I.
PATHOLOGIC RESPONSES OF THE CONJUNCTIVA
Some features of conjunctival disorders seen in slit lamp or during examination with
side illumination may be specific for various types of conjunctival diorders. They
include:
Conjunctival hyperemia – It is produced by dilation of blood vessels and is classified
as superficial (Fig.1) (dilation of conjunctival vessels seen as a reddish flush of the
conjunctiva) and deep (dilation of ciliary of episcleral vessels seen as a bluish
subconjunctival flush). Superficial hyperemia disappears after instillation of
phenylephrine drops or touching with glass rod. The extent and location of
conjunctival hyperemia depends on underlying pathology. Diffuse, superficial
hyperemia of both the bulbar and tarsal conjunctivae is typical of conjunctivitis
(Fig.2). It is usually the most
pronounced in viral conjunctivitis. Circumcorneal
conjunctival hyperemia of deep vessels that extend 1 to 3 mm out from the limbus,
without significant hyperemia of the bulbar superficial conjunctival vessels is seen in
iritis and acute glaucoma. Diffuse or circumscribed areas of both superficial and deep
hyperemia involving 20 to 100% of the bulbar conjunctiva without hyperemia of the
tarsal conjunctiva is typical of episcleritis and scleritis.
Fig. 1 Superficial conjunctival hyperemia in bacterial conjunctivitis
Fig. 2 Significant conjunctival hyperemia in epidemic keratoconjunctivitis
Conjuntival vessels tortuosity – General tortuosity of all, small conjunctival vessels
without any inflammatory signs is typical feature of Fabry disease, ataxia
telangiectasia (Louis Bar syndrome), mucolipidosis I and blood hyperviscosity
disorders. (Fig.3)
Dilated large vessels are seen in Sturge-Weber syndrome and
especially in carotid-cavernous sinus fistula and dural shunts (corkscrew, aterialized
venous vessels). (Fig. 4 and 5) Segmental dilatation and tortuosity of vessels can be
seen as a secondary signs of various conjunctival disorders including melanocytic
lesions, choristomas, epithelial cysts, pterygium and pinguecula.
Fig. 3 Vascular tortuosity in ataxia telangiectasia
Fig. 4 Dilated large conjunctival vessels in Sturge-Weber syndrome
Fig. 5 Corkscrew, aterialized venous vessels in carotid-cavernous sinus fistula
Telangiectasies – These vascular lesions are segmental alterations of the conjunctival
vessels structure with aneurysmal dilatation. They are typical signs of Goldenberg
syndrome (galactosialidosis), Rendu-Osler-Weber syndrome and ataxia telangiectasia
(Louis Barr syndrome).(Fig. 6) Very rarely they can be found in lymphangiectasia.
Conjunctival telangiectasies have been also described in morphea coup de saber
syndrome (congenital linear groove in scalp or forehead skin spreading to the lids and
eye). (1)
Fig. 6 Conjunctival telangiectasia in ataxia telangiectasia
Conjunctival haemorrhages – Can be found in conjunctivitis (the most frequently in
viral – picornaviral and herpetic infections), after trauma, rise of central venous
pressure (after the birth, after the activity involving Valsalva type maneuvers, after a
seizures) and disorders with thrombocytopenia.
Edema – It is caused by edematous thickening of conjunctiva. Gross edema with
ballooning of the conjunctiva often leading to its prolapse between the eyelids is
known as chemosis. It can be associated with allergy, trauma (including surgery),
acute infections and orbital inflammations.
Papillae - They present as elevated, polygonal, hyperemic areas separated by pale
channels with central vessel erupting into a spoke-like pattern. The connective tissue
septa that anchor the epithelium to the deeper collagenous tissue limits the size of
papilla to less than 1mm. (Fig. 7) Papillae are non specific sign occurring in any kind
of inflammation (mainly in bacterial and allergic).
Fig. 7 Conjunctival papillae in bacterial conjunctivitis
Giant papillae - They are formed by the disruption of the connective tissue septa and
coalescence of 2-4 papillae. Its size is greater than 1 mm. (Fig. 8) They are usually
manifestation of ocular allergy not infections, typically found in vernal conjunctivitis,
atopic keratoconjunctivitis, and giant papillary conjunctivitis (reaction to contact
lenses, sutures, prostheses).
Fig. 8 Giant papillae in giant papillary conjunctivitis
Follicles - There are numerous, smooth, yellowish elevation of the conjunctiva, 2-4
mm of diameter, similar to small grain of rice, with no vessels inside them. (Fig. 9)
Follicles represent hyperplasia of subconjuntival lymphoid tissue. They are common
presentation of viral (acute inflammation lasting less than 3 weeks), chlamydial
conjunctivitis (chronic inflammation with exacerbation lasting more than 3 weeks)
and can be found in benign lymphoid hyperplasia (folliculosis), Parinaud’s
oculoglandular
syndrome
and
in
toxic
reactions
(medications,
molluscum
contagiosum).
Fig. 9 Follicles in inclusion conjunctivitis in adolescent
Membranes or pseudomembranes - True membranes develop when conjunctival
epithelium becomes necrotic and firm adhesions are formed between necrotic cells and
the overlying coagulum. Membrane removal leaves raw, bleeding surface.
Pseudomembranes are formed by inflammatory cells and exudates that are loosely
adherent to the underlying epithelium and can be peeled away without bleeding and
damage to ocular surface. Membranes and pseudomembranes
manifestations
of
beta
hemolytic
streptoccocal
are usually
conjunctivitis,
herpetic
keratoconjunctivitis, chlamydial conjunctivitis in newborns, ligneous conjunctivitis,
candida infections and can be found in diphtheria, Stevens-Johnson syndrome and
after chemical burns.
Micro-pannus - It is subepithelial proliferation of fibrovascular tissue from limbus
into the cornea that extends 1-2 mm beyond the normal vascular arcade. (Fig.10) It
can be found in chlamydial, conjunctivitis, staphylococcal blepharoconjunctivitis,
vernal conjunctivitis and after contact lens wear.
Fig. 10 Micro-pannus in staphylococcal blepharoconjunctivitis
Gross-pannus – Extends more than 2 mm beyond the normal vascular arcade.
Superior pannus is typical manifestation of trachoma (Fig. 11) but can be occasionally
seen in
staphylococcal
blepharitis, herpetic
keratoconjunctivitis and in rosacea.
keratoconjunctivitis, atopic
Fig. 11 Gross-pannus in trachomatous keratoconjunctivitis. (by courtesy of dr.
Mohamed Higazy, Cairo, Egypt)
Conjunctival scarring – It can occur in a variety of inflammations (infectious,
immunological, allergic, posttraumatic). Raw and denuded surfaces of conjunctiva can
adhere and scar leading to symblepharon and shortening of the conjunctival fornices.
The most pronounced scarring occurs in trachoma, chemical burns and in erythema
multiforme, Stevens-Johnson and toxic epidermal necrolysis.