People with arthritis know to expect painful, swollen and tender joints. What they may not expect is the effect arthritis can have on a completely different part of the body - the eyes.

Many forms of arthritis and related diseases have an effect on the eyes. Eye problems can result from inflammation associated with arthritis or the medications used to treat it. In some cases, eye problems can indicate potentially dangerous conditions elsewhere in the body.

Here are detailed descriptions about some of the more common arthritis-related eye problems, including symptoms to watch out for. We've broken these conditions down by the form of arthritis or condition with which they're associated.

Giant Cell Arteritis (GCA), which is an inflammation of the blood vessels that supply the head, occurs in about half of people with PMR. This inflammation can sometimes block the flow of blood to the optic nerve and cause vision problems, such as blurring, double-vision and - in 10 to 15 percent of people with GCA - even blindness.

Iritis, inflammation of the iris or colored part of the eye, affects approximately 20 to 30 percent of people with AS. The inflammation comes on suddenly, usually in one eye at a time, causing the affected eye to become red and painful. Individual incidents may last for a couple of months or more and recur a few times a year or over a period of years.

Scleritis, a chronic inflammation of the blood vessels in the whites of the eyes, occurs in about 1 percent of people with RA. Symptoms include eye pain and redness. If it goes untreated, scleritis may become severe, leading to a deterioration of the cornea.

People with RA are also at increased risk for Sjögren's syndrome, classified in this case, as secondary Sjögren's syndrome. (see below)

Dry Eyes are a key symptom of Sjögren's syndrome, a chronic condition that occurs when the body's immune system mistakenly attacks moisture-producing glands, including the tear glands. Symptoms include a burning, gritty feeling. If not alleviated, dryness can lead to eye infections or even damage to the cornea.

Cotton Wool Spots - white, puffy patches that appear on the retina and can be seen during an eye exam - occur in about 7 percent of people with lupus. The spots are caused by compromised blood supply to the retina. When this occurs, blood supply to other organs may be insufficient as well, resulting in problems as severe as a stroke. Fortunately, detecting the spots can tip doctors off to other problems, ensuring prompt or even preventive treatment. The spots themselves do not affect vision.

Iritis also occurs in about half of children with pauciarticular JRA, which begins in childhood and generally affects four or fewer joints. JRA-related iritis is often asymptomatic and is known to continue into adulthood.

Because detecting and treating eye problems early can, in many cases, prevent long-term complications, you may need to schedule regular appointments with an ophthalmologist (a medical doctor who specializes in diseases of the eye) as well. Experts recommend that people who are taking antimalarial drugs such as hydroxychloroquine (Plaquenil) make it a priority to have their eyes checked by an ophthalmologist every year, although in some cases less frequent visits may be sufficient. Ask your doctor to help determine the frequency of eye check-ups that's best for you.

In addition to the eye problems arthritis-associated inflammation can cause, some medications used to treat arthritis-related disease can create trouble of their own. Most notable are antimalarial drugs such as hydroxychloroquine and glucocorticoids such as prednisone.

Hydroxychloroquine, used to treat and slow the progression of such diseases as RA and lupus, can in rare cases damage the retina and cause blindness. Such damage can be prevented by taking low doses of the drug and by seeing an ophthalmologist regularly to detect damage before it becomes severe. Stopping the drug may reverse early harm.

Prednisone, one of the most widely used inflammation-fighting drugs, can increase risk of cataracts and glaucoma. Cataracts are a cloudiness of the eye's lens resulting in blurred vision. In glaucoma, excessive fluid buildup causes pressure inside the eye. However, both problems can be treated. (See "Treating Eye Problems," below.)

Fortunately, most eye problems related to arthritis and its treatment can be managed or corrected if detected early enough. Here's the typical treatment for each:

dry eyes - artificial tears, humidifiers and sunglasses; avoiding contact lenses and dry conditions

scleritis - glucocorticoid eye drops and systemic anti-inflammatory drugs

cotton wool spots - no treatment needed for spots; however, spots signal the potential presence of other health problems that may require treatment

giant cell arteritis - prednisone, given in high doses until inflammation subsides, can prevent blindness

iritis - glucocorticoid eye drops

cataracts - removal of clouded lens; replacement with a synthetic lens

retinal damage from hydroxychloroquine - discontinuing drug, if eye exam reveals early damage

glaucoma - eye drops or diuretic medication; surgery to drain excess fluid from eyes

To receive a free Arthritis Foundation brochure on rheumatoid arthritis, polymyalgia rheumatica, lupus, hydroxychloroquine, Sjögren's syndrome, ankylosing spondylitis or arthritis in children contact your local Arthritis Foundation office or call 800/283-7800.

Looking for an ophthalmologist in your area? You can search for one online by visiting the American Academy of Ophthalmology Web site (http://www.eyenet.org) - just look for the phrase "Find an Ophthalmologist" on the homepage. If you don't have Internet access, you can contact your state's academy, society or association of opthalmologists. Chances are it's located in the state capital or the largest city.