What Is Uveitis? What Causes Uveitis? What Is Iritis?

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Main Category: Eye Health / Blindness
Article Date: 06 Oct 2009 - 9:00 PDT

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Uveitis is the inflammation of the uvea (or uceal tract), which is the middle layer of the eye. The uvea extends toward the front of the eye and consists of the iris (colored part of the eye), choroid layer (layer of tissue that supports the retina) and the ciliary body (ring of muscle behind the iris). Iritis - inflammation of the iris - is the most common type of uveitis.

Inflammation of the uvea may be painful. It usually causes a red eye, sometimes with cloudy vision.

Uveitis may be caused by an injury, infection or an underlying disease. It is most frequent in people aged 20 to 50 years. If not treated the person's eyesight can be seriously damaged. To prevent complications, early diagnosis and treatment are essential.

According the Medilexicon's medical dictionary, uveitis is "Inflammation of the uveal tract: iris, ciliary body, and choroid."

What are the symptoms of uveitis?

A symptom is something the patient feels or reports, while a sign is something other people, including a doctor, may detect. For example, a pain may be a symptom while a rash may be a sign.

The signs, symptoms and characteristics of uveitis can be noticeable in one or both eyes. They include:

• Blurred or cloudy vision
• Dark, floating spots or dots in your field of vision (floaters)
• Decreased vision
• Eye pain that can range from mild aching to intense discomfort
• Eye redness
• Light sensitivity (photophobia)
• Headaches
• A small pupil
• The iris (the colored part of the eye) may have a slightly different color

There can be sudden or gradual appearance of the symptoms. In some cases they worsen rapidly in hours.

There are three different types of uveitis:

• Anterior uveitis - it affects the front of the eye (usually the iris) and is the most common type.


• Intermediate uveitis - it is the second most common type, affecting the area just behind the ciliary body and part of the retina. It is usually painless.


• Posterior uveitis - it affects the back of the eye (the choroid). One or both eyes may be affected and it is usually painless. These symptoms are slower to develop and often last longer. It can be more damaging to the eye than other types of uveitis and may sometimes cause visual loss.

What are the causes of uveitis?

Often, the cause of uveitis cannot be determined. However, in some people, uveitis is linked to:

• Eye injury (such as a trauma from something hitting the eye…).


• Recent or previous eye surgery.


• A bacterial, viral, fungal or parasitic infection such as syphilis, toxoplasmosis, tuberculosis, gastroenteritis, Lyme disease, syphilis or shingles.


• An immune-deficiency disease. When the body's immune system is impaired it is more susceptible to infection, such as HIV/AIDS.


• Autoimmune disorders. When the body attacks its own organs, (such as rheumatoid arthritis or ankylosing, spondylitis, Reiter's syndrome, Behçet's disease, sarcoidosis, psoriasis or inflammatory bowel disease…).


• Certain cancers, such as lymphoma, that have an indirect effect on the eye.


• Inflammatory disorders, such as Crohn's disease or ulcerative colitis.

Diagnosis of uveitis

A visit to the ophthalmologist will include questions about the signs, symptoms and general health history.

If there is suspicion that an underlying condition could be the cause of uveitis, there could be a referral to another doctor for a general medical examination and special laboratory tests. It is essential to determine whether the uveitis has an infectious cause or results from another disease or condition.

During the examination the eye is examined with a special slit lamp. In the case of uveitis, white blood cells and protein in the eye fluid can be seen through the microscope. As the light beam passes through the eye, the fluid inside is appears to be hazy instead of clear. Light will cause a slight pain in the eye as the pupil constricts if it is affected by uveitis.

Blood tests, X-rays and other tests may be done to determine the cause of the uveitis.

It is important to distinguish uveitis from conjunctivitis which only affects the outside of the eye and does not affect vision.

What is the treatment for uveitis?

Treatment depends on the severity of uveitis and its cause. The objective is to control the inflammation, relieve any pain, treat an underlying condition if there is one, and any complications that may cause visual loss. It may include:

• Antibiotic or antiviral medication. If uveitis is caused by an infection, antibiotics, antiviral medications or some other medicine may be given with or without corticosteroids to control the infection.


• Anti-inflammatory medication. Such as a corticosteroid. This medication may be given as eye drops, pills or by injection into the eye. Steroid eye drops help decrease the inflammation of the iris. They will be used frequently in the beginning and retrieved gradually to prevent the uveitis from recurring. Steroid eye drops are usually not used if a virus or bacteria caused the condition. When eye drops have no effect, steroid tablets (such as prednisolone) or a steroid injection into the eye may be recommended in severe cases of uveitis. The injection is done under local anesthetic and the patient can go home on the same day.
  
  In some cases, a steroid drip (methylprednisolone) may be given in hospital.
  
  If the condition is diagnosed early and treated with eye drops, no visual loss should occur.


• Immunosuppressive or cytotoxic medication. Immunosuppressive or cytotoxic agents may be considered necessary if there is poor response to corticosteroids or if vision is threatened. Immunosuppressants are drugs that suppress the body's immune system (ciclosporin, azathioprine, and methotrexate).


• Mydriatic eye drops, such as atropine or cyclopentolate. They dilate the pupil and help the eye to heal. This prevents the pupil from sticking to the lens and also decreases eye pain. Mydriatic eye drops are an essential part of treatment but they may cause blurred vision, difficulty focusing and an increased sensitivity to light. Prolonged steroid treatment needs to be carefully monitored for side effects.


• Surgery. Vitrectomy is surgery to remove the gelatinous material in the eye. It may sometimes be necessary for diagnosis and treatment of uveitis.

How long uveitis lasts depends on which part of the eye is affected (anterior or posterior of the uvea). With proper treatment, anterior uveitis can clear up in a matter of days to weeks. On the other hand, posterior uveitis may last several months or years. In some cases, vision can be permanently altered.

In the case of recurrent uveitis it is important to get it treated quickly. Seek medical assistance if any of symptoms reappear after successful treatment.

What are the complications of uveitis?

It is important to closely monitor this condition. Complications may develop and lead to loss of vision:

• Abnormal high eye pressure and glaucoma - Untreated uveitis can cause the iris to stick to the front surface of the lens. This prevents fluid from draining through the pupil. As a result it increases pressure inside the eye. It can lead to visual loss, glaucoma and damage to the optic nerve.
  
  Since raised eye pressure can be a side effect of steroid eye drops, it is important to use them in the lowest possible dose.


• Cataracts - Untreated uveitis can cause cataracts. It is a cloudiness of the lens or cornea that can lead to visual loss.


• Macular edema - Macular edema is fluid that collects in a part of the retina called the macula. It can lead to retinal detachment and can result from untreated posterior uveitis. It may lead to loss of vision.


• Scar tissue inside the eye may also result from uveitis.

With adequate care, Uveitis should improve within two to three weeks of treatment. Traumatic uveitis resulting from an injury to the eye usually goes away within a week.

The sooner treatment is started, the quicker the recovery.

Useful tips

If there is sensitivity to light, wear dark glasses.
The use of gentle and warm compresses over the eye may help to soothe it.
Also, aspirin or Ibuprofen can be taken to relieve pain.

Written by Stephanie Brunner M.A.
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today