Scleritis

Dr Ben Wild

Overview

The sclera is the white layer of the eye. Its function is as a strong barrier that holds the contents of the eye. It extends from the cornea to the optic nerve at the back.

Frontal view of a healthy eye.

Scleritis refers to inflammation and swelling of the sclera. It is commonly categorized into anterior non-necrotizing, anterior necrotizing, and posterior scleritis. Symptoms range from mild to severe.

Anterior non-necrotizing is the most common and appears either as spread out (diffuse) or as nodular (large bump). Diffuse commonly associates with autoimmune conditions and progresses with symptoms worsening over days. It tends to reoccur on average every 6 years. Nodular is more commonly caused by infectious agents. It progresses slower and can last up to 6 years.

Anterior necrotizing scleritis is the most aggressive. It typically affects older individuals, is caused by severe infections or end stage autoimmune diseases, results in extreme pain, and profound vision loss.

Posterior scleritis can be seen alongside anterior scleritis or on its own. It is usually found with other retrobulbar inflammatory conditions (conditions that affect the back of the eye) such as optic neuritis, inflammation of the eye muscles (myositis), and more. Ultrasound may be needed for diagnosis.

Frontal view of an eye with necrotizing scleritis on the left of the picture and diffuse scleritis on the right.

Signs and Symptoms

Signs

Anterior non-necrotizing	Diffuse redness or intense redness around a hard blue or red nodule, swelling of the eye, eyelid swelling, uveitis (inflammation inside the eye), elevated eye pressure.
Anterior necrotizing	Same as above but more severe, ulceration/thinning/perforation of the sclera.
Posterior	Swollen but no visible redness, retinal detachment, choroidal detachment and/or folds, optic nerve swelling/neuritis, myositis, bulging outward of the eye (proptosis).

Symptoms

Anterior non-necrotizing	Fast or slow progression of pain radiating to face, mild to severe light sensitivity, mild blurry vision.
Anterior necrotizing	Same as above but more severe.
Posterior	Same as anterior non-necrotizing, pain on eye movement, potential for extreme loss of vision, although light sensitivity is uncommon.

Causes and Risk Factors

Causes

Inflammation of the sclera.

Risk Factors

Infectious (herpes zoster virus, tuberculosis, Leprosy, syphilis, Lyme, fungus and more), autoimmune disease (rheumatoid arthritis, Wegner’s granulomatosis, polyarteritis nodosa, polychondritis, sarcoidosis, ankylosing spondylitis, etc.).

Prevention and Treatment

Prevention

Treat infections timely and use prophylactic immune modulating medications when there is an auto-immune condition.

Treatments

· Determine cause via blood work, chest x-ray, sinus/joint imaging, orbital CT scans, ultrasound imaging or biopsy for infection.

· Artificial tears for very mild.

· Steroid eye drops for mild.

· Non-steroidal anti-inflammatory pills for mild.

· Steroid injection for moderate.

· Steroid pills for severe.

· Disease modifying anti-rheumatic drugs for severe.

Prognosis

Anterior non-necrotizing scleritis is usually recurrent and leads to thinning of the sclera, turning the sclera blue, and permanently dilated blood vessels but does not cause any further morbidity or affect vision. Necrotizing scleritis can be vision threatening and is even associated with a 5-year mortality rate of 50-60% if caused by an auto-immune disorder. If not treated promptly, it can lead to the loss of the eye or death. Posterior scleritis can lead to retinal detachments, choroidal detachments, optic neuritis or swelling and other conditions that cause permanent vision loss even if treated promptly.