Iridocyclitis

What iridocyclitis means

The word combines irido- (iris), cyclo- (ciliary body) and -itis (inflammation). The iris is the colored ring that controls pupil size. The ciliary body sits just behind it, makes the clear fluid that fills the front of the eye (aqueous humor) and contains the muscle that focuses the lens.

Together with the choroid at the back of the eye, the iris and ciliary body make up the uvea, the eye's middle, blood-vessel-rich layer. Doctors classify uveitis by where the inflammation sits:

In practice, iritis and iridocyclitis are both called anterior uveitis and are treated the same way. Anterior uveitis is the most common type, making up roughly three quarters of uveitis cases seen by eye specialists.

Symptoms of iridocyclitis

Acute iridocyclitis usually affects one eye and comes on over hours to a day or two:

• Redness that is most intense in a ring around the cornea (ciliary flush), rather than spread over the white of the eye as in conjunctivitis
• Deep, aching eye pain that can spread to the brow or temple
• Sensitivity to light that is often painful. Light makes the inflamed iris muscle contract
• Blurred or hazy vision from inflammatory cells floating in the fluid at the front of the eye
• Watering but without the sticky discharge of an infection
• A small or irregularly shaped pupil, because the inflamed iris can stick to the lens

Chronic iridocyclitis is different. It can be almost painless and white, especially in children with juvenile idiopathic arthritis, and may only be found on a routine eye exam once damage has begun.

Iridocyclitis vs conjunctivitis vs acute glaucoma

What causes iridocyclitis

In about half of people no cause is found even after testing. This is called idiopathic anterior uveitis. The rest fall into a few groups.

Is iridocyclitis autoimmune?

Often, yes. The largest known group is immune-mediated, where the body's immune system attacks the eye's own tissues:

• HLA-B27-associated disease: the gene marker HLA-B27 is found in up to half of people with acute anterior uveitis. Many also have or later develop ankylosing spondylitis, reactive arthritis, psoriatic arthritis or inflammatory bowel disease. These attacks are typically sudden, one-sided and recurrent, and may switch eyes.
• Juvenile idiopathic arthritis: causes chronic, quiet iridocyclitis in children, especially girls with few affected joints and a positive ANA blood test.
• Sarcoidosis: can cause chronic inflammation in both eyes with large "mutton-fat" deposits on the back of the cornea.
• Behcet's disease, multiple sclerosis and tubulointerstitial nephritis with uveitis (TINU) are less common links.

Infections

• Herpes simplex and varicella-zoster (shingles) viruses: often cause one-sided iridocyclitis with raised eye pressure. Shingles near the eye, especially on the tip of the nose, raises the risk.
• Cytomegalovirus, syphilis, tuberculosis and Lyme disease: rarer but important to find, because they need anti-infective treatment rather than steroids alone.

Injury and surgery

Blunt trauma, such as a ball or fist to the eye, can cause traumatic iritis within a few days. Mild inflammation after cataract and other eye surgery is expected and treated routinely.

Medicines

Some drugs can trigger anterior uveitis, including certain bisphosphonates for bone thinning, some immune checkpoint inhibitors for cancer, and rifabutin.

How iridocyclitis is diagnosed

An eye doctor (ophthalmologist or optometrist with uveitis training) diagnoses it with a slit-lamp microscope. The key findings are:

• Cells and flare: white blood cells and protein floating in the fluid of the front chamber. Doctors grade these from 0 to 4+ to track response to treatment.
• Keratic precipitates: clumps of inflammatory cells stuck to the back of the cornea.
• Synechiae: places where the iris has stuck to the lens.
• Eye pressure: measured at every visit. It can be low during inflammation and high from the disease or from steroid drops.

The doctor will also dilate the pupil to check the back of the eye for intermediate or posterior uveitis.

A first, one-sided, typical attack in a healthy adult often needs no blood tests. Testing is usually done for attacks that are recurrent, affect both eyes, are granulomatous (mutton-fat type) or do not respond to treatment. Tests may include HLA-B27, syphilis serology, a chest X-ray or CT for sarcoidosis and tuberculosis, ACE level, and urinalysis for kidney involvement. Back pain and stiffness that improve with exercise may prompt referral to a rheumatologist.

