Uveitis and Iritis

What is uveitis?

Uveitis is inflammation of the uveal tract. The uveal tract is the name given to the part of your eye that is made up of:

• The iris: the part of your eye that gives it colour
• The ciliary body: a small ring-like muscle that sits behind your iris
• The choroid: the layer of tissue between your retina and your sclera, containing blood vessels and a pigment that absorbs excess light

Parts of your eye next to the uveal tract can also be affected by the inflammation. These include:

• The retina: the light sensitive layer lining the interior of your eye
• The optic nerve: the nerve responsible for vision
• The vitreous humour: the jelly-like material that fills the chamber behind your lens
• The sclera: the white outer layer of your eyeball

Uveitis can have an acute (sudden) onset. Acute uveitis tends not to last very long. Uveitis can also be a chronic relapsing condition. Chronic means that it is persistent. Relapsing means that at times the disease flares-up (relapses), and at other times it settles down.

What are the different types of uveitis?

Uveitis can be classified according to the part of the uveal tract that the inflammation is affecting:

• Anterior uveitis is when the inflammation affects the anterior part of the uveal tract. This can be the iris (iritis) or the iris and the ciliary body (iridocyclitis). It is the most common type of uveitis.
• Intermediate uveitis is when the inflammation affects the middle part of the uveal tract. It can also affect the underlying retina.
• Posterior uveitis is when the inflammation affects the choroid and the retina. It includes retinochoroiditis, retinitis and neuroretinitis.
• Panuveitis is when the inflammation affects the whole of the uveal tract.

What causes uveitis?

There are many different causes of uveitis. Uveitis is also associated with a number of other illnesses. However, it is common for no specific cause for uveitis to be found. This is known as idiopathic uveitis. The causes and associations of uveitis can include the following:

Infection

Various types of bacterial, fungal and viral infections can cause inflammation of your eye and uveitis. Infections include herpes simplex, herpes zoster, toxoplasmosis, cytomegalovirus, syphilis, gonorrhoea, tuberculosis and Lyme disease.

Autoimmune disease

The immune system normally makes antibodies (small proteins) to attack bacteria, viruses, and other 'germs'. In people with autoimmune diseases, the immune system makes antibodies against tissues of the body. It is not clear why this happens. Some people have a tendency to develop autoimmune diseases. In such people, something might trigger the immune system to attack the body's own tissues. The 'trigger' is not known. Autoimmune diseases that can lead to uveitis include Reiter's syndrome and Behçets syndrome. Behçets syndrome is a condition that causes recurrent mouth ulcers. It can also affect other parts of your body including your heart, lungs, gut, joints and nervous system. Please refer to the separate leaflet on 'Reactive Arthritis and Reiter's Syndrome' for more information about Reiter's syndrome.

Injury to the eye

Uveitis can occur after injury to your eye.

Iatrogenic causes

'Iatrogenic' refers to either an unforeseen or an inevitable side effect from a medical treatment. In this case, iatrogenic uveitis is usually uveitis that has resulted from eye surgery.

Inflammatory diseases

People who already have an inflammatory disease are more prone to uveitis. Such diseases include sarcoidosis, inflammatory bowel disease such as Crohn's disease and ulcerative colitis, rheumatoid arthritis and ankylosing spondylitis. Sarcoidosis is a condition causing chronic inflammation in your body, particularly in the lungs where it causes cough and breathing difficulties. Please refer to the separate leaflets on each of the other conditions mentioned for more information about them.

Cancers

Some cancers are associated with inflammation and uveitis. These include leukaemia, lymphoma and malignant melanoma. Please refer to the separate leaflets on each of these conditions for more information.

What are the symptoms of uveitis?

The symptoms of uveitis can vary depending on which type of uveitis you have.

Anterior uveitis

This usually affects one eye. The common symptoms are eye pain (usually felt as a dull ache in and around the eye), redness of your eye and photophobia (which means you do not like bright light). You may develop blurred vision or even some visual loss (usually temporary). You may experience headaches and notice that your iris (the part of your eye that gives it colour) is a slightly different colour. Your eye may become watery. The symptoms tend to develop over a few hours or days.

Intermediate uveitis

This usually causes painless blurred vision. It is unusual to experience photophobia and redness of your eye. You may experience floaters and these are a common symptom. Floaters are dark shapes that you see, especially when looking at a brightly illuminated background such as a blue sky. Both eyes are usually affected in intermediate uveitis.

Posterior uveitis

This commonly causes painless blurred vision. In some people, it can also cause severe visual loss. If you have posterior uveitis you may experience floaters, as described above. You may also develop scotomata. Scotomata are small areas of less sensitive, or absent, vision in your visual field. These areas are surrounded by normal sight. It is usual for only one of your eyes to be affected in posterior uveitis and the symptoms tend to take longer to develop.

How is uveitis diagnosed?

Uveitis is usually suspected on the basis of the symptoms that you may have. If your doctor suspects that you have uveitis, they may refer you to an eye specialist for further examination and confirmation.

