UVEITIS
What is Uveitis?
If we think of the eye as a hollow, fluid-filled, 3-layered ball, then the
outer layer is the sclera, a tough coat, the innermost is the retina, the thin
light-gathering layer, and the middle layer is the Uvea. The Uvea is made up of
the iris, the ciliary body and the choroid (see diagram). When any part of the
uvea becomes inflamed then it is called Uveitis.
A big problem, when trying to understand Uveitis, for patients and doctors
alike, is that there are many different types of Uveitis. This is because:
The Uvea is made up of different parts. So if the iris is
affected, the condition and its treatment could be
totally different to when the choroid is affected.
The inflammation in the Uvea very often affects other parts of
the eye such as the retina and so a variety of other
problems can be present to complicate the picture.
Next there are a large number of medical conditions where
Uveitis is a feature amongst the other symptoms of the
disease. e.g. Behcet's Disease, Sarcoidosis and Toxoplasmosis, to
name just three of them.
There are many different types of causes of Uveitis.
The term intraocular inflammation is often used to cover the
spectrum of uveitis conditions. As there is this wide variety of different
conditions and complications, it follows that there are numerous ways that it
presents itself. The degree and type of sight loss and the type of treatment
may vary considerably from patient to patient. Although the potential for
confusion sounds high, as long as it is remembered that Uveitis is actually a
number of different conditions, then it is possible to find out about your own
particular case. It is, of course, very important, for both patients and
doctors, to establish the exact type of Uveitis that exists, as far as it is
possible, early on.
What causes Uveitis?
As just suggested, there are a number of quite different types of causes of
Uveitis.
It may result from an infection such as a virus (e.g. herpes) or a fungus (e.g.
histoplasmosis). It may be due to a parasite such as toxoplasmosis.
It may be related to Autoimmune Disease (with or without involvement of other
parts of the body). This, essentially, is when our immune system recognises a
part of our own body as foreign (albeit a small part, like one type of
protein).
Trauma to the eye, or even the other eye in the past, can lead to Uveitis. In
many cases the cause is said to be unknown. This may well mean that the Uveitis
is of the autoimmune type. The word "idiopathic" may often be used to describe
this group.
Another important way of classifying the different types of Uveitis is by
describing the part of the eye that is affected. Very simply, there may be:
Anterior Uveitis
This affects the front of the eye, normally the iris (iritis) or the ciliary
body (iridocyclitis). Iritis, strictly speaking is an older term for Anterior
Uveitis but is still used frequently. Iritis is by far the most common type of
Uveitis and also the most readily treated. Having said that, iritis is
something that needs quite close monitoring because complications such as
raised eye pressure and cataracts can occur.
Intermediate Uveitis
This affects the area just behind the ciliary body (pars plana) and also the
most forward edge of the retina (see the diagram above). This is the next most
common type of uveitis.
Posterior Uveitis
This is when the inflammation affects the part of the uvea at the back of the
eye, the choroid. Often the retina is affected much more in this group. The
choroid is basically a layer rich in small blood vessels which supplies the
retina.
Tests and examinations
Because of the quite diverse types of causes of Uveitis and also due to the
many other medical conditions associated with it, then you can expect to
receive a number of tests and thorough questioning. All these are
straightforward and painless enough but may seem far removed from your eye
problem, e.g. back X-rays, but as said before, it is important to establish the
correct type of Uveitis so that the best treatment can be planned.
How is Uveitis treated?
The treatment of Uveitis aims to achieve the following:
Relief of pain and discomfort (where present).
To prevent sight loss due to the disease or its complications.
To treat the cause of the disease where possible.
Like the varied nature of uveitis, the treatment of it may
differ from case to case quite considerably. Corticosteroids are often the
mainstay of treatment but now are, importantly, being joined by some other
newer drugs, usually used along with the steroids. Various eye-drops are used,
particularly to treat anterior uveitis.
What will happen to my eyes (prognosis)?
This, once again, varies considerably, but there is a growing confidence,
especially with the newer drug treatments, that the eyesight can be stabilised
over the long term. Uveitis as a disease should be regarded as incurable in the
sense that it will never completely go away, but that is not to say that it can
not be controlled.
For more details you can Email at
retina_uvea@adityajyot.org
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