Uveitis

Most patients are  aware of eye conditions such as cataract and glaucoma but I notice when they are informed of a diagnosis such as uveitis they are thrown into the dark on what this actually is all about.

Uveitis is inflammation or swelling of the uvea, which is  middle layer of the eyeball. In the front of the eye it forms the iris and  pupil. . The iris is the colored ring of tissue you can see when you look in the mirror. The dark hole in the middle of the iris is the pupil. The other parts located behind the iris are the ciliary body and the choroid.  Uveitis can occur in any parts of these structures solely or in combination.

Inflammation of the front of the eye or iris is called anterior uveitis.  Inflammation of the ciliary body is called intermediate uveitis . Inflammation of the choroid is called choroiditis. Inflammation of all three parts is called panuveitis.

What are the symptoms of uveitis?

There are no specific symptoms as a lot of ocular problems share similar symptoms however a pink eye( mild redness) with sensitivity to light associated with blurry vision are some of the common symptoms of uveitis. If the uveitis occurs in the back of the eye, floaters may be present as well.

What causes uveitis?

Uveitis usually is due to an autoimmune disorder. This means that the  body’s immune cells or “soldiers” decide to attack the eye.It may be associated with other systemic autoimmune diseases such as sarcoidosis, rheumatoid arthritis, SLE, Behcet disease, inflammatory bowel disease and ankylosing spondilitis.  I usually will have to go through a detailed history to obtain symptoms of such conditions. Infections such as toxoplasmosis ( a parasite found in cats), syphllis  and tuberculosis too may occur in the eye and present with uveitis.  Interestingly in many of my patients it was the uveitis that clinched the diagnosis of a larger problem . The eye indeed is the window to the body.   However in many cases (up to 50%) there is no definite cause for the uveitis.

How do we diagnose uveitis?

Uveitis is diagnosed by a combination of symptoms obtained form the history, examination findings as well as laboratory investigations. All patient with suspected uveitis  need to be examined with a slit lamp microscope. Your eye doctor will look for features of uveitis such as white blood cells in the front and back of the eye. In uveitis there is  invasion of white blood cells (immune cells of inflammation found in the bloodstream) into the uvea . These white cells permeate the uveal tissue and also leak out of the uvea into other parts of the eye. There also may be an irregularity in the shape of the pupil as the iris when inflamed can stick to the adjacent lens altering the shape of the pupil. Your eyes will have to be dilated to look for features of  uveitis in the back of the eye and a special microscope mounted on the head may be used to examine the peripheral retina. In cases of uveitis in the back of the eye( intermediate uveitis) there may be swelling of the centre of the retina called macula edema. This swelling is confirmed on a  scan called the OCT.All these examination procedures are painless and involve using a light source to examine the eye.