Scleritis

Scleritis refers to inflammation of the sclera. It has a wide range of causes.

Epidemiology

It can affect any age group but usually those between ages 30 and 50 years. There is a recognized increased female predilection (F:M of ~2:1).

Associations

Scleritis can be associated with systemic infections as well as non-infective systemic conditions which include ¹:

• rheumatoid arthritis: 18-33%

• systemic vasculitides: 7-19%

  • granulomatosis with polyangiitis: most common

• systemic lupus erythematosus: 4-7%

• inflammatory bowel disease: 4-7%

• relapsing polychondritis: 3%

• Behçet disease: rare ⁶

• sarcoidosis: rare

• cryoglobulinaemia: rare

• hypocomplementaemic urticarial vasculitis: rare

• Cogan syndrome

• herpes zoster infection: most commonly associated infection

Pathology

Information on the pathogenesis of scleritis is limited due to a lack of published data. However, a predominant role for T cells in the inflammatory process has been postulated ¹.

Classification

One widely used classification system is the Watson and Hayreh system which divides scleritis into anterior and posterior forms based upon the anatomic distribution.

• anterior scleritis (defined by the point of rectus muscle insertion)

  • diffuse anterior scleritis

  • nodular anterior scleritis

  • necrotizing anterior scleritis with inflammation

  • scleromalacia perforans (necrotizing anterior scleritis without inflammation)

• posterior scleritis

Radiographic features

Ultrasound

Ocular ultrasound may play a role in the diagnosis and management of posterior scleritis, demonstrating scleral thickening.

CT/MRI

CT and MRI imaging may also play a role in the diagnosis of scleritis especially during the active phase of the disease. Radiological findings include:⁷

• scleral thickening

• scleral enhancement

• focal periscleral cellulitis

See also

• orbital pathology