scleritis

Scleritis is an inflammatory disease of the sclera, the white outer layer of the eye. It is less common than episcleritis and typically causes deep, painful eye involvement that can threaten vision. Scleritis can be anterior, involving the visible sclera, or posterior, affecting the back of the eye; necrotizing forms are particularly severe.

Patients usually experience a deep, boring eye pain that worsens with eye movement, along with redness, tearing, and sensitivity to light. Anterior scleritis often shows a violaceous, segmental injection and scleral tenderness, with possible scleral thinning or nodules over time. Posterior scleritis may present with vision changes, proptosis, or diplopia and can be harder to detect on external examination; imaging is often required to assess the extent.

Most cases are idiopathic or linked to systemic autoimmune diseases such as rheumatoid arthritis, granulomatosis with polyangiitis, lupus, or inflammatory bowel disease. Infections can rarely cause scleritis, so distinguishing infectious from noninfectious forms is important because treatments differ.

Diagnosis relies on clinical examination and imaging. Slit-lamp biomicroscopy assesses scleral inflammation, while ultrasound-based techniques help identify posterior involvement. MRI or CT can delineate extent. Laboratory tests screen for systemic disease; biopsy is reserved for suspected infectious or necrotizing cases or when the diagnosis remains unclear.

Treatment depends on type and cause. Noninfectious anterior scleritis is treated with nonsteroidal anti-inflammatory drugs or systemic corticosteroids; refractory cases may require immunosuppressants such as methotrexate, azathioprine, mycophenolate, or cyclophosphamide. Posterior scleritis usually requires systemic therapy. Infectious scleritis requires targeted antimicrobials and sometimes surgical intervention. Corticosteroids should be used cautiously after infection has been excluded.

Outcomes vary with form and promptness of treatment. Many patients improve, but necrotizing or posterior disease carries a higher risk of vision loss and scleral thinning, and relapses are common.