What Is Uveitis?

Uveitis is a broad term for many problems with your eye. What they have in common is eye inflammation and swelling that can damage eye tissues. That damage can lead to poor vision or blindness. About 10% of legal blindness in the U.S. is linked to this kind of damage.

The word "uveitis" is used because the swelling most often affects the part of your eye called the uvea.

What Is the Uvea?

Your eye is made of layers. The uvea is the middle layer. It's between the white part of your eye — called the sclera — and the inner layers of your eye.

Your uvea contains three important structures:

The iris. That's the colored circle at the front of your eye.

The ciliary body. This is a ring of tissue behind your iris that makes fluid and has muscles that can change the shape of your lens, allowing you to focus.

The choroid. This is a group of blood vessels that give your retina the nutrients it needs. It sits behind the iris and ciliary body.

When you have uveitis, you may also have inflammation beyond the uvea, including in your eye fluid and your retina. That's the light-sensitive tissue at the back of your eye that sends images to your brain.

Types of Uveitis

Which type of uveitis you have depends on where the swelling is.

Anterior uveitis

This is the most common, making up about 80% of cases. It affects the iris, at the front of your eye. It often causes symptoms visible to you and other people. It's the least likely to damage your vision. But if it lasts a long time or keeps returning, you face higher risks of complications.

Intermediate uveitis

This affects your ciliary body and the gel that fills your eye. This type might not be noticeable to others but affects how well you see.

Posterior uveitis

This affects the choroid as well as the retina, in the back of your eye. This form is rare. It poses a greater risk to your vision than anterior or intermediate uveitis.

Panuveitis

This type affects all parts of the uvea, from the front to the back of the eye. It can come with all the symptoms and all the risks of uveitis in the front, middle, and back of the eye. It poses a significant risk to your vision. But the outcome depends on the underlying cause, how severe the inflammation is, and how effectively it's treated.