Iritis, also called anterior uveitis, is inflammation of the colored part of your eye called the iris. It can also cause inflammation in the space between your iris and the outer layer of your eye called the cornea. Most cases only affect one eye.

Sometimes, it’s not known what causes iritis, but it tends to be associated with a number of health conditions. These include ankylosing spondylitis, ulcerative colitis, and multiple sclerosis.

In this article, we’ll take a deeper look at iritis including the typical symptoms, potential causes, and treatment options.

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Print Illustration by Maya Chastain

Your uvea is the middle layer of your eye beneath your cornea and sclera (the white part of your eye). The uvea contains the following structures:

  • Iris. The pigmented and colored part of your eye.
  • Ciliary body. A ring of muscle behind your iris that changes the shape of your lens when you focus your eye.
  • Choroid. A thin layer of tissue between your sclera and retina (the light-sensitive tissue at the back of the eye).

Inflammation of your uvea is called uveitis. When your iris and the space in front of your iris are affected, the inflammation is called iritis or anterior uveitis.

Iritis tends to be the mildest type of uveitis and often occurs in otherwise healthy people. It primarily affects people ages 20 to 60 and makes up about 50 to 70 percent of all uveitis cases.

Iritis is called acute iritis if it lasts a short time and chronic iritis if it lasts a long time. It’s called recurrent iritis if it returns repeatedly.

The other three types of uveitis include the following:

Intermediate uveitis

Intermediate uveitis causes inflammation of the ciliary body and the vitreous fluid inside your eye. It’s also referred to as iridocyclitis.

Posterior uveitis

Posterior uveitis affects your choroid that contains blood vessels that supply blood to the back of your eye. It tends to be more serious than iritis, but is also the least common form of uveitis.

Panuveitis

Panuveitis is characterized by inflammation in all three layers of your uvea. It tends to cause a combination of symptoms from the other three types of uveitis.

Iritis can develop in one eye or both. Symptoms can include:

Under a special microscope called a slit lamp, your ophthalmologist may be able to see white blood cells in the anterior chamber. This is the space between your iris and cornea.

Symptoms of iritis can be similar to pink eye (conjunctivitis). But if you have significant pain or light sensitivity, it’s more likely that you could have iritis.

Iritis is caused by inflammation in your eye. Inflammation is your body’s way of responding to tissue damage or foreign invaders.

Most of the time, the exact cause of iritis isn’t known. It’s thought to be triggered by immune responses, genetic factors, and infections.

In about 1 in 5 cases, it’s attributed to blunt force trauma of the eye. In this case, it’s called traumatic iritis.

Risk factors

Iritis not caused by an injury is associated with a number of diseases. For example, about half of people with ankylosing spondylitis experience at least one case of iritis or uveitis.

Some of the other conditions that may increase the risk of iritis include:

Eye doctors diagnose iritis by performing an eye examination and checking your medical history. Your doctor may order lab tests to rule out infections and autoimmune conditions.

The types of tests your doctor may perform during an eye exam include:

  • Slit-lamp exam. During a slit-lamp exam, your eye doctor will use a special microscope to examine the structures inside your eye. This is the primary way to diagnose iritis.
  • Visual acuity test. A visual acuity test is a classic eye chart exam that involves reading smaller and smaller letters to test your visual acuity.
  • Funduscopic exam. Your eye doctor will put eye drops in your eyes to dilate your pupils. They will then inspect the back and inside of your eye using a special light.
  • Ocular pressure. An ocular pressure test helps your eye doctor measure the pressure in your eye by gently touching your eye with a special instrument.

Treatment for iritis primarily aims to reduce inflammation in the eye and prevent complications.

Your physician may not order any other tests if you have one episode of mild iritis. But if you have repeated episodes or has severe uveitis your physician may order labs or imaging studies.

Treatment typically includes the following types of medication.

Corticosteroid eye drops

Your eye doctor will likely give you corticosteroid eye drops to reduce inflammation. The most common corticosteroid prescribe is prednisolone acetate.

Dexamethasone and prednisolone sodium phosphate are also commonly prescribed. You’ll typically go to a follow-up appointment about a week later.

Topical cycloplegics

Cycloplegics reduce pain due to spasms of the ciliary muscles behind the iris. The most commonly prescribed medication in this class is homatropine.

With proper treatment from your eye doctor, iritis has a good outlook.

However, if you don’t seek prompt medical treatment you’re at an increased risk of developing complications that could lead to vision loss. These complications can include:

  • cataracts
  • glaucoma
  • inflammation of the gel-like fluid in your eye (vitritis)
  • retinal inflammation (retinitis)
  • swelling in the back of your eye (macular edema)
  • calcium accumulation on your cornea (band keratopathy)
  • attachment of your iris to your lens — this can result in adhesions, causing your pupil to be irregular

To minimize your risk of developing complications, it’s important to visit an eye doctor within 24 hours if you suspect iritis. Once the condition stabilizes, be sure to stick to your doctor’s follow-up recommendations and instructions.

Specific symptoms that should prompt you to seek medical attention include:

  • eye pain
  • tearing
  • light sensitivity
  • vision loss
  • a red eye in the absence of trauma

Iritis is inflammation of your iris that often develops with no apparent cause. Autoimmune reactions, genetic factors, and injuries can all contribute to the development of iritis, but the exact cause isn’t usually known.

Iritis can cause symptoms such as light sensitivity, blurry vision, and pain. If you suspect you may have iritis, it’s important to seek medical attention. Early diagnosis and treatment will reduce the risk of complications and possible vision loss.