Scleritis

Scleritis vs episcleritis

The episclera is a thin layer of tissue lying over the sclera. Episcleritis is much more common and benign.

Types of scleritis

• Diffuse anterior scleritis: the most common; widespread redness and swelling.
• Nodular anterior scleritis: a firm, tender, immobile nodule.
• Necrotizing scleritis with inflammation: severe pain and tissue destruction; strongly linked to systemic vasculitis and rheumatoid arthritis.
• Scleromalacia perforans: necrotizing scleritis without inflammation, with painless thinning, usually in long-standing rheumatoid arthritis.
• Posterior scleritis: affects the back of the eye; may cause pain, blurred vision, double vision and bulging, with little visible redness.

Causes

Autoimmune and systemic diseases (about 50%)

• rheumatoid arthritis (the most common)
• granulomatosis with polyangiitis and other ANCA-associated vasculitis
• lupus
• relapsing polychondritis
• inflammatory bowel disease
• ankylosing spondylitis, psoriatic arthritis, sarcoidosis

Scleritis may be the first sign of an undiagnosed systemic disease.

Infections (about 5 to 10%)

• herpes zoster (shingles) and herpes simplex
• bacterial or fungal infection, especially after eye surgery or injury
• tuberculosis, syphilis, Lyme disease

Other

• after eye surgery (surgically induced necrotizing scleritis)
• some medicines, such as bisphosphonates
• idiopathic (no cause found)

Symptoms

• severe, deep eye pain, often radiating to the brow, temple or jaw, worse at night and with eye movement
• redness, often with a bluish or violet tinge
• tenderness of the eye to touch
• tearing and light sensitivity
• blurred vision
• in posterior scleritis: pain, reduced vision, double vision, bulging with little redness

Diagnosis

• Slit lamp exam in daylight and with phenylephrine drops to distinguish from episcleritis
• dilated eye exam for posterior involvement
• B-scan ultrasound for posterior scleritis (a characteristic "T sign")
• OCT or MRI in some cases
• blood tests to look for systemic disease: rheumatoid factor, anti-CCP, ANCA, ANA, inflammatory markers, syphilis and tuberculosis testing, kidney function and urine tests

Treatment

• Oral NSAIDs: for mild diffuse or nodular scleritis.
• Oral corticosteroids: for more severe disease or when NSAIDs fail.
• Immunosuppressive medicines: methotrexate, mycophenolate, azathioprine or cyclophosphamide.
• Biologics: rituximab (especially for GPA-related scleritis) and TNF inhibitors such as infliximab or adalimumab.
• Antimicrobials for infectious scleritis.
• Treating the underlying disease with a rheumatologist.
• Surgery: scleral patch grafts for severe thinning or perforation.

Steroid injections near the eye are generally avoided in necrotizing scleritis.

Complications

• uveitis and keratitis
• cataract and glaucoma
• scleral thinning and perforation
• retinal detachment and optic nerve swelling (posterior scleritis)
• permanent vision loss

Necrotizing scleritis associated with systemic vasculitis also signals a higher risk of serious disease elsewhere in the body.

Frequently asked questions

What are the symptoms of scleritis?

The main symptom is severe, deep eye pain that may spread to the face and worsen at night or with eye movement. The eye is red, often with a purplish tinge, and tender. Light sensitivity, tearing and blurred vision may occur.

What causes scleritis?

About half of cases are linked to autoimmune or inflammatory diseases, especially rheumatoid arthritis and granulomatosis with polyangiitis. Infections such as shingles, eye surgery and some medicines are other causes. Sometimes no cause is found.

How is scleritis different from episcleritis?

Episcleritis affects the thin layer over the sclera, causes mild discomfort and usually resolves on its own. Scleritis affects the deeper sclera, causes severe pain, can damage vision and needs systemic treatment.

Is scleritis serious?

Yes, it can be. Scleritis can lead to vision loss, thinning or perforation of the eye wall, and may indicate a serious underlying disease. Prompt treatment by an eye specialist, often working with a rheumatologist, is important.

How is scleritis treated?

Treatment depends on severity: oral NSAIDs for mild cases, and oral steroids, immunosuppressants or biologic medicines for more severe or necrotizing disease. Infections are treated with antimicrobials, and any underlying disease is treated as well.