The immune system works to protect the body from foreign invaders, such as bacteria and viruses. Sometimes, however, the cells of the immune system fail to differentiate between invaders and normal, healthy cells. Autoimmune diseases are those diseases that occur when the immune system attacks the body. Autoimmune eye diseases include those diseases that primarily target the eye as well as diseases that target other parts of the body but also affect the eye.
Ocular Cicatricial Pemphigoid
Ocular cicatricial pemphigoid, OCP, describes a systemic autoimmune disease that belongs to a group of disorders known as mucus membrane pemphigoid, or MMP. MMP disorders cause damage to the mucus membranes lining the mouth, esophagus, trachea, nose, vagina and rectum, as described by the American Uveitis Society. Although the eye is the primary target for OCP, other systemic damage can occur, prompting a change in the preferred name to CP—cicatricial pemphigoid.
CP occurs when the white blood cells attack the conjunctiva—the mucus membrane that lines the outside of the eye. The disease usually begins in one eye causing irritation, burning and tearing of the conjuncitiva, a condition known as conjunctivitis. Over time the other eye will develop conjunctivitis as well. If left untreated, the condition progresses, causing scarring and shrinkage of the conjunctiva and the formation of adhesions. The eyes become excessively dry and lose the ability to move, with the scarring eventually causing blindness in both eyes.
Mooren's Corneal Ulcer
Doctors divide Mooren’s corneal ulcer, a rare autoimmune eye disease, into two types. Benign Mooren’s ulcer, limited type, is a disease that only affects one eye, producing mild to moderate symptoms, usually in older patients. Malignant Mooren’s ulcer often affects both eyes, causing pain and failing to respond to treatments.
In both types, the cells of the immune system attack the cornea, causing the formation of an ulcer, or open sore. Symptoms include redness of the eye, tearing of the cornea and photophobia—sensitivity to light, but patients complain of the pain the most. As the ulcer develops, it spreads to involve the entire cornea. Mooren’s corneal ulcer leads to corneal perforation, a tear in the cornea, in 35 to 40 percent of cases, according to the Ocular Immunology and Uveitis Foundation.
Uveitis
Uveitis describes a condition involving inflammation of the uvea—the layer of the eye between the retina and the white of the eye, known as the sclera. The uvea consists of the iris, the choroid layer and the ciliary body. Uveitis can occur due to an eye injury but usually occurs in association with an autoimmune disorder.
Autoimmune disorders such as rheumatoid arthritis, which affects 1.3 million Americans, according to the Arthritis Foundation, ankylosing spondylitis and Crohn’s disease cause inflammation in the body that can affect the uvea. Symptoms of uveitis include redness, pain, sensitivity to light and blurred vision. Doctors at Mayoclinic.com report that inflammation of the iris, a condition known as anterior uveitis, is the most common form of uveitis. Uveitis can lead to permanent vision loss.