The doctor may start by testing your vision. This allows them to assess any differences in vision between your eyes. It also means that they can tell if the uveitis is causing your vision to worsen.

The doctor examining your eye will usually use an ophthalmoscope, a hand-held instrument, to examine the interior of your eye. This directs a beam of light into your eye and allows the doctor to examine the inside of your eye where the beam falls. The doctor will usually put in some eye-drops just before the examination. These make your pupils wider so that they can see into your eye more easily. The doctor may also use a special microscope called a slit lamp to examine your eye. If you have uveitis, the doctor will see some specific changes in your eye that allows them to make the diagnosis.

You may also need some other investigations depending on what the doctor thinks is the likely cause of your uveitis. These can include blood tests and x-rays.

What is the treatment for uveitis?

Treatment for uveitis aims to help relieve pain and discomfort in the eye(s), treat any underlying cause and to reduce the inflammation. This should hopefully prevent permanent loss of vision or other complications. Treatment usually includes the following:

Treatment to relieve pain and discomfort

• Cycloplegic eye drops: These are special eye drops that can be used to relieve pain by causing the pupil in your eye to dilate (widen). The drops cause your pupil to dilate by relaxing the muscle in the ciliary body. As a result, pain reduces and the inflamed iris is able to rest and recover. Examples include atropine and cyclopentolate eye drops. They can have some side effects. They can make your pupil appear large, can cause temporary blurred vision and difficulty focusing. When the effect of the drops wears off, these side effects will disappear. The drops need to be used as frequently as every hour when uveitis is first diagnosed. If the drops are not used, the inflammation in the iris can cause it to become 'stuck' to the lens causing permanent scarring.
• Dark glasses: If your symptoms include photophobia (sensitivity to bright light), wearing dark glasses may be helpful.
• Painkillers: Painkillers taken by mouth such as paracetamol may also help.

Steroid eye drops

Steroid eye drops will usually reduce the inflammation in uveitis. They are usually the main treatment. However, steroid eye drops are not usually used if uveitis is caused by a bacterial or viral infection. Although steroid eye drops usually work well, in some cases side effects occur, which are sometimes serious. Therefore, steroid eye drops are usually only prescribed by an ophthalmologist (an eye specialist) who can monitor the situation. Possible side effects that sometimes occur include ulcers on the cornea of the eye which can be very painful and affect your vision. If steroid eye drops are used for long periods of time, they can cause cataracts or glaucoma.

Steroids by mouth or injection

In severe uveitis, steroids are sometimes given by injection into the eye. They can also be given by mouth. Again, these can have side effects if used in the long term. The main side-effects from steroids taken by mouth occur when they are used for more than a few weeks. These include thinning of the bones (osteoporosis), thinning of the skin, weight gain, muscle wasting and an increased risk of serious infection.

Treatment of underlying conditions and causes

Any underlying cause of your uveitis also needs to be treated. This means treating any underlying infection, inflammatory disease or autoimmune disease.

Surgery

Occasionally surgery is needed to treat uveitis. If someone has persistent floaters that are affecting their ability to see, the vitreous humour in the eye can be removed. Floaters tend to develop because of inflammation causing damage to the vitreous humour. Surgery is also used to treat the complication of cataracts that can occur.

New treatments

There are a number of new treatments for uveitis that are currently being investigated. These include drugs called TNF-alpha blockers such as etanercept and infliximab.

What are the complications of uveitis?

If uveitis is not treated quickly, it can have serious effects and can lead to permanent loss of vision. Complications that can sometimes occur with uveitis include:

• Formation of synechiae: synechiae are the name given to the 'bands' of tissue that can form between the iris and the lens due to inflammation if uveitis is not treated promptly.
• Glaucoma: The synechiae that form mean that fluid is not able to drain normally within the eye. This can lead to a build-up of pressure within your eye which can lead to glaucoma. Please refer to the separate leaflet on 'Glaucoma' for more information.
• Cataract formation: The inflammation can cause changes in the lens of your eye and cataract formation. Please refer to the separate leaflet on 'Cataracts' for more information.
• Retinal detachment: The inflammation can cause 'pulling' on your retina so that it 'comes away' or is detached. This can cause you to experience flashing lights, floaters and problems with your vision. If you suspect that you have a retinal detachment, contact your doctor immediately as urgent surgery is often needed.

What is the prognosis (outlook) for uveitis?

The sooner treatment for uveitis is started, the better the outlook and the quicker it goes away. However, uveitis can recur, especially if it is associated with an underlying illness such as an autoimmune disease or the inflammatory diseases mentioned above. Some people who have recurrent uveitis learn to recognise their symptoms. They are given steroid eye drops to keep in reserve and start when their usual symptoms reappear. People who have chronic or recurrent uveitis are usually under the long-term care of an eye specialist and have regular check-ups in the outpatient clinic.

Uveitis caused by infection generally clears up when the infection is treated and does not recur.

Further help and information

Uveitis Information Group
South House, Sweening, Vidlin, Shetland Isles ZE2 9QE
Tel: 01806 577310 Web: www.uveitis.net