This document provides information on the anatomy, physiology and pathologies of the sclera. It begins with a description of the layers and structures of the sclera. It then discusses specific conditions like episcleritis, scleritis and staphyloma. Episcleritis is a benign inflammation of the outer layer of the sclera. Scleritis is a potentially serious inflammation of the inner layers that can be associated with autoimmune diseases. Staphyloma is a bulging of a weakened sclera that allows underlying tissues to protrude out. Causes like osteogenesis imperfecta are also mentioned.

1. DR YOGITA CHAURASIA
DOMS, DNB, FICO, MRCS
ASSISSTANT PROFESSOR OPHTHALMOLOGY

2. ANATOMY
Sclera forms the posterior five-sixth opaque
part of the external fibrous tunic of the
eyeball.
Its whole outer surface is covered by Tenon’s
capsule. In the anterior part it is also covered
by bulbar conjunctiva.
Its inner surface lies in contact with choroid
with a potential suprachoroidal space in
between.
.

3. ANATOMY
• Sclera is thickest posteriorly (1 mm)
and gradually becomes thin when
traced anteriorly. It is thinnest at the
insertion of extraocular muscles (0.3
mm).
• Lamina cribrosa is a sieve-like
sclera from which fibres of optic
nerve pass
In its anterior most part near the
limbus there is a furrow
which encloses the canal of Schlemm

4. ANATOMY
• Apertures. Sclera is pierced by three sets of
apertures
1. Posterior apertures are situated around the optic
nerve and transmit long and short ciliary nerves
and vessels.
2. Middle apertures (four in number) are situated
slightly posterior to the equator; through these
pass the four vortex veins (vena verticosae).
3. Anterior apertures are situated 3 to 4 mm away
from the limbus. Anterior ciliary vessels and
branches from long ciliary nerves pass through
these apertures.

5. ANATOMY
Microscopic structure.
1. Episcleral tissue. It is a thin, dense
vascularised layer of connective tissue which
covers the sclera proper.
2. Sclera proper. It is an avascular structure
which
consists of dense bundles of collagen fibres. The
bands of collagen tissue cross each other in all
directions.
3. Lamina fusca. It is the innermost part of sclera
which blends with suprachoroidal and supraciliary
laminae of the uveal tract. It is brownish in colour
.

6. 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,
Twice as common in women than men.

7. EPISCLERITIS
• Etiology
1. Idiopathic. Exact etiology is not known in many cases.
2. Systemic diseases associated with episcleritis, include gout, rosacea, psoriasis and connective
tissue diseases.
3. Hypersensitivity reaction to endogenous tubercular or streptococcal toxins is also reported.
4. Infectious episcleritis may be caused by herpes zoster virus, syphillis, Lyme disease and
tuberculosis.

8. EPISCLERITIS
Histologically, there occurs localised lymphocytic
infiltration of episcleral tissue associated with
oedema and congestion of overlying Tenon’s
capsule
and conjunctiva

9. EPISCLERITIS
Symptoms. Episcleritis redness, mild ocular
discomfort described as gritty, burning or foreign
body sensation/ mild photophobia and lacrimation/
Asymptomatic
• Simple episcleritis is characterised by sectorial
(occasionally diffuse) inflammation of episclera.
The engorged episcleral vessels are large and run
in radial direction beneath the conjunctiva
• Nodular episcleritis is characterised by a pink
or purple flat nodule surrounded by injection,
usually situated 2–3 mm away from the limbus.
The nodule is firm, tender, can be moved
separately from the sclera and the overlying
conjunctiva also moves freely.

10. EPISCLERITIS
Differential diagnosis
• Simple episcleritis- conjunctivitis.
• Nodular episcleritis –inflamed pinguecula,
swelling and congestion due to foreign body
lodged in bulbar conjunctiva and, very rarely
with scleritis.
Treatment
1. Topical NSAIDs, e.g., ketorolac 0.3% may be
useful.
2. Topical mild corticosteroid eyedrops e.g.,
fluorometholone or loteprednol instilled 2–3
hourly, render the eye more comfortable and
resolve the episcleritis within a few days.
3. Topical artificial tears e.g., 0.5% carboxy
methyl

11. EPISCLERITIS
Treatment
1. Topical NSAIDs, e.g., ketorolac 0.3% may be
useful.
2. Topical mild corticosteroid eyedrops e.g.,
fluorometholone or loteprednol
3. Topical artificial tears e.g., 0.5% carboxy methyl
cellulose have soothing effect.
4. Cold compresses applied to the closed lids may
offer symptomatic relief from ocular discomfort.
5. Systemic nonsteroidal anti-inflammatory drugs
(NSAIDs) such as flurbiprofen (300 mg OD),
indomethacin (25 mg three times a day)

12. SCLERITIS
Scleritis refers to a inflammation of the sclera proper.
It usually occurs in elderlypatients (40-70 years)
females more than the males
Scleritis can be classified as follows:
A. Non-infectious scleritis
I. Anterior scleritis (98%)
a. Non-necrotizing scleritis (85%)
1. Diffuse
2. Nodular
b. Necrotizing scleritis (13%)
1. with inflammation
2. without inflammation (scleromalacia perforans)
II. Posterior scleritis (2%)
B. Infectious scleritis

13. SCLERITIS-
• Overall about 50% cases of scleritis are associated with some systemic diseases, M/C CTD
1. Autoimmune collagen disorders, especially rheumatoid arthritis, is the most common association. About
0.5% of patients (1 in 200) suffering from seropositive rheumatoid arthritis develop scleritis. Other - Wegener’s
granulomatosis, polyarteritis nodosa (PAN), systemic lupus erythematosus (SLE) and ankylosing spondylitis.
2. Metabolic disorders like gout and thyrotoxicosis
3. Some infections, herpes zoster ophthalmicus, chronic staphylococcal and streptococcal
4. Granulomatous diseases like tuberculosis, syphilis, sarcoidosis, leprosy
5. Miscellaneous conditions like irradiation, chemical burns, Vogt-Koyanagi-Harada syndrome, Behcet’s,
rosacea
6. Surgically induced scleritis (SIS) is a rare complication of ocular surgery. It occurs within 6 months
7. Idiopathic.

