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Uveitis

uveitis


Uveitis is inflammation of the uveal tract: the iris, ciliary body and choroid. It is classified according to the part of the uveal tract that it affects and symptoms also vary according to this. Uveitis can be acute (sudden onset), chronic (long-lasting) or recurrent (relapsing). Treatment, often with steroid eye drops, can usually reduce inflammation and ease symptoms. If treatment is not started promptly and/or complications occur, it can be serious and may lead to permanent loss of vision.

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. 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.

What are the different types of uveitis?

Uveitis is classified according to the part of the uveal tract that the inflammation affects:

  • Anterior uveitis is when the inflammation affects the anterior part of the uveal tract at the front of the eye. This can include 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 or eye, mainly the vitreous humour. It can also affect the underlying retina.
  • Posterior uveitis is when the inflammation affects the back of the eye. It can affect the choroid, the head of the optic nerve, and the retina (or any combination of these structures). It includes chorioretinitis, retinitis and neuroretinitis.
  • Panuveitis is when the inflammation affects the whole of the uveal tract.

Uveitis can also be:

  • Acute: the uveitis is of sudden onset and tends not to last very long (less than three months but usually around six weeks).
  • Chronic: which means it is persistent. The uveitis lasts for more than three months and also relapses (comes back) within three months of stopping treatment.
  • Recurrent: the disease can flare up (relapse) and, at other times, it settles down.

The reason why some people develop chronic uveitis is not known. However, it is not thought to be due to inadequate treatment.

How is uveitis caused?

There are many different causes of uveitis and uveitis is associated with a number of other diseases. However, in up to half of cases, no specific cause for uveitis is found. This is known as idiopathic uveitis.

The known causes and associations of uveitis include the following:

Autoimmune and inflammatory diseases

Our immune system normally makes antibodies (small proteins) to attack bacteria, viruses, and other 'germs'. In people with autoimmune diseases, their immune system makes antibodies against the tissues of their body causing damage and inflammation. 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 are associated with uveitis include Behçet's syndrome and rheumatoid arthritis. (See leaflet called 'Rheumatoid Arthritis' for further information about this disease. Behçet's 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.) It is also thought that 'idiopathic' uveitis may actually have an autoimmune basis.

People with some other inflammatory diseases are also more prone to uveitis. Such diseases include ankylosing spondylitis, reactive arthritis (including Reiter's syndrome), sarcoidosis, psoriasis and inflammatory bowel disease (including Crohn's disease) and ulcerative colitis. (Sarcoidosis is a condition causing chronic inflammation in your body, particularly in the lungs where it causes cough and breathing difficulties.) Please see separate leaflets called 'Ankylosing Spondylitis', 'Reactive Arthritis', 'Sarcoidosis', 'Psoriasis', 'Crohn's Disease' and 'Ulcerative Colitis' for more information on these conditions.

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. Infections are a rare cause of uveitis.

Injury to the eye

Uveitis can occur after injury to your eye.

Iatrogenic causes

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

Cancers

Some cancers are associated with inflammation and uveitis. These include leukaemia, lymphoma and malignant melanoma. See separate leaflets called 'Leukaemia - A General Overview', 'Lymphoma - Hodgkin's' and 'Lymphoma - Non-Hodgkin's', and 'Cancer of the Skin - Melanoma' for more information on each of these conditions.

Is uveitis common, who is more prone to get it? How common is uveitis and who gets it?

It mostly affects people between the ages of 20 and 59 and is uncommon in children. However, uveitis can affect anyone of any age. If you have one of the underlying conditions or problems mentioned above, you are at greater risk of developing uveitis.

What are the symptoms of uveitis?

The symptoms 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 develop 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 notice 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 notice 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 symptoms tend to take longer to develop.

How do you diagnose uveitis?

Uveitis is usually suspected on the basis of the symptoms that you have. If your doctor suspects that you have uveitis, you will usually be referred 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.

How do you treat uveitis?

Treatment for uveitis aims to help relieve pain and discomfort in the eye(s), treat any underlying cause (if possible), and to reduce the inflammation. This may 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. However, they can have some side-effects. They can make your pupil appear large, can cause temporary blurred vision and also difficulty with 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 may 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, such as paracetamol, taken by mouth may also help.

Steroid eye drops

Steroid eye drops are used to reduce the inflammation in uveitis. They are usually the main treatment. 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 lead to cataracts or glaucoma.

Steroids by mouth or injection

In severe uveitis, steroids are sometimes given by injection into or around your 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.

Immunosuppressive drugs

If steroid treatment is needed in the longer term to treat uveitis, a second drug known as an immunosuppressive drug may be used. This can help to reduce the amount of steroids needed and/or help to control the uveitis if steroids are not working.

Treatment of underlying conditions and causes

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

Surgery

Occasionally, surgery is needed to treat uveitis (usually chronic uveitis). For example, 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 may also be used to treat the complication of cataracts that can occur (see below).

Newer 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 complications can occur with uveitis?

If uveitis is not treated quickly, it can have serious effects and can lead to permanent loss of vision. It may also lead to complications that can affect your eyesight. If complications are not detected early, they can sometimes have a more detrimental effect on your eyesight than the underlying uveitis.

The complications of uveitis may be caused by the effects of the inflammation inside the eye. However, some of them may also be caused by the steroid treatment used to control the inflammation. Despite this, as a general rule, using enough steroids to control the uveitis will generally give a better outcome than using too few steroids and not controlling the inflammation. 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. Dilating eye drops can sometimes help to prevent synechiae.

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. If glaucoma is not treated, it can lead to visual loss. Glaucoma can also be a side-effect of long-term steroid treatment.

Macula oedema: this is when fluid builds up in the back of your eye around your macula on your retina. It may cause permanent visual loss.

Cataract formation: the inflammation can cause changes in the lens of your eye, and cataract formation. Cataracts may also be caused by long-term steroid treatment. If a cataract worsens and is not treated, it can lead to visual loss.

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?

In general, the sooner treatment for anterior uveitis is started, the better the outlook and, for most people, the quicker it goes away. However, anterior uveitis can recur, especially if it is associated with an underlying illness such as an autoimmune disease or the inflammatory diseases mentioned above. Anterior uveitis can also become chronic in some people, despite early and adequate treatment.

With intermediate or posterior uveitis, it is more likely that the condition will last for a longer time or will be chronic. 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.


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