Iritis

Summary

• Iritis is the inflammation of the iris and sometimes the ciliary body as well.
• This usually occurs in only one eye.
• If treated correctly and early enough, iritis does not result in permanent damage.
• In many cases the cause of iritis is unknown.

Definition

Iritis is the inflammation of the iris (the ring of coloured tissue surrounding the pupil of the eye).

Iritis is the most common form of a family of conditions called uveitis. The uvea extends from the front to the back of the eye and comprises the iris, the ciliary body which is behind the iris(this structure focuses the lens) and the choroid body, which is at the back of the eye surfaces (layer rich in blood vessels that lines the back of the eye and supplies blood to the retina).

Anterior uveitis predominantly involves the iris, but the ciliary body can be involved as well. In this case it is called iridocyclitis.

Cause

Certain medical conditions such as Ankylosing spondylitis, Ulcerative colitis, Crohn's disease and Sarcoidosis are associated with iritis.

It can also result from an infection in another part of the body (such as shingles, chickenpox or the cold sore virus) that spreads to the eye.

Injury to the eye and eye surgery may also bring on an attack of iritis.

In many cases the cause of iritis is unknown.

Symptoms and signs

Symptoms of iritis include:

• Eye pain
• Sensitivity to light
• Redness of the eye typically around the cornea
• Watering of the eye
• Blurred vision
• Floating spots in the field of vision
• A smaller pupil in the affected eye (occasionally)

Generally, the eye is not sticky or crusty. These symptoms are more suggestive of conjunctivitis.

Diagnosis

An ophthalmologist will use an instrument called a slit lamp to examine the inside of the eye and can usually make the diagnosis on the basis of this examination.

Since iritis may be associated with disease elsewhere in the body, the ophthalmologist will require a thorough understanding of your overall health. This may involve consultation with other medical specialists.

The ophthalmologist may also request blood tests, X-rays and other specialised tests to establish the cause of iritis.

Treatment

Eye drops (especially steroids such as prednisolone or dexamethasone) and pupil dilators are medications used to reduce inflammation and pain in the front of the eye.

The steroid drops may need to be instilled frequently (in severe cases, as often as every half hour). Your ophthalmologist will arrange to see you again to assess the progress of the treatment and will, according to the degree of inflammation, decrease or increase the treatment at this stage. If the iritis is severe or non-responsive, a sub- conjunctival steroid injection is used.

Pupil-dilating drops (such as cyclopentolate or atropine) make you feel more comfortable and prevent certain complications of iritis. This prevents the iris sticking to the lens, called posterior synechia. However, you may become more sensitive to bright light, lose the ability to focus on near objects and your vision may become more blurred.

Outcome

Uveitis arising in the front or the middle of the eye (iritis or iridocyclitis) is usually more sudden in onset and generally lasts six to eight weeks. In early stages it can usually be controlled by the frequent use of drops.

Uveitis in the back part of the eye (choroiditis) is usually slower in onset, may last longer and is often more difficult to treat. When uveitis is due to an infection in another part of your body it tends to clear up once the underlying infection is treated.

In most cases complications are rare but they include: glaucoma (high pressure in the eye causing damage), cataracts (clouding of the lens of the eye) and neovascularisation (new blood vessel formation).

If left untreated, inflammation in the eye can lead to permanent damage and even vision loss.

When to call the doctor

If you have been experiencing severe eye pain, blurred vision, sensitivity to light and watering of the eye, or if you notice that one pupil is smaller than the other, you should call your doctor.

Reviewed by Dr L.C. Boezaart

Reviewed by Dr L.Venter, MB Ch B, MMed (Ophth) + FC Ophth SA , December 2010