Uveitis

What uveitis is

The uvea is the pigmented middle layer of the eye between the white outer coat (sclera) and the retina. It has three parts:

• The iris, the colored ring around the pupil.
• The ciliary body, which makes the fluid inside the front of the eye and changes the lens shape for focusing.
• The choroid, a layer of blood vessels that nourishes the retina.

Uveitis is inflammation of any of these, often with spillover into the retina, the vitreous gel or the optic nerve. White blood cells leak into the normally clear fluids of the eye, which blurs vision and damages delicate tissues.

Types of uveitis

Uveitis is also described as acute (sudden, under 3 months), recurrent, or chronic (persistent, needing ongoing treatment).

Symptoms of uveitis

• Eye redness, often concentrated in a ring around the iris.
• Aching eye pain, which may worsen when focusing.
• Sensitivity to light.
• Blurred or hazy vision.
• Floaters: dark spots or strands that move with eye movement.
• Watering.
• An irregular or small pupil.

Anterior uveitis usually affects one eye at a time. Intermediate and posterior uveitis can be painless, so vision changes may be the only clue. Children with juvenile idiopathic arthritis can have chronic uveitis with no symptoms at all, which is why they need regular screening.

Uveitis vs conjunctivitis

What causes uveitis

In many people no cause is found, which is called idiopathic uveitis. Identifiable causes include:

Autoimmune and inflammatory diseases

• HLA-B27 related diseases: ankylosing spondylitis, reactive arthritis, psoriatic arthritis and inflammatory bowel disease. HLA-B27 is found in about half of people with acute anterior uveitis.
• Sarcoidosis.
• Behçet's disease.
• Juvenile idiopathic arthritis.
• Multiple sclerosis.
• Vogt-Koyanagi-Harada disease and sympathetic ophthalmia.

Infections

• Herpes simplex and shingles (herpes zoster).
• Toxoplasmosis, the most common cause of posterior uveitis worldwide.
• Syphilis, tuberculosis, Lyme disease, cytomegalovirus (in weakened immunity), HIV.

Other causes

• Eye injury (traumatic iritis) or eye surgery.
• Certain medicines, including some cancer immunotherapies and bisphosphonates.
• Rarely, cancers such as intraocular lymphoma that mimic uveitis, especially in older adults.

How uveitis is diagnosed

An ophthalmologist examines the eye with a slit-lamp microscope, looking for inflammatory cells and protein ("flare") in the fluid of the front chamber, and dilates the pupil to examine the vitreous and retina. Eye pressure is measured. Additional tests depend on the type:

• Blood tests: HLA-B27, syphilis serology, ACE and lysozyme (sarcoidosis), tuberculosis testing, inflammatory markers.
• Chest X-ray or CT for sarcoidosis or tuberculosis.
• Optical coherence tomography (OCT): detects swelling of the central retina (macular edema).
• Fluorescein or indocyanine green angiography: shows leaking blood vessels.
• Sampling eye fluid for infection or lymphoma in unusual cases.

Doctors usually look for an underlying disease when uveitis is recurrent, affects both eyes, or is intermediate or posterior.

Uveitis treatment

The goal is to control inflammation quickly, prevent complications and preserve vision.

Anterior uveitis

• Steroid eye drops (such as prednisolone acetate), often hourly at first and tapered slowly over weeks. Stopping suddenly can cause a flare.
• Dilating drops (such as cyclopentolate or atropine) relax the eye's focusing muscle, ease pain and prevent the iris sticking to the lens.

Intermediate, posterior and panuveitis

• Steroid injections around or into the eye, or long-acting steroid implants.
• Steroid tablets for severe or both-eye disease.
• Immune-suppressing medicines such as methotrexate or mycophenolate for chronic uveitis, to reduce steroid use.
• Biologics: adalimumab is approved for non-infectious intermediate, posterior and panuveitis; infliximab and others are also used.

Infectious uveitis

Treated with antiviral, antibiotic or antiparasitic medicines, often with steroids added carefully once the infection is controlled.

Steroid drops can raise eye pressure and cause cataracts, so regular monitoring is needed.

Complications

• Glaucoma: raised eye pressure from inflammation or steroid treatment.
• Cataract.
• Macular edema: swelling of the central retina, the most common cause of vision loss in uveitis.
• Synechiae: the iris sticking to the lens.
• Band keratopathy: calcium deposits on the cornea.
• Retinal detachment and scarring.
• Permanent vision loss if untreated.

Outlook

Acute anterior uveitis usually settles within days to weeks with treatment, though it often recurs, especially in HLA-B27 positive people. Chronic, intermediate and posterior uveitis need longer treatment and closer monitoring. With prompt, specialist care, most people keep good vision.

Frequently asked questions

What causes uveitis?

Many cases have no identifiable cause. Known causes include autoimmune and inflammatory diseases (ankylosing spondylitis and other HLA-B27 conditions, sarcoidosis, Behçet's disease, inflammatory bowel disease, juvenile arthritis), infections such as herpes, toxoplasmosis and syphilis, and eye injury or surgery.

Is uveitis serious?

Yes, it can be. Uveitis is a common cause of preventable vision loss. Inflammation can lead to glaucoma, cataract and swelling of the retina if it is not treated promptly. With early treatment from an eye doctor, most people recover well and keep good vision.

What are the first signs of uveitis?

The first signs of anterior uveitis are usually a red, aching eye with sensitivity to light and blurred vision, often in one eye. Intermediate and posterior uveitis may begin with floaters or blurred vision and little pain. Any red, painful eye with light sensitivity needs same-day assessment.

How long does uveitis last?

Acute anterior uveitis usually improves within a few days of starting steroid drops and resolves in about 6 to 8 weeks, as the drops are tapered. Chronic uveitis can last months or years and needs ongoing treatment. Recurrences are common, so learn the early symptoms.

Is uveitis an autoimmune disease?

Uveitis itself is inflammation, but it is often autoimmune in origin. It is associated with autoimmune and inflammatory diseases such as ankylosing spondylitis, sarcoidosis, Behçet's disease and inflammatory bowel disease. Some cases are caused by infections, so testing is important before treatment.