Treatment of iridocyclitis

Treatment aims to stop inflammation quickly, relieve pain and prevent complications.

Steroid eye drops

Prednisolone acetate or a similar steroid drop is the mainstay. Drops are often used every hour at first, then tapered slowly over several weeks as the inflammation settles. Stopping suddenly can cause a rebound flare, so follow the exact taper your doctor gives you.

Dilating drops

Cyclopentolate or atropine drops relax the ciliary muscle, which eases the aching and light sensitivity. They also keep the pupil moving so the iris does not stick permanently to the lens. They blur near vision while you use them.

Stronger or longer-term treatment

• Steroid injections around or into the eye, or steroid tablets, for severe inflammation or when drops are not enough
• Steroid-sparing immunosuppressants such as methotrexate, or biologic medicines such as adalimumab, for recurrent or chronic disease, often managed with a rheumatologist
• Antiviral or antibiotic treatment when herpes, syphilis, tuberculosis or another infection is found
• Eye pressure-lowering drops if pressure rises

What you can do

• Wear sunglasses and avoid bright light while the eye is sore.
• Use every drop exactly as prescribed and keep all follow-up appointments, often within a week at first.
• Do not use leftover steroid drops for a new red eye without being examined. Steroids can make herpes infections much worse.
• Learn your early warning signs if you have had attacks before. Many people can tell within hours, and early treatment shortens episodes.

Complications

Most acute attacks clear within 4 to 8 weeks with treatment and leave no damage. Untreated, recurrent or chronic inflammation can cause:

• Glaucoma: raised eye pressure from blocked drainage or steroid use
• Cataract: clouding of the lens from inflammation and long-term steroids
• Posterior synechiae: a stuck iris that can block fluid flow and cause sudden pressure rise
• Band keratopathy: chalky calcium deposits across the cornea in chronic cases
• Cystoid macular edema: swelling at the center of the retina, a leading cause of vision loss in uveitis
• Low eye pressure (hypotony) from a damaged ciliary body in severe chronic disease

Outlook and recurrences

The outlook for acute iridocyclitis is good when treatment starts early. About half of people with HLA-B27-related disease have repeat attacks, sometimes several a year. Chronic disease, especially in children with arthritis, carries more risk to vision and needs regular monitoring for years. Children with juvenile idiopathic arthritis are screened by an eye doctor every few months even when the eyes look normal.

Frequently asked questions

What is the meaning of iridocyclitis?

Iridocyclitis means inflammation of the iris and the ciliary body, two parts of the eye's middle layer (the uvea). It is a form of anterior uveitis. It causes a red, painful, light-sensitive eye and blurred vision and needs treatment from an eye doctor.

Is iridocyclitis autoimmune?

Often it is. Many cases are linked to immune conditions such as ankylosing spondylitis, psoriatic arthritis, inflammatory bowel disease, juvenile arthritis and sarcoidosis, and to the HLA-B27 gene marker. Other cases follow viral infections, eye injury or surgery, and in about half no cause is found.

Is iridocyclitis the same as iritis?

They are very similar. Iritis is inflammation of the iris alone, while iridocyclitis also involves the ciliary body just behind it. Both are types of anterior uveitis, cause the same symptoms and are treated the same way, so the terms are often used interchangeably.

What is the treatment of iridocyclitis?

Treatment is usually steroid eye drops to calm the inflammation, tapered over several weeks, plus dilating drops to ease pain and stop the iris sticking to the lens. Severe or recurring cases may need steroid injections, tablets or immune-suppressing medicines, and infections are treated with antivirals or antibiotics.

How long does iridocyclitis last?

An acute attack usually settles within 4 to 8 weeks with treatment, with symptoms easing in the first few days. Stopping drops too early often causes a flare. Chronic iridocyclitis can last months or years and needs long-term monitoring.

Can iridocyclitis cause blindness?

It rarely causes blindness when treated promptly. Vision loss usually comes from complications of untreated or long-lasting inflammation, such as glaucoma, cataract or swelling of the macula. Early treatment and regular eye pressure checks greatly lower that risk.

Is iridocyclitis contagious?

No. Even when a virus such as herpes triggers it, iridocyclitis itself does not spread from person to person. A red eye with sticky discharge that spreads between people is more likely to be conjunctivitis.