Anterior uveitis (iritis): symptoms, causes and treatment

The uvea is the middle layer of the eye and includes the iris (the coloured part), the ciliary body and the choroid. CKS defines uveitis, also known as iritis, as inflammation of the uveal tract. It is classified by the part of the eye affected: anterior (front), intermediate (middle), posterior (back) or panuveitis (all parts).

Anterior uveitis involves the iris and the front part of the ciliary body. CKS describes it as the most common type, while posterior uveitis is the least common. Uveitis can also be classified by how fast it starts, how long it lasts and its course. Acute episodes resolve within 3 months, recurrent episodes are separated by quiet periods, and chronic disease relapses quickly after treatment stops.

The NHS lists the symptoms of uveitis as eye pain, which may feel worse when reading, red or watery eyes, reduced or blurred vision, sensitivity to light, and lights in the corner of the eyes or dark spots (flashes and floaters). Symptoms can develop in hours and days or more gradually over weeks and months, and sometimes uveitis causes no symptoms at all.

CKS describes the typical acute anterior pattern as a dull ache that is worse when the pupil constricts, redness, photophobia, blurred vision and watering. The chronic form may show only blurred vision and mild redness, with pain and light sensitivity usually mild. Intermediate and posterior uveitis tend to cause blurred vision and floaters without much pain or redness.

• A painful, red eye, with ache that may be worse reading or in bright light.

• Sensitivity to light and watering of the eye.

• Blurred or reduced vision, floaters or flashes.

• In chronic cases, blurred vision with only mild redness.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you have eye pain, sensitivity to light, changes in vision such as flashing or blurring, or very red eyes in one or both eyes. It says to go to A&E or call 999 if you cannot see (loss of vision).

The NHS notes that other conditions can cause similar symptoms, including glaucoma, other infections or inflammation such as conjunctivitis, keratitis or scleritis, and an eye injury. This is one reason a painful red eye with light sensitivity needs examination by someone with the right equipment.

The NHS says that depending on what is causing your uveitis and how severe it is, you will usually be prescribed a combination of medicines to get rid of any infection, reduce inflammation, and relax the eye and reduce pain. If it is very severe or keeps coming back you may also be offered immunosuppressant medicines, TNF inhibitors, light (laser) treatment, cryotherapy or surgery on part of the eye.

After you have started treatment you will be seen again by an ophthalmologist to see how treatment is working, check for side effects and check for complications such as vision loss.

The NHS says that in most cases the cause is unknown. Recognised causes include autoimmune conditions such as multiple sclerosis and ankylosing spondylitis, infections including herpes simplex, herpes zoster (shingles) and toxoplasmosis, an injury to the eye and, rarely, a growth in the eye. CKS likewise lists systemic autoimmune disorders, infection, trauma and neoplasia as causes.

If uveitis keeps recurring, or if you have back stiffness, bowel symptoms, skin conditions or other systemic features, the ophthalmologist or your GP may look for an underlying condition. Many people have a single episode with no identified cause.

CKS says uveitis should be suspected in people with typical symptoms, and that findings on examination can include redness concentrated around the cornea, reduced vision, a small pupil and light sensitivity. Intraocular pressure may be normal or slightly lower in the acute phase, then rise as inflammation subsides.

The diagnosis must be confirmed by slit-lamp examination of the front of the eye and a dilated fundus exam. These are done by an eye specialist rather than in routine primary care, which is why CKS advises that uveitis should be managed by an ophthalmologist, with shared care arrangements sometimes allowing treatment to be continued and monitored in primary care.

NICE CKS classifies uveitis by the part of the eye affected. Anterior uveitis is the most common type and posterior uveitis the least common.

The NHS says uveitis is rare, that it is important to treat it early to avoid long-term complications such as vision loss and blindness, and that it usually gets better quickly with treatment but can come back over time.

NICE CKS classifies uveitis by its course. An acute episode is a sudden onset of inflammation that resolves within 3 months. Recurrent uveitis means repeated episodes separated by periods of inactivity without treatment for 3 months or more. Chronic uveitis relapses promptly, within 3 months, after treatment is stopped.

The NHS says that if a GP thinks you have uveitis they will refer you to an eye specialist (ophthalmologist), and you will usually be seen within 24 hours so that you can start treatment quickly. NICE CKS advises an urgent, same-day ophthalmology referral for suspected uveitis.

Private ophthalmology services also offer slit-lamp examination and treatment. Whichever route you use, the aim is the same: confirm the diagnosis, treat promptly and arrange follow-up.