14. SCLERITIS
Histopathological changes are that of a chronic
granulomatous disorder characterised by fibrinoid
necrosis, destruction of collagen together with
infiltration by polymorphonuclear cells,
lymphocytes,
plasma cells and macrophages. The granuloma
is
surrounded by multinucleated epithelioid giant
cells
and old and new vessels, some of which may
show
evidence of vasculitis.

15. SCLERITIS
■■Pain: Patients complain of moderate to severe pain
which is deep and boring in character and often
wakes the patient early in the morning. Ocular pain
radiates to the jaw and temple.
■■Redness may be localized or diffuse.
■■Photophobia and lacrimation may be mild to
moderate.
■■Diminution of vision may occur occasionally

17. SCLERITIS
Non-necrotizing anterior diffuse
scleritis.
commonest variety, characterised by
widespread
inflammation involving a quadrant or more of
the
anterior sclera. The involved area is raised and
salmon pink to purple in colour
• Topical steroid eyedrops
• Systemic indomethacin 75 mg twice a day
until
inflammation resolves.

18. SCLERITIS
Non-necrotizing anterior nodular scleritis. It is
characterised by one or two hard, purplish elevated
immovable scleral nodules, usually situated near
the limbus (Fig. 7.4). Sometimes, the nodules are
arranged in a ring around the limbus (annular
scleritis).

19. SCLERITIS
Anterior necrotizing scleritis with
inflammation.
It is an acute severe form of scleritis characterised
by
intense localised inflammation associated with
areas
of infarction due to vasculitis. The affected
necrosed area is thinned out and sclera becomes
transparent and ectatic with uveal tissue shining
through it. It is usually associated with anterior
uveitis.
Topical steroids
• Oral steroids on heavy doses, tapered slowly.
• Immunosuppressive agents like methotrexate
or cyclophosphamide
• Subconjunctival steroids are contraindicated
• Surgical treatment, in the form of scleral patch graft

20. SCLERITIS
Anterior necrotizing scleritis without inflammation
(scleromalacia perforans). This specific entity typically
occurs in elderly females usually suffering from
longstanding
rheumatoid arthritis. It is characterised by
development of yellowish patch of melting sclera
(due to obliteration of arterial supply); which often
together with the overlying episclera and conjunctiva
completely separates from the surrounding normal
sclera. This sequestrum of sclera becomes dead white
in colour, which eventually absorbs leaving behind
it a large punched out area of thin sclera through
which the uveal tissue shines. Spontaneous
perforation is extremely rare.

21. SCLERITIS
• Posterior scleritis.
It is an inflammation involving the sclera behind
the
equator. The condition is frequently
misdiagnosed.
It is characterised by features of associated
inflammation of adjacent structures, which
include:
exudative retinal detachment, macular oedema,
proptosis and limitation of ocular movements.

22. SCLERITIS
• Infectious scleritis
• Infectious scleritis accounts for 5–10% of all
cases.
• In the early stage diagnosis becomes difficult as
presentation is similar to as non-infectious
scleritis.
• Scleritis with purulent exudates or
infiltrates should raise the suspicion of an
infectious etiology.
• Formation of fistulae, painful nodules,
conjunctival
and scleral ulcers are usually the signs of
infectious scleritis.
• Antimicrobial therapy, both with topical and oral
agents is required in an aggressive manner.
• Surgical debridement is found useful by debulking
the infected scleral tissue and also facilitating the
effect of antibiotics STEROIDS MAY WORSEN THE INFECTIVE SCLERITIS

23. SCLERITIS
COMPLICATIONS: are quite common with necrotizing
scleritis
and include sclerosing keratitis, keratolysis,
complicated cataract and secondary glaucoma.

24. SCLERITIS
SYSTEMIC INVESTIGATIONS
1. TLC, DLC and ESR.
2. Serum levels of complement (C3),
immune
complexes, rheumatoid factor, antinuclear
antibodies and L.E cells for an
immunological
survey.
3. FTA–ABS, VDRL for syphilis.
4. Serum uric acid for gout.
5. Urine analysis.
6. Mantoux test.
7. X-rays of chest, paranasal sinuses,
sacroiliac jointand orbit (to rule out foreign
body especially inpatients with nodular
scleritis).

25. 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.
• Staphylomas (diagrammatic depiction) A,
Intercalary; B, Ciliary; C, Equatorial; D, Posterior
osteogenesis imperfecta. Its other causes are
Marfan’s syndrome, Ehlers-Danlos syndrome,
pseudoxanthoma elasticum, buphthalmos, high
myopia and healed scleritis.

26. BLUE SCLERA
• osteogenesis imperfecta
• Marfan’s syndrome
• Ehlers-Danlos syndrome,
• pseudoxanthoma elasticum
• Buphthalmos
• High myopia
• healed scleritis.