Uveitis is swelling of the middle layer of the eye, which is called the uvea. It may occur from both infectious and non-infectious causes. The uvea supplies blood to the retina. The retina is the light-sensitive part of the eye that focuses the images you see and sends them to the brain. It’s normally red due to its blood supply from the uvea.

Uveitis usually isn’t serious. More severe cases can cause vision loss if not treated early.

The following symptoms may occur in one or both eyes:

  • severe redness in the eye
  • pain
  • dark floating spots in your vision, called floaters
  • light sensitivity
  • blurred vision

The cause of uveitis is often unknown and frequently occurs in otherwise healthy people. It can sometimes be associated with another illness such as an autoimmune disorder or an infection from a virus or bacteria.

An autoimmune disease occurs when your immune system attacks a part of your body. Autoimmune conditions that may be associated with uveitis include:

Infections are another cause of uveitis, including:

Other potential causes of uveitis include:

  • exposure to a toxin that penetrates the eye
  • bruising
  • injury
  • trauma

Your eye surgeon, also called an ophthalmologist, will examine your eye and take a complete health history.

They may also order certain laboratory tests to rule out an infection or autoimmune disorder. Your ophthalmologist may refer you to another specialist if they suspect an underlying condition is causing your uveitis.

There are many types of uveitis. Each type is classified by where the inflammation occurs in the eye.

Anterior uveitis (front of the eye)

Anterior uveitis is often referred to as “iritis” because it affects the iris. The iris is the colored part of the eye near the front. Iritis is the most common type of uveitis and generally occurs in healthy people. It can affect one eye, or it may affect both eyes at once. Iritis is usually the least serious type of uveitis.

Intermediate uveitis (middle of the eye)

Intermediate uveitis involves the middle part of the eye and is also called iridocyclitis. The word “intermediate” in the name refers to the location of the inflammation and not the severity of the inflammation. The middle part of the eye includes the pars plana, which is the part of the eye between the iris and the choroid. This type of uveitis may occur in otherwise healthy people, but it has been linked to some autoimmune diseases such as multiple sclerosis.

Posterior uveitis (back of the eye)

Posterior uveitis may also be referred to as choroiditis because it affects the choroid. The tissue and blood vessels of the choroid are important because they deliver blood to the back of the eye. This type of uveitis usually occurs in people with an infection from a virus, parasite, or fungus. It can also occur in people with an autoimmune disease.

Posterior uveitis tends to be more serious than anterior uveitis because it can cause scarring in the retina. The retina is a layer of cells in the back of the eye. Posterior uveitis is the least common form of uveitis.

Pan-uveitis (all parts of the eye)

When the inflammation affects all major parts of the eye, it’s called pan-uveitis. It often involves a combination of features and symptoms from all three types of uveitis.

Treatment for uveitis depends on the cause and the type of uveitis. Usually, it’s treated with eye drops. If uveitis is caused by another condition, treating that underlying condition may eliminate the uveitis. The goal of treatment is to reduce inflammation in the eye.

Here are the common treatment options for each type of uveitis:

  • Treatment for anterior uveitis, or iritis, includes dark glasses, eye drops to dilate the pupil and reduce pain, and steroid eye drops to reduce inflammation or irritation.
  • Treatment for posterior uveitis may include steroids taken by mouth, injections around the eye, and visits to additional specialists to treat the infection or autoimmune disease. A body-wide bacterial infection is usually treated with antibiotics.
  • Treatment for intermediate uveitis includes steroid eye drops and steroids taken by mouth.

Severe cases of uveitis may require drugs that suppress the immune system.

Untreated uveitis can lead to serious complications, including:

  • cataracts, which is a clouding of the lens or cornea
  • fluid in the retina
  • glaucoma, which is high pressure in the eye
  • retinal detachment, which is an eye emergency
  • a loss of vision

Anterior uveitis will typically go away within a few days with treatment. Uveitis that affects the back of the eye, or posterior uveitis, typically heals more slowly than uveitis that affects the front of the eye. Relapses are common.

Posterior uveitis due to another condition may last for months and can cause permanent vision damage.

Seeking proper treatment for an autoimmune disease or infection can help to prevent uveitis. Uveitis in otherwise healthy people is difficult to prevent since the cause isn’t known.

Early detection and treatment are important to reduce the risk of vision loss, which can be permanent.