DISEASES OF THE UVEAL TRACT – Definition, Types and Management
UVEITIS
Uveitis specifically refers to inflammation of the middle layer of the eye, termed the “uvea” (uval tract) but in common usage may refer to any inflammatory process involving the interior of the eye.
The uvea is made up of the iris (colored part of the eye), the ciliary body (ring of muscle behind the iris) and the choroid (layer of tissue that supports the retina). Inflammation of the uvea usually causes a red eye, sometimes with cloudy vision, and it may be painful. Uveitis may be caused by an injury, infection or underlying disease. If it is not treated, the eyesight can be seriously damaged.
ETIOLOGY AND RISK FACTORS
The cause of uveitis is often unknown, but it may result from:
- An injury to the eye (traumatic iritis), for example, a squash ball hitting the eye
- Recent or previous eye surgery
- Certain types of infection or
- A health condition such as an inflammatory or autoimmune condition (arthritis, rheumatoid arthritis, ankylosing spondylitis, sarcoidosis, psoriasis or inflammatory bowel disease), a bacterial, viral, fungal or parasitic infection (toxoplasmosis, gastroenteritis, tuberculosis, syphilis), and an immune-deficiency disease such as HIV/AIDS because this can make you prone to infection
TYPES OF UVEITIS
The type of uveitis depends on which part of the eye is affected:
1. Anterior uveitis: This is inflammation of the iris (iritis) or inflammation of the iris and the ciliary body (iridocyclitis). Only one eye is usually affected. It is the most common type of uveitis, accounting for 75% of cases.
Symptoms include: Eye pain, the pain can range from mild aching to intense discomfort, redness of eye, blurred or cloudy vision, a small pupil, an iris (the colored part of the eye) that may have a slightly different color, sensitivity to light (photophobia), floaters (dots that move across the field of vision) and headaches.
The symptoms may develop gradually over hours or days. They may be acute (lasting a few weeks) or chronic (lasting for more than three months).
2. Intermediate uveitis: Intermediate uveitis is the second most common type, affecting the area just behind the ciliary body and part of the retina. Both eyes tend to be affected and it is usually painless. It tends to occur in children, teenagers and young adults.
Symptoms include: Mild redness (although there is usually no redness), Floaters (dots that move across the field of vision), and Blurred vision due to cells from the blood vessels leaking into the gel of the eye. There is usually no redness or only mild redness associated with intermediate uveitis.
3. Posterior uveitis: Posterior uveitis affects the back of the eye (the choroid) where your blood vessels supply the retina. One or both eyes may be affected and it is usually painless. Posterior uveitis usually causes decreased vision and floaters, and sometimes retinal detachment. These symptoms are slower to develop and often last longer than those of anterior uveitis. Posterior uveitis can be more damaging to the eye than other types of uveitis. It sometimes causes visual loss.
Acute uveitis lasts for a few weeks and can recur, whereas chronic uveitis lasts for more than three months, with symptoms that can vary from day to day.
MANAGEMENT
The aim of treatment is to: control the inflammation, relieve any pain, treat any underlying condition, and treat any complications that may visual loss.
Treatment of uveitis will depend on the type of uveitis, how serious it is and the cause. Some cases will clear up with the use of eye drops. Others may need steroid injections into the eye.
- Mydriatic Eye Drops: such as atropine or cyclopentolate, dilates the pupil. This helps the eye to heal, prevents the pupil from getting stuck to the lens and decreases the eye pain. Mydriatic eye drops may cause blurred vision, difficulty focusing and an increased sensitivity to light, but they are a vital part of treatment.
- Steroid Eye Drops: steroid eye drops help decrease the inflammation of the iris. They will be used frequently at first and then tapered off, to prevent the uveitis recurring. Steroid eye drops are usually not used if a virus or bacteria caused the condition.
- Immunosuppressant: immunosuppressant is drugs that suppress the body’s immune system. Examples are cyclosporine, azathioprine and methotrexate
- Steroid tablets or steroid injections to the eye: steroid tablets (such as prednisolone) or a steroid injection into the eye may be recommended in severe cases of uveitis, when eye drops have no effect. The injection is done under local anaesthetic and you can go home on the same day.
DISEASES OF THE UVEAL TRACT – Definition, Types and Management