an RPE detachment or sensory detachment, (2)
hemorrhage or (3) form a disciform scar. All hard exudates (Coat's
response) in the macula area in the absence of retinal vascular
disease should alert you to the possibility of choroidal neovascular
nets. Patients with suspected choroidal neovascular membranes or
other signs of wet ARM should have fluorescein angiography
performed within three days. It has been shown that expertly
placed laser photocoagulation applied in a timely manner reduces
the risk of severe vision loss in patients with wet ARM. See color
plates 64 through 71 in Dr. Alexander's book.
9.) Drusens of the optic disc (Buried Drusen Of the Optic Nerve
Head)- can create a diagnostic dilemma and does not represent a
benign, nonprogressive condition. They can make the differential
diagnosis of papilledema very difficult. Nerve head drusens are
congenital and have no correlation to retinal drusens. They are
calcium-like deposits which are confined anterior to the lamina
cribrosa. The calcific deposits can compromise the nerve fibers and
vascular supply, leading to visual field defects and peripapillary
hemorrhages. Intervention therapy is currently not available to
prevent the associated nerve fiber loss or hemorrhages. See color
plates 11 and 12 in Dr. Alexander's book.
10.) Coats' disease is a exudative retinopathy resulting from
telangiectasias of the retinal vessels. Telangiectasia is a Greek term
meaning "dilation of capillaries and sometimes of terminal arteries
producing an angioma of macular appearance." Coats' disease
usually occurs unilaterally in the first to second decades of life. Its
seen approximately four times more often in males than females,
yet despite the fact that the telagiectasias are congenital, the
condition usually is not discovered until the first or second decades.
Over time the congenital abnormal vessels become altered leading
to leakage, degeneration and development of hard exudates.
Unless the condition is caught early it usually leads to parafoveal
and perifoveal exudates, retinal hemorrhages, neovascularization
and loss of vision. Dr. Alexander describes the following
characteristics: 1.) Occurs unilaterally in 90 percent of patients 2.)
Most often in males under age 20 years 3.) No genetic association
4.) No systemic disease association 5.) Irregular dilatation of retinal
vessels with a wide variation in clinical presentation 6.) May
progress to intraretinal and subretinal exudate accumulation with a
poor visual prognosis. Dr. Alexander's suggested management in
suspected patients is fluorescein angiography to determine if the
lesions that are threatening vision are treatable by
photocoagulation. The earlier the disease is detected and
appropriate treatment administered, the better the prognosis.
11.) Central Areolar Choroidal Dystrophy (CACD) has been
described as having autosomal dominate and autosomal recessive
inheritance patterns and some are sporadic cases. The earliest
fundus changes are bilateral RPE mottling in and around the
macula. There is progressive atrophy of the RPE and choriocapillaris
within a sharply outlined zone around the fovea. Clinically the
appearance is one of atrophy of the choriocapillaris loss of the RPE
and atrophy of the sensory retina.
The main symptom of this condition is reduced vision from age 30
to 40 with a slow progression to 20/200 or worse with aging. Loss
of color vision and central scotomas are related to the degree of
impairment. Peripheral vision remains intact and there is no
complaint of night blindness.
12.) Macular holes have a somewhat confusing etiology. It is
generally considered that any condition that precipitates cystoid
macular edema may result in the development of a macular hole.
The presence of a posterior vitreous detachment (PVD) may lead to
tugging at the macula causing the formation of a macular hole has
been suggested.
Macular holes are clinically still divided into two categories , full
thickness and lemellar holes. The classic full thickness hole is
usually 1/4 to 1/3 disc diameters in size. It has a reddish color
surround by a grayish edematous appearing cuff of retinal tissue
and there are yellowish deposits in the base of the hole. The full
thickness hole will cause significant reduction in visual acuity and a
central scotoma. Lamellar holes do not have the characteristic
reddish color of a full thickness hole. The patient with a lamellar
hole will present with slightly reduced vision and metamorphopsia.
For suspected macular holes that appear questionable or uncertain
in nature or do not lend themselves to a clear diagnostic
observation, consider the Watzke-Allen test. A vertical beam of light
is presented to the fovea, slit lamp beam with a fundus lens or a
direct ophthalmoscope. Ask the patient if the line is uniform or
broken in the center-patients with macular compromise report a
broken line. Those with a pseudohole might report the line as
complete, but centrally distorted. See color plates 77 & 78 in Dr.
Alexander's book.
13.) Papilledema is defined as optic nerve head edema secondary to
increased intracranial pressure. The main cause of optic nerve head
swelling is blockage of the axoplasma transport and the blockage
occurs at the lamina cribrosa. The optic nerve head can swell to the
extent where it is extended forward into the vitreous as well as
laterally. This lateral swelling causes the retina to buckle inward at
the temporal aspect of the optic nerve head. The buckling is know
as Paton's folds and results in a enlarged blind spot. The acute rise
of intracranial pressure results in papilledema, sometimes called a
choked disc, flame shape hemorrhages, engorged veins, and
cotton-wool soft exudates. There are most certainly varying degrees
of papilledema depending on the what is causing the rise in
intracranial pressure and what stage in this compromise the
clinician sees the patient.
Symptoms will vary depending the degree of optic nerve head
swelling and the how long the condition has been present.
Headaches might start out like any common headache but as the
condition reaches the chronic stage they may be severe enough to
cause vomiting. In the chronic stage transient loss of or blurring of
vision may occur lasting 5 to 30 seconds. I must say it sure seems
longer than 30 seconds. There are no signs of optic nerve
conduction defects such as the Marcus Gunn pupil (afferent
pupillary defect) APD or color desaturation until optic atrophy
occurs. Papilledema should be considered a life treating condition
and any patient with suspect optic nerve head edema should be
referred to a neurologist who must run either a CAT scan or MRI or
both.
OTHER SLIDES WHICH WERE PRESENTED
14.) Retinitis pigmentosa
15.) Advanced Glaucoma
16.) Drusens of the macula
17.) Melanocytoma
18.) Medullated nerve fibers
19.) Bear tracks
20.) Bergmeister's papilla
21.) Staphyloma
22.) Coloboma of nerve head
23.) Branch artery occlusion