Showing posts with label sclera. Show all posts
Showing posts with label sclera. Show all posts

Wednesday, December 29, 2010

Staphyloma

Staphyloma refers to a localised bulging of weak and
thin outer tunic of the eyeball (cornea or sclera), lined
by uveal tissue which shines through the thinned
out fibrous coat.
Types
Anatomically it can be divided into anterior,
intercalary, ciliary, equatorial and posterior
staphyloma

1. Anterior staphyloma. An ectasia of psuedocornea
(the scar formed from organised exudates and
fibrous tissue covered with epithelium) which
results after total sloughing of cornea, with iris
plastered behind it is called anterior staphyloma

2. Intercalary staphyloma. It is the name given to
the localised bulge in limbal area lined by root of iris
(Figs. 6.8A and 6.9). It results due to ectasia of weak
scar tissue formed at the limbus, following healing of
a perforating injury or a peripheral corneal ulcer. There
may be associated secondary angle closure glaucoma,

which may cause progression of bulge if not treated.
Defective vision occurs due to marked corneal
astigmatism.

Treatment consists of localised staphylectomy under
heavy doses of oral steroids.
3. Ciliary staphyloma. As the name implies, it is the
bulge of weak sclera lined by ciliary body. It occurs
about 2-3 mm away from the limbus (Figs. 6.8B and
6.10). Its common causes are thinning of sclera
following perforating injury, scleritis and absolute
glaucoma.
4. Equatorial staphyloma. It results due to bulge of
sclera lined by the choroid in the equatorial region
(Fig. 6.8C). Its causes are scleritis and degeneration
of sclera in pathological myopia. It occurs more
commonly at the regions of sclera which are
perforated by vortex veins.
5. Posterior staphyloma. It refers to bulge of weak
sclera lined by the choroid behind the equator (Fig.
6.8D). Here again the common causes are pathological
myopia, posterior scleritis and perforating injuries. It
is diagnosed on ophthalmoscopy. The area is

excavated with retinal vessels dipping in it (just like
marked cupping of optic disc in glaucoma) (Fig. 6.11).
Its floor is focussed with minus number lenses in
ophthalmo-scope as compared to its margin.



Episcleritis

Episcleritis is benign recurrent inflammation of the
episclera, involving the overlying Tenon's capsule
but not the underlying sclera. It typically affects
young adults, being twice as common in women than
men.
Etiology
Exact etiology is not known.
It is found in association with gout, rosacea and
psoriasis.
It has also been considered a hypersensitivity
reaction to endogenous tubercular or
streptococcal toxins.
Pathology
Histologically, there occurs localised lymphocytic
infiltration of episcleral tissue associated with oedema
and congestion of overlying Tenon's capsule and
conjunctiva.
Clinical picture
Symptoms. Episcleritis is characterised by redness,
mild ocular discomfort described as gritty, burning or
foreign body sensation. Many a time it may not be
accompanied by any discomfort at all. Rarely, mild
photophobia and lacrimation may occur.
Signs. On examination two clinical types of
episcleritis, diffuse (simple) and nodular may be
recognised. Episclera is seen acutely inflamed in the
involved area.
In diffuse episcleritis, although whole eye may
be involved to some extent, the maximum
inflammation is confined to one or two quadrants
(Fig. 6.2A).
In nodular episcleritis, a pink or purple flat
nodule surrounded by injection is seen, usually
situated 2-3 mm away from the limbus (Fig. 6.2B).
The nodule is firm, tender and the overlying
conjunctiva moves freely.
Clinical course. Episcleritis runs a limited course of
10 days to 3 weeks and resolves spontaneously.
However, recurrences are common and tend to occur
in bouts. Rarely, a fleeting type of disease (episcleritis
periodica) may occur.
Differential diagnosis
Occasionally episcleritis may be confused with
inflamed pinguecula, swelling and congestion due to
foreign body lodged in bulbar conjunctiva and very
rarely with scleritis.

Treatment
1. Topical corticosteroid eyedrops instilled 2-3
hourly, render the eye more comfortable and
resolve the episcleritis within a few days.
2. Cold compresses applied to the closed lids may
offer symptomatic relief from ocular discomfort.
3. Systemic non-steroidal anti-inflammatory drugs
(NSAIDs) such as flurbiprofen (300 mg OD),
indomethacin (25 mg three times a day), or
oxyphenbutazone may be required in recurrent
cases.