Inflammation of any part of the uveal tract, which is a group of connected structures inside the eye
- Age, gender, genetics, and lifestyle as risk factors depend on the cause
The uveal tract consists of several connected structures: the iris (the coloured part of the eye); the ciliary body (a ring of muscle behind the iris); and the choroid (a layer of tissue that supports the light-sensitive retina). Inflammation of any part of the uveal tract is called uveitis. The condition may involve the iris and/or the ciliary body (anterior uveitis or iritis) or the choroid (posterior uveitis). If uveitis is not treated, vision can be seriously impaired.
What are the causes?
Uveitis is most commonly caused by an autoimmune disorder, in which the body attacks its own tissues, such as juvenile chronic arthritis. There may be links with some inflammatory disorders, such as sarcoidosis, ankylosing spondylitis, Crohn’s disease, and ulcerative colitis. The condition may also occur with certain infectious diseases, including tuberculosis.
What are the symptoms?
Both anterior and posterior uveitis may affect only one eye. In anterior uveitis, the following symptoms may develop gradually over hours or days:
Redness and watering of the eye.
Sensitivity to bright light.
Aching in the eye.
Small, irregularly shaped pupil.
Symptoms of posterior uveitis develop rapidly and include:
Spots or haziness in the visual field.
Consult your doctor at once if your eye becomes red and painful and if you develop blurred vision.
The main danger in anterior uveitis is that the inflamed iris may stick to the lens. This prevents normal drainage of fluid through the pupil and increases the pressure inside the eye (see Acute glaucoma). If this rise in pressure is not treated promptly, it can lead to blindness. The condition may also increase the risk of developing a cataract. Repeated attacks can lead to permanent damage to the iris and deterioration in vision.
Occasionally, parts of the retina may be damaged irreversibly by posterior uveitis, resulting in partial or total loss of vision in the affected eye.
What might be done?
If uveitis is suspected, you may have a slit-lamp examination and ophthal moscopy, which examines the inside of your eye. If this is your first attack of uveitis, you will probably have other diagnostic tests to establish the underlying cause.
Your doctor may prescribe eyedrops to dilate the pupil and stop the iris from sticking to the lens, or corticosteroid eyedrops to reduce the inflammation (see Drugs acting on the eye). Treatment of uveitis is usually effective, but the condition tends to recur.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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