This article attempts to explain:

• some of the vision threatening complications of uveitis.

• the difference between the direct effects of active uveitis and the effects of complications of the condition.

The inflammation caused by uveitis can directly damage our vision, be it temporary or permanent. However, many patients find that their uveitis may be under good control (or ‘quiet’) but there seem to be ongoing problems requiring all sorts of treatment. This situation causes confusion and comes up time and time again when people contact the UIG. It is well worth trying to understand the difference between active uveitis (frequently referred to as ‘flare ups’) and complications of uveitis.

Specialists in uveitis now assess a patient carefully to look for the signs of early complications.

The treatment we receive is also planned in a way to prevent or minimise any potentially sight threatening complications.

Primarily, the doctors are interested in protecting the patient’s vision. They are more concerned with preventing and treating potential vision robbing effects of the condition, than categorising the exact type and cause of the uveitis, (although this is obviously important as well).

I think that it is true to say that many patients spend a great deal of time trying to:

• pin down a cause for their uveitis.

• work out whether their uveitis is active or ‘flaring up’ or not.

This is perfectly understandable and, of course, it is essential not to tolerate any active inflammation, but it may be useful to consider the indirect effects of uveitis or complications because they can be the dominant factor in many cases.

The main complications most usually seen in the eye clinics are dealt with below, but not necessarily all of them are covered here.

It would be simplest to divide them into those seen in anterior and posterior uveitis.

This can be a result of the inflammation but also can be a temporary problem whilst using drops to enlarge the pupil (mydriatic or dilating drops).

b) Floaters

Debris from inflammatory blood cells can be seen in the visual field as wispy dots or streaks. They can be of nuisance value or can sometimes significantly reduce vision.

c) Persistent pain and redness

This may be a problem even after a ‘flare up’ has been treated and no inflammation is present.

d) Cataracts

Cataracts are very common in the whole population as we grow older and is one of the most common indications for treatment in eye clinics today. Uveitis sufferers are, however, more likely to develop cataracts and at a younger age. This is a problem which can be dealt with but may be more complicated in people with uveitis. The main priority is for the inflammation to be totally under control before and after removal of the cataract.

e) Rise in intraocular pressure (IOP)

The normal eye has a pressure maintained by the flow of fluid through it. If the pressure is raised this can potentially cause glaucoma and is usually controlled with drops. The pressure is easily measured and uveitis sufferers will always have their eye pressure carefully monitored.

Some people’s IOP rises as a result of taking steroid drops (steroid responders). (there is a separate fact sheet uveitis and glaucoma).

f) Synechiae

Sometimes due to the inflammation, the iris becomes ‘sticky’ and it sticks to the lens which sits close behind it. (posterior synechiae). This can distort the shape of the iris and sometimes can influence the IOP (see above).

This can be acute (short term) or chronic(long term).

The macula is a very small area of the retina which is responsible for our detailed or ‘central vision’. Fluid may build up in the retina at this area which may affect the central vision.

Chronic macula oedema can persist in the absence of active uveitis and may be treated with steroid therapy or with immunosuppressants.

b) Vitritis

Inflammation in uveitis may affect the vitreous gel, the clear jelly behind the lens filling the eye to cause vitritis. The result of this can be floaters or a more substantial obstruction of vision if a lot of debris is present.

c) Neovascularisation

Sometimes, as a result of inflammation small, new blood vessels grow at the back of the eye. These vessels are produced as part of the body’s own healing response to injury, but they are unwelcome because they are weak and prone to leak and break down. They can be managed by laser treatment.

Sometimes these new blood vessels form a Sub retinal neovascular membrane, a membrane just behind the retina, which can be treated by laser or may even be surgically removed in a few cases.

d) Loss of Visual field.

Inflammation may result in damaged areas of the retina to produce ‘blind spots’ or scotoma. These may be in the peripheral vision and hardly noticeable but if near the macula, the central vision can be significantly affected.

This ‘list’ of complications should not be a cause of great concern. Much as it can be off putting reading the side effects section of a leaflet that comes with any drug we take nowadays, most people will suffer none or only one or two of all the possible problems.

3. Intermediate Uveitis

Intermediate uveitis varies greatly and so, therefore, does its complications.

This is another reason why there is so much variation in the way individual patients will be managed.

Each type of complication has not been covered in great detail. The UIG has more detailed information about these complications on request. It is hoped that this will make it easier to discuss and question your doctors.