What is uveitis?
The immune system protects us from disease and is amazingly complex. Like other complex systems in our body, the immune system can malfunction. When the immune system malfunctions and acts on our own body’s tissues, that is autoimmune disease (“auto-” for “self”).
Autoimmune disease can affect any part of the body. The most well known is rheumatoid arthritis of the joints, for which people may see a rheumatologist or orthopedic doctor. Autoimmune diseases can also affect the brain, ears, liver, kidneys, lungs, heart, stomach and intestines, muscles, and peripheral nerves. Essentially any part of the body, including the eye, can be affected by autoimmune disease. Autoimmune disease of the eye is known as uveitis. Immune cells enter the eye, become active, and exert their effects (“inflammation”). The normal eye does not have significant inflammation at any one time. For the sake of classification, we classify uveitis as:--anterior if it affects the front part of the eye.--intermediate if it affects the middle or vitreous gel portion of the eye.--posterior if it affects the retina and/or choroid.--”pan” as in “panuveitis” if all three compartments of the eye are affected.
Uveitis can reduce vision in may ways. Going from “front to back,” the cornea, the very front window into the eye, may develop calcium deposits that block vision. The lens of the eye may develop clouding, known as cataract. The front colored portion of the eye, the iris, may develop adhesions. The vitreous gel of the eye may develop cloudiness (“haze”) and floaters. The center of the retina, the macula, may develop swelling (macular edema). If the RPE-choroid underneath the retina thins or atrophies with chronic inflammation the retina itself will lose visual function. The cells in the retina can degenerate with chronic inflammation.
How is uveitis treated?
Uveitis is treated with medicines that damp down the activity of the immune system. Steroids are are first line of treatment. Steroid eye drops may treat uveitis in the front portion of the eye. For intermediate or posterior uveitis affecting the vitreous gel or retina and choroid, steroid eye drops alone are insufficient. We recommend steroids taken by mouth and/or injections of steroids underneath the skin layer of the eye (“subTenons” injection). Steroids are generally used for one to three months to quiet the inflammation and the dosage is then tapered. Steroids are not continued indefinitely as long term steroid use has significant side effects, both on the eye itself and on the rest of the body (when the steroids are taken by mouth).
In some patients, uveitis treated in this fashion will “stay quiet” for months to years after the steroids are stopped. In other patients with more severe disease, the inflammation will return quickly. In these patients, therapy may be needed for months to years. In this case, we recommend alternative non-steroid medications that can be taken for longer time periods without the side effects of steroids. These medications are borrowed from the field of organ transplantation and include methotrexate, azathioprine (Imuran), mycophenolate (Cellcept), cyclosporine, infliximab (Remicade), daclizumab (Zenapax), and others. These medicines do have their own possible side effects and a patient on these medications needs to be monitored in conjunction with an internal medicine doctor while on the medications. In general, however, when we recommend these medications, we believe the potential benefit of the medicines in preserving vision justifies the risk of side effects of the medicines.