Diseases of sclera

anatomy

• Sclera posterior 5/6th opaque part of the external fibrous tunic of the eyeball.

• outer surface }covered by Tenon's capsule.

• anterior part } covered by bulbar conjunctiva.

Its inner surface lies in contact with choroid with apotential suprachoroidal space in between

Thickness of sclera.

• thinner }children and in females Sclera

• thickest} posteriorly (1mm)

• gradually becomes thin when traced anteriorly.

• thinnest } insertion of extraocular muscles (0.3 mm).

• Lamina cribrosa is a sieve-like sclera from which fibres of optic nerve pass.

Apertures of sclera

• Anterior • Anterior ciliary vessels

• Middle• four vortex veins (vena verticosae)

• Posterior• Optic nerve

• Long & short ciliary nerves

Layers of sclera

scle

ra

episclera

Sclera proper

Lamina fusca

thin, dense vascularisedlayer of connective tissue fibroblasts, macrophages andlymphocytes

avascular structure dense bundles of

collagen fibres.

innermost blends with suprachoroidal and supraciliarylaminae of the uveal tract. brownish in colourpresence of pigmented cells.

Inflammations of sclera

• Episcleritis (superficial)

• Scleritis(deep)

episcleritis

• benign recurrent inflammation of the episclera,

• involving the overlying Tenon's capsule

• but not the underlying sclera.

etiology

• Unknown

• Associated with gout/psoriasis/rosacea

• Hypersensitivity reaction to endogenous tubercular or streptococcal toxins.

incidence

• M>f

• Young adults

pathology

• localised lymphocytic infiltration of episcleral tissue

• oedema and congestion of overlying Tenon's capsule and conjunctiva.

symptoms

• by redness,

• mild ocular discomfort described as gritty, burning or

• foreign body sensation

signs

• diffuse episcleritis,

• whole eye maybe involved to some extent,

• the maximum inflammation is confined to one or two quadrants

• nodular episcleritis,

• a pink or purple flat nodule surrounded by injection is seen, 2-3 mm away from the limbus

• The nodule is firm, tender and the overlying conjunctiva moves freely.

Clinical course

• limited course of 10 days to 3 weeks =resolves spontaneously.

• recurrences common and tend to occur in bouts.

• a fleeting type of disease (episcleritis periodica) may occur

DD

• Inflammed pinguecula

• Scleritis

• Fb reaction on bulbar conjunctiva

treatment

• 1.Topical corticosteroid eyedrops 2-3 hourly,

• 2. Cold compresses applied to the closed lids

• 3. Systemic non-steroidal anti-inflammatory drugs

• flurbiprofen (300 mg OD),

• indomethacin (25 mg three times a day), or

• oxyphenbutazone

scleritis

scleritis

• c/c inflmn of sclera proper

• F>m

• Elderly

etiology

• Autoimmune collagen disorders RA(common),Wegener's granulomatosis,PAN, SLE and ankylosing spondylitis.

• Metabolic disorders gout & thyrotoxicosis

• Infections herpes zoster ophthalmicus, c/c staphylococcal and streptococcal infection

• Granulomatous diseases tb,syphilis, sarcoidosis, leprosy

• Miscellaneous conditions irradiation, chemical burns, Vogt-Koyanagi-Harada syndrome, Behcet's disease and rosacea

• Surgically induced scleritis ocular surgery. within 6 month postoperatively.

• Idiopathic

pathology

• infiltration by PMNL , lymphocytes, plasma cells and macrophages

• Fibrinoid necrosis, destruction of collagen

•

• granuloma surrounded by multinucleated epitheloid giant cells

classification

• I. Anterior scleritis (98%)• 1. Non-necrotizing scleritis (85%)

• (a) Diffuse

• (b) Nodular

• 2. Necrotizing scleritis (13%)• (a) with inflammation

• (b) without inflammation (scleromalacia perforans)

• II. Posterior scleritis (2%)

Symptoms

• moderate to severe pain• deep and boring in character and often

• wakes the patient early in the morning .

