Diseases of Sclera

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Special features of Sclera
•    Avascular
•    Dense fibrous tissue
•    Lack of reaction to insult
•    Two types of inflammation - episcleritis and scleritis



Episcleritis
•    Benign inflammatory affection of deep subconjunctival connective tissue and superficial scleral lamellae
•    Mostly bilateral
•    Dense lymphocytic infiltration
•    Reaction to endogenous toxin
•    Association with rhuematoid arthritis

Symptoms and Signs
•    Young females
•    Acute redness
•    Mild pain
•    No discharge
•    Two types     - simple or diffuse
                        - nodular


Simple /diffuse episcleritis
•    Sectorial or diffuse redness
•    One or both eyes
•    Mild to moderate tenderness over the area of redness
•    Engorgement of large episcleral vessels which run in radial direction beneath the conjunctiva

Nodular Episcleritis


Treatment
•    Mild to moderate- weak topical steroids
•    Fluorometholone eye drops  4 times a day and lubricating drops
•    Severe form - stronger steroids as prednisolone acetate eye drops 4-6 times a day
•    Non steroidal anti inflammatory drugs like-ibuprofen 400 mg thrice daily or indomethacin can be given

Scleritis
•    Extends more deeply
•    Deep lymphocytic infiltration deep with in the scleral tissue
•    Bilateral, rarer, more in females
•   
•    Associated with connective tissue disorder in 50% cases  like - polyarteritis nodosa, SLE, reiters syndrome  ankylosing spondylitis, wegners grannulomatosis, dermatomyositis, polychondritis, gout, herpes zoster ophthalmicus,syphilis
•    Recent ocular surgery as cataract or RD surgery


A. Anterior scleritis
–    Nodular
–    Diffuse
–    Necrotising     - with inflammation                                - without inflammation
B.  Posterior scleritis



Nodular scleritis
•    One or more nodules
•    Less circumscribed than episcleritis
•    First dark red or bluish later becomes purple and semitransparent like porcelain
•    All around cornea-annular scleritis –grave prognosis


Diffuse scleritis
•    Hard whitish nodule pin head size with inflamed surrounding zone
•    Disappear without disintegration



Clinical features of Scleritis
•    Cornea and uveal tract are always involved as contrast to episcleritis
•    Some iritis  more often cyclitis and ant. Choroiditis
•    No ulceration
•    Dark purple weak cicatrix-ciliary staphyloma
•    Secondary glaucoma common


Sclerosing keratitis
•    Extends to cornea
•    Opacity develops at the margin of cornea adjoining scleritis
•    Tongue shaped, rounded apex towards center of cornea
•    No corneal vascularisation or ulceration
•    Pupillary area is usually spared
•    Keratolysis is a serious complication


Necrotizing scleritis
•    Scleral necrosis
•    Severe thinning
•    Melting of sclera
•    Two types    - with inflammation
                       - without inflammation


Necrotizing scleritis with inflammation
•    Red ,painful eye, worsening of symptoms
•    Associated with ant uveitis
•    Autoimmune disorder
•    Complications-glaucom, cataract, sclerosing keratitis, scleral melting are common
•    Five year survival of patients at this stage of autoimmune disorder is 25%


Necrotizing scleritis without  inflammation-
scleromalacia perforans
•    Patients with seropositive rheumatoid arthritis
•    Painless scleral thinning and melting
•    Cause is ischemia


Posterior scleritis
•    Inflammation with thickening of posterior sclera
•    Primary or secondary extension of anterior scleritis
•    Not associated with systemic disease
•    Usually no symptoms


Symptoms and Signs
•    Decreased vision
•    With or without pain
•    Proptosis
•    Restricted ocular movements
•    Post vitritis, disc edema ,macular edema, choroidal detachment exudative retinal detachment
•    B-scan and CT scan shows thickened sclera



Diagnosis – episcleritis / scleritis
•    Full blood count
•    RA factor
•    Mantoux test
•    ANA
•    Anti neutrophill cytoplasmic antibody

•    VDRL
•    Serum uric acid
•    X-ray chest, sacro iliac joint
•    LE cells
•    Full immunological survey for tissue antibodies


Treatment
•    Diffuse and nodular scleritis- NSAID
•    Prednisolone -1mg /kg single morning dose
    Tapered to 20 mg over 2-3 weeks
•    H2 receptor blockers
•    Necrotizing scleritis - additional immunosuppressant are recommended
•    Abundant lubricant
•    Scleral patch graft may be needed if risk of perforation

Posterior scleritis
•    Same as ant scleritis
•    IV Methylprednisolone as pulse therapy
•    Local steroids ineffective
•    SUBCONJUNCTIVAL INJECTIONS CONTRAINDICATED
•    Infectious diseases are treated with appropriate antibiotics

Staphyloma
•    Staphyloma is a clinical condition characterised by an ectasia of the outer coats (cornea,or sclera or both) with an incarceration of uveal tissue
•    Two factors work - weakening of the outer wall and raised IOP

TYPES
•    Anterior
•    Intercalary
•    Ciliary
•    Equatorial
•    Posterior


Anterior staphyloma
•    Partial or total
•    Mostly after sloughed cornea and pseudocornea formation
•    AC becomes flat with secondary glaucoma
•    Iris is incarcerated in anterior staphyloma

Intercalary staphyloma
•    Limbus
•    Root of iris and anterior most part of ciliary body
•    Externally from limbus to 2mm behind
•    Caused by - perforating injury at peripheral cornea involving limbus, marginal corneal ulcers, anterior scleritis, scleromalacia perforans, complicated cataract surgery with wound dehisence, secondary glaucoma


Ciliary staphyloma
•    Affects ciliary zone - upto 8 mm behind the limbus
•    Scleral ectasia with incarceration of ciliary body
•    Caused by - developmental glaucoma, end stage of primary or sec glaucoma, scleritis, trauma to ciliary region of eye


Equatorial staphyloma
•    Equatorial region of eye with incarceration of choriod
•    14 mm behind the limbus weak area due to passage of venae vorticosae
•    Caused by scleritis , chronic uncontrolled glaucoma, degenerative myopia


Posterior staphyloma
•    Posterior pole of eye lined by choroid
•    Degenerative high myopia
•    Detected by fundoscopy and B- scan ultrasonography



Treatment
•    Treat the cause
•    Small –local excision with corneo-scleral graft
•    Large unsightly blind eyes are enucleated and replaced with implant


Dr Kavita Kumar
Associate Professor
Department of Ophthalmology
Gandhi Medical College
Bhopal