Scleritis 

Scleritis is a chronic, painful, and potentially blinding inflammatory disease that is characterized by edema and cellular infiltration of the scleral and episcleral tissues. Scleritis is commonly associated with systemic autoimmune disorders, including rheumatoid arthritis, systemic lupus erythematosus, relapsing polychondritis, spondyloarthropathies, Wegener granulomatosis, polyarteritis nodosa, and giant cell arteritis.

Scleritis may be the initial or only presenting clinical manifestation of these potentially lethal disorders. The correct and rapid diagnosis and the appropriate systemic therapy can halt the relentless progression of both ocular and systemic processes, thus preventing destruction of the globe and prolonging survival.

Scleritis may be classified into anterior and posterior. Anterior scleritis can be diffuse, nodular, necrotizing with inflammation (necrotizing), and necrotizing without inflammation (scleromalacia perforans). The most common clinical forms are diffuse scleritis and nodular scleritis. Necrotizing scleritis with or without inflammation is much less frequent, more ominous, and frequently associated with systemic autoimmune disorders. Posterior scleritis is characterized by flattening of the posterior aspect of the globe, thickening of the posterior coats of the eye (choroid and sclera), and retrobulbar edema.

An autoimmune dysregulation in a genetically predisposed host is presumed to cause scleritis. Inciting factors may include infectious organisms, endogenous substances, or trauma. The inflammatory process may be caused by immune complex–related vascular damage (type III hypersensitivity) and subsequent chronic granulomatous response (type IV hypersensitivity).

The following interact as part of the activated immune network, which can lead to scleral destruction: immune complex vessel deposition in episcleral- and scleral-perforating capillary and postcapillary venules (inflammatory microangiopathy) and cell-mediated immune responses. The autoimmune nature of scleritis also is supported by the frequent association with systemic autoimmune disorders and by the favorable response to immunosuppressive therapy.

Frequency

United States

The exact incidence of scleritis is uncertain, although scleritis is not common. The reported prevalence of scleritis is skewed by the somewhat selected referrals of the reporting institutions. Approximately 2.6% of patients who were referred to the Immunology Service at the Massachusetts Eye and Ear Infirmary Hospital of Boston during an 11-year period had scleritis.

International

Approximately 0.08% of patients who were referred to the Department of Ophthalmology of Southern General Hospital and Victoria Infirmary of Glasgow during an 8-year period had scleritis.

Mortality/Morbidity

Patients with scleritis are at risk for ocular complications and systemic disease association.

• Ocular complications of scleritis, which cause vision loss and eye destruction, appear as a result of the extending scleral inflammation. Peripheral ulcerative keratitis (13-14%), uveitis (about 42%), glaucoma (12-13%), cataract (6-17%), and fundus abnormalities (about 6.4%). These complications are most common in necrotizing scleritis, the most destructive type of scleritis.
• Disease association may be found in about 57% of patients with scleritis. Up to 48% of patients with scleritis present with a known connective-tissue or vasculitic disease. Some of these diseases are potentially lethal unless treated with prompt and aggressive therapy. Other patients may present with concomitant trauma, infection, or postsurgical inflammation. Systemic disease association is most common in cases of necrotizing scleritis. Scleritis may be the first manifestation of a potentially lethal systemic disease.

Sex

Women are more likely to have scleritis than men (1.6:1).

Age

Scleritis is most common in the fourth to sixth decades of life. The peak incidence of scleritis is in the fifth decade.