• radiates to the jaw and temple.

• localised or diffuse redness

• mild to severe photophobia

• lacrimation.

Signs

• 1. Non-necrotizing anterior diffuse scleritis.

• commonest,

• widespread inflammation involving a quadrant or more of the anterior sclera.

• The area is raised and salmon pink to purple in colour

• Non-necrotizing anterior nodular scleritis.

• one or two hard, purplish elevated scleral nodules,

• usually situated near the limbus

• the nodules are arranged in a ring around the limbus (annular scleritis).

• 3. Anterior necrotizing scleritis with inflammation.

• acute severe form of scleritis

• characterised by intense localised inflammation

• associated with areas of infarction due to vasculitis

• necrosed sclera thinned out (sclera becomes transparent and ectatic) with uveal tissue shining through it.

• Anterior uveitis+

• Anterior necrotizing scleritis without inflammation (scleromalaciaperforans).

• elderly females with long-standing RA.

• yellowish patch of melting sclera (due to obliteration of arterial supply);

• with overlying episclera andconjunctiva completely separates from the surrounding normal sclera.

• Eventually absorbs leaving behind it a large punched out area of

• thin sclera through which the uveal tissue shines

• Spontaneous perforation rare

• posterior scleritis.

• the sclera behind the equator.

• frequently misdiagnosed.

• associated inflammation of adjacent structures, • exudative retinal detachment,

• macular oedema,

• proptosis and

• limitation of ocular movements.

complications

• 2’ glaucoma (due to uveitis…)

• Complicated cataract

• sclerosing keratitis,

• keratolysis

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 joint and orbit to rule out foreign body especially in patients with nodular scleritis.

Treatment

• (A) Non-necrotising scleritis• Topical steroid eyedrops and • systemic indomethacin 100 mg daily for a day and then 75 mg daily until

inflammation resolves.

• (B) Necrotising scleritis. • Topical steroids & heavy doses of oral steroids tapered slowly. • In non-responsive cases, immuno-suppressive agents like methotrexate or

cyclophos-phamide• Subconjunctival steroids are contraindicated because they may lead to scleral

thinning and perforation

Blue sclera

Blue sclera

• asymptomatic condition • marked, generalised blue discolouration of sclera due to thinning.

osteogenesis imperfecta. Marfan's syndrome, Ehlers-Danlos syndrome,pseudoxanthoma elasticum, buphthalmos, High myopia and healed scleritis.

staphylomas

staphylomas

• 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.

classification

• Anterior

• Intercalary

• Ciliary

• Equatorial

• posterior

Anterior staphyloma

• Ass. With ectasia of cornea & iris

• Due to perforating corneal ulcer & injury

Intercalary staphyloma

healing of a perforating injury or a peripheral corneal ulcer

to ectasia of weak scar tissue formed at the limbus

localised bulge in limbal area lined by root of iris

• marked corneal astigmatism Defective vision

• 2’angle closure glaucomaprogression of swelling

• Treatment

• localised staphylectomy under heavy doses of oral steroids.

Ciliary staphyloma

• bulge of weak sclera lined by ciliary body.

• about 2-3 mm away from the limbus

• thinning of sclera following perforating injury,

• scleritis and absolute glaucoma.

Ciliary staphyloma

Equatorial staphyloma

• bulge of sclera lined by the choroid in the equatorial region

• at the regions of sclera which are perforated by vortex veins.

• causes= scleritis and degeneration of sclera in pathological myopia

Posterior staphyloma

• bulge of weak sclera lined by the choroid behind the.

• common causes are pathological myopia, posterior scleritis and perforating injuries.

• Diagnosis ophthalmoscopy.

• The area is excavated with retinal vessels dipping in it (just like

• marked cupping of optic disc in glaucoma)