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:
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The iris: the part of your eye that gives it colour
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The ciliary body: a small ring-like muscle that sits behind your iris
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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:
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The retina: the light sensitive layer lining the interior of your eye
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The optic nerve: the nerve responsible for vision
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The vitreous humour: the jelly-like material that fills the chamber behind your lens
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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
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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.
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Dark glasses: If your symptoms include photophobia (sensitivity to bright light), wearing dark glasses may be helpful.
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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:
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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.
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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
References
© EMIS and PiP 2008 Updated: 21 Feb 2008
