What is the connection between dry eyes and inflammation?
It’s easy to imagine that dry eyes have a simple cause, like allergies, dry air, or worn contact lenses. And sometimes it’s true. But if your eyes are dry, irritated, or sore for a long time, it may continue.
There is a complicated connection between your body’s immune system and your eyes. Inflammation, your body’s response to sores and germs, can contribute to dry eyes. In turn, dry eyes can make eye inflammation worse.
This is why doctors sometimes refer to dry eye as a “vicious cycle of inflammation.”
What is Inflammation?
When your body’s cells are damaged – by injury, bacteria, or a toxic chemical – your immune system sends lots of white blood cells to the injured area. These cells trigger an inflammatory response to repair damaged tissue.
During this process, blood vessels leak fluid into the area. This can make it red, hot, swollen, and painful. And the cells there might not function properly while the inflammation continues.
What is the link between inflammation and dry eye?
When there is inflammation of the tear glands, cornea, or conjunctiva (outermost layers of your eyes), your body may not produce enough tears. Or your tears won’t be made of the right mix of water, oils and salts. These changes dry out your eyes.
When your eyes aren’t well lubricated, they aren’t as effective at removing dirt, dust, and germs. This makes you more likely to get small cuts on the outer surface of your eye (called corneal abrasions) or infections.
Stress to your eyes, whether it’s an infection or a scratch on your cornea, then triggers an immune response from your body. This inflammation is your body’s attempt to heal your eye. But it can make dry eyes worse.
Research has shown that over time, eye inflammation can cause not only temporary changes in your tears, but also long-term changes in the nerves in your eyes. Long-term inflammation can also cause other cells in your eyes to die, leading to long-lasting eye conditions.
For years, the most common treatment for dry eyes was artificial tears and other ointments that keep the surface of your eyes moist. These remedies, along with others like avoiding smoking and wearing eye protection, still work for some people with milder cases of dry eye. Doctors may also prescribe watery medications, eye inserts that lubricate your eyes, or special contacts to keep your eyes moist.
But with scientists understanding of dry eye as an inflammatory disease, researchers have increasingly focused on drugs that target your immune system.
Many drugs your doctor might prescribe to treat dry eye by blocking the immune activity that makes your eye inflamed. When the inflammation stops, normal tear production can resume. Some of the anti-inflammatory drugs used to treat dry eye include: