Anterior uveitis

The symptoms of anterior uveitis include:

• a painful red eye – the pain can range from mild aching to intense discomfort; reading or other tasks that require you to focus your eye can make the pain worse
• blurred or cloudy vision
• a small pupil
• the iris (the coloured part of the eye) can be a slightly different colour than usual
• sensitivity to light (photophobia)
• floaters (shadows that move across the field of vision)
• headaches

Intermediate uveitis

The most common symptoms of intermediate uveitis are:

• floaters
• blurred vision

In four out five cases of intermediate uveitis, only one eye is affected. Symptoms of pain, redness and photophobia aren't usually present in cases of intermediate uveitis.

Posterior uveitis

The symptoms of posterior uveitis include:

• floaters
• blurred vision
• loss of peripheral vision – the ability to see objects at the side of your field of vision
• seeing flashing lights

When to seek medical advice

Contact your GP as soon as possible if you have persistent eye pain or you notice an unusual change in your vision, particularly if you've had previous episodes of uveitis.

The sooner uveitis is treated, the less likely it is that a person will have permanent problems with their vision.

Some cases of uveitis are thought to be caused by inflammation.

When your body is under threat from infection, your immune system (the body’s natural defence against infection and illness) reacts by sending infection-fighting white blood cells to the site of the infection. This causes the affected area to become warm, red and swollen. This is what’s known as inflammation.

Sometimes, the inflammation associated with uveitis is in response to a real infection. This is known as infectious uveitis. However, uveitis often occurs for no apparent reason as the result of the immune system malfunctioning and triggering the process of inflammation even though no infection is present. This is known as non-infectious uveitis.

The differences between infectious and non-infectious uveitis are explained in more detail below.

Infectious uveitis

The most common causes of infectious uveitis are:

• the herpes simplex virus – the virus that's responsible for cold sores and genital herpes (a sexually transmitted infection [STI] that causes painful blisters to appear on the genitals)
• the varicella-zoster virus – the virus that causes chickenpox
• cytomegalovirus – a common type of viral infection that usually only causes noticeable symptoms in people with weakened immune systems, such as those with HIV and unborn babies
• toxoplasmosis – an infection that's spread by parasites; it usually only causes noticeable symptoms in people with a weakened immune system and in unborn babies

Less common causes of infectious uveitis include:

• Lyme disease – a bacterial infection that's spread by insects
• syphilis – a type of STI that's now uncommon since the introduction of antibiotics
• tuberculosis – a bacterial infection that mainly affects the lungs

Non-infectious uveitis

Many cases of non-infectious uveitis develop in people who have an underlying autoimmune condition (where the immune system mistakenly attacks healthy tissue). Autoimmune conditions that are known to trigger the symptoms of uveitis in some people include:

• ankylosing spondylitis – an autoimmune condition that mainly affects the spine
• reactive arthritis – a type of arthritis that can affect the joints, genitals and eyes
• conditions that cause bowel inflammation, such as Crohn’s disease and ulcerative colitis
• psoriasis – a skin condition that's caused by the immune system disrupting the normal production of skin cells
• multiple sclerosis – an autoimmune condition that mainly affects the nerves
• Behçet’s disease – a rare condition that causes mouth ulcers and genital ulcers

Other causes of non-infectious uveitis include:

• trauma or injury to the eye(s)
• some types of cancers, such as lymphoma, although this is a very rare cause of uveitis

Idiopathic uveitis

Around 1 in 3 people with uveitis have no history of an underlying autoimmune condition. This is known as idiopathic uveitis. Most experts suspect that the immune system plays a role in cases of idiopathic uveitis, although the exact nature of the role remains unclear.

Now read about getting a diagnosis for uveitis.

Your GP will examine your eyes and ask you about your symptoms and your relevant medical history.

If a diagnosis of uveitis is suspected, it's likely that you'll be referred for an immediate appointment with an ophthalmologist (a doctor who specialises in treating eye conditions).

Slit-lamp exam

The ophthalmologist should be able to confirm a diagnosis of uveitis using a piece of equipment called a slit-lamp. A slit-lamp consists of a microscope and a powerful beam of light. The ophthalmologist will use the light to illuminate your eye before examining your eye under the microscope to check for any abnormalities.

If you have uveitis, you'll have large number of white blood cells inside your eye. They will appear as a hazy fluid when studied under the slit-lamp. Noting where the fluid is located within your eye will help the ophthalmologist to determine whether you have anterior, intermediate or posterior uveitis.

Now, read about treating uveitis.

Infectious uveitis

If the cause of your uveitis is known to be an underlying infection, such as the herpes simplex virus, treating the underlying infection should relieve the inflammation in your eyes.

In England, viruses are the most common cause of infectious uveitis (see Uveitis - causes for more information), which usually responds well to treatment with antiviral medications or antibiotics.

Non-infectious uveitis

Corticosteroids are the main type of medication used to treat non-infectious uveitis. They work by disrupting the normal functioning of the immune system so that it no longer releases the chemicals that cause inflammation. Corticosteroids are available in a number of forms, which are described below.

Corticosteroid eye drops

Corticosteroid eye drops are usually the first treatment to be recommended for non-infectious uveitis. Depending on the severity of your symptoms, the recommended dose can range from having to use eye drops every hour, to once every two days.

You may experience temporary blurred vision after using corticosteroid eye drops. If this happens, don't drive or operate machinery until your vision returns to normal.

Don't stop using your eye drops until your GP or ophthalmologist advises that it's safe to do so, even if your symptoms disappear. Stopping treatment too soon could lead to your symptoms returning.

Corticosteroid injections

If your symptoms fail to respond to corticosteroid eye drops, you may need to have a corticosteroid injection.

Corticosteroid injections are also often required to treat cases of posterior uveitis because this type of uveitis doesn't usually respond well to other treatment.

The injection is not given directly into the eye because there's a risk of damaging the eye. Instead, the injection is given to the side of the eye. Local anaesthetic is used to numb your eye and surrounding tissue so that you won't feel any pain or discomfort.

You'll usually require one injection every two to three weeks until your symptoms start to improve.

Corticosteroid injections rarely cause significant side effects.

Oral corticosteroids

Oral corticosteroids (tablets or capsules) are the strongest form of corticosteroids. While they work well in relieving inflammation, oral corticosteroids can cause a wide range of side effects. Therefore, they're only recommended if uveitis is affecting both of your eyes or if it's interfering with your daily activities and other treatments haven’t worked.

Oral corticosteroids may also be recommended if it's thought that uveitis may pose a risk of causing permanent damage to your vision (see Uveitis - complications for more information).

How long you'll have to take oral corticosteroids will depend on how well you respond to treatment and whether you have an underlying autoimmune condition. Some people only need a three- to six-week course, while others need to have a course lasting months or possibly years.

Side effects of oral corticosteroids that are used on a short-term basis (less than three months) include:

• an increased appetite
• weight gain
• insomnia (difficulty sleeping)
• fluid retention
• mood changes, such as feeling irritable or anxious

Side effects of oral corticosteroids that are used on a long-term basis (longer than three months) include:

• osteoporosis (fragile bones)
• high blood pressure (hypertension)
• type 2 diabetes
• weight gain
• increased vulnerability to infection
• cataracts and glaucoma
• thinning of the skin
• bruising easily
• muscle weakness

To minimise the impact of side effects, you will be prescribed the lowest possible dose that's thought to be effective enough to control your symptoms.

Don't suddenly stop taking your oral corticosteroids. If your GP or ophthalmologist decides to end your treatment, they'll gradually reduce the amount of corticosteroids that you're taking.

Immunosuppressants

A very small number of people with uveitis fail to respond to the treatments described above. In such circumstances, immunosuppressants may be recommended. Immunosuppressants are a type of medication that suppress (control) the immune system and disrupt the process of inflammation.

Side effects of immunosuppressants include:

• hair loss
• skin rash
• itchy skin
• numbness or tingling in different parts of your body
• loss of appetite
• nausea and vomiting
• high blood pressure
• headaches 

Taking immunosuppressants will make you more vulnerable to infection, so avoid close contact with anyone who has a known infection.

You should also report any symptom of a potential infection, such as a high temperature or inflammation in other parts of your body, to your GP.

People with chronic (long-term) uveitis are most at risk of developing complications of uveitis.

Complications are also more likely to occur in older adults who are over 60 years old.

The main complications of uveitis are:

• glaucoma
• cataracts
• cystoid macular oedema

The conditions are described below.

Glaucoma

Untreated uveitis can cause the iris (the coloured part of the eye) to stick to the front surface of the lens (the transparent structure that focuses the light that enters your eye). This prevents fluid draining through the pupil and it increases the pressure inside the eye.

The raised pressure inside your eye can damage the optic nerve (the light-sensitive layer of tissue at the back of the eye which transmits images to the brain) and disrupt your normal vision, such as causing misty vision and rings or halos to appear around lights. This is known as glaucoma.

Treatment options for glaucoma include:

• eye drops
• laser treatment
• surgery

Cataracts

The inflammation inside the eye that's associated with uveitis can sometimes irritate the lens of the eye, causing cloudy patches on the surface of the lens to develop. The cloudy patches are known as cataracts. They can cause symptoms such as:

• blurred vision
• problems seeing clearly at night
• colours appearing unusually faint

Cataracts are usually treated using surgery to remove the affected lens and replace it with an artificial one.

For more information, see the topics about Cataracts and Cataract surgery.

Cystoid macular oedema 

Cystoid macular oedema is a complication that can affect some people with chronic uveitis.

Prolonged inflammation can result in a build-up of fluid inside the retina. This can disrupt its ability to function normally and lead to a painless loss of central vision, i.e. you'll notice a black spot in your field of vision.

Cystoid macular oedema can be treated using corticosteroid eye drops to reduce inflammation inside the eye and disperse the fluid inside the retina. 

In some cases, a person’s vision will recover once treatment is initiated. However, this isn't always the case in severe cases of cystoid macular oedema. Hence the condition is a leading cause of visual impairment in people with chronic uveitis.