Rheumatoid arthritis is a type of autoimmune arthritis. It occurs when your immune system mistakenly attacks the tissues that line the insides of your joints, which leads to swelling and pain in the affected joints. Rheumatoid arthritis can lead to serious joint problems like deformities, but it can affect other tissues, too, like your eyes. Rheumatoid arthritis sufferers are at risk of glaucoma, a sight-threatening eye disease. Here are four things you need to know about glaucoma.

What is glaucoma?

Glaucoma is an eye condition characterized by abnormally high intraocular pressure. This high pressure can damage your optic nerve, a nerve in the very back of your eye that transmits images to your brain. This nerve is essential to sight, so when it gets damaged, people experience decreased vision or even complete blindness.

This condition develops slowly and without any major warning signs, so it may be several years before you notice that your vision is impacted. The disease affects the peripheral (side) vision first, which is not very noticeable. Eventually, the central (front) vision is affected, and it's at this point that people realize that something is wrong. 

How does rheumatoid arthritis cause glaucoma?

Rheumatoid arthritis doesn't directly cause glaucoma, but one of the drugs commonly used to treat it does. Corticosteroids are a common anti-inflammatory drug, but in addition to easing the inflammation in your sore joints, they can increase the pressure inside your eyes.

Fluid within your eyes drains out of your eyes through a series of tubes known as the trabecular meshwork. When you take corticosteroids, these tubes can become clogged with water and glycosaminoglycans, a type of sugar. These clogs prevent your intraocular fluid from draining out like it should, and since this fluid gets trapped inside your eye, the pressure increases.

Is glaucoma a common complication?

The exact prevalence of glaucoma among corticosteroid users isn't known. This is because glaucoma is asymptomatic in the early stages, and most patients don't have their intraocular pressure checked.

One study of clinically healthy people found that one-third developed a moderate increase in intraocular pressure following four to six weeks of daily corticosteroid use. The same study reported that 4% to 6% of people developed a severe increase in intraocular pressure. These findings suggest that glaucoma is likely underreported in people taking corticosteroids for rheumatoid arthritis.

To protect your eyes, make sure to have your optometrist check your intraocular pressure, even if you haven't noticed any vision problems. Intraocular pressure can increase within two to six weeks of starting a corticosteroid regimen, according to NIH, so don't delay this screening.

Can glaucoma be treated?

Once your vision has been damaged by glaucoma, it can't be repaired. Treatment focuses on lowering the intraocular pressure quickly to halt further damage to the optic nerve and save any remaining vision.

Stopping corticosteroids can normalize your intraocular pressure in as little as a few weeks, according to NIH. Since you need this medication to control your rheumatoid arthritis, you'll need to ask your rheumatologist about other options. Many other medications are available to treat rheumatoid arthritis, like non-steroidal anti-inflammatory drugs or disease-modifying anti-rheumatic drugs.

If you can't stop taking corticosteroids, your optometrist can find other ways to lower your intraocular pressure. Medicated eye drops can be given to help fluid flow out of your eyes; you'll need to use these eye drops every day. If these eye drops aren't enough, you may need to have surgery. The goal of surgery is to open up your clogged drainage ducts and allow fluid to flow out of your eyes.

If you have rheumatoid arthritis and are taking corticosteroids to control your symptoms, make sure to see an optometrist at a clinic like Montgomery Eye Center regularly to be screened for glaucoma.