What Does Uveitis Mean?
The simplest definition of uveitis is inflammation of the uvea, which is essentially an inner layer in the eyeball. The eyeball is literally a ball, with a tough outer layer, called the sclera that protects it as it sits in the bony socket of the skull. In the centre of the eyeball is a gel-like fluid called the vitreous humour. The inner surface of the eyeball that meets this fluid contains the retina, with its photoreceptor cells that are responsible for our sense of sight. If you can imagine the layer in between the retina and the sclera, which contains the muscles of the eye (the ciliary body), the blood supply (the choroid), and the iris (the coloured part of the eye that’s either blue, grey, green, hazel or brown) – that is the uvea.
When the uvea becomes inflamed, the uveitis that results causes the eye to become very red, inflamed and swollen and pus can sometimes be seen inside the pupil. It is a distressing and painful condition that can be caused by an infection, or an inflammatory condition that originates in a part of the body not connected with the eye.
What Causes Uveitis?Infections of all types can lead to uveitis: a virus infection such as Herpes zoster (the virus that causes chicken pox and shingles), a bacterial infection, a fungal infection such as histoplasmosis, or an infection by a parasite such as toxoplasma. When a definite infectious cause is identified, uveitis treatment is aimed at curbing the infection, as well as reducing the inflammation of the eye.
Non-infectious causes of uveitis include autoimmune diseases such as some types of rheumatoid arthritis. Recent or not-so-recent trauma to the eye can also lead to inflammation. Sometimes, the uveitis is described as idiopathic because there is no infection, but no definite cause can be found.
Types of UveitisThere are three types of uveitis depending on which part of the eye is affected. Posterior uveitis affects the blood supply to the retina, which is in the uveal layer at the back of the eye. Anterior uveitis mainly disturbs the tissues and structures at the front of the eye – the ciliary body and muscles that control the lens, and the iris. Intermediate uveitis affects the middle part of the eye and is the most common form.
What Symptoms does Uveitis Produce?As well as pain in the eye, which ranges from a dull ache to a sharp stabbing pain, your vision is also usually affected if you have uveitis. Blurring of vision is particularly common and you may also see ‘floaters’. You will probably be very sensitive to bright light and the white of your eye will look very red and sore. Severe uveitis may make you feel really quite ill, particularly if the cause is an infection, and you should seek treatment as soon as possible. Inflammation of the delicate tissues of the eye can lead to long-term vision loss.
Diagnosis of uveitis requires a thorough eye examination with a microscope with blood tests and X-rays to investigate the possible cause and the level of damage.
Getting Uveitis TreatmentThe first step that your treatment will take is to try to reduce the inflammation in the eye, whatever the cause. Eye drops are commonly used but, in severe cases your doctor or eye specialist will inject steroids directly into the eye. After the tests are complete and the cause of your uveitis has been established, if that is possible, you will also receive treatment for either the infection or the underlying condition that has set off the eye inflammation.
Different types of eye drops are used. One type contains steroids to damp down the inflammation generally but cannot be used if the cause of uveitis is a bacterial or viral infection. Using steroids may make the eye damage worse. Other eye drops containing drugs such as atropine are also used to keep your pupil dilated. The worst pain of uveitis occurs when the pupil constricts, as it does when you go from dull light to bright light. This can also cause the lens to stick to the pupil, which causes more pain. Keeping the pupil open allows the eye to heal more quickly and reduces pain. You may find you need to wear dark glasses though, as your sensitive to light will be more intense because your pupils are wide open all the time.
Some types of uveitis will also be treated with immunosuppressive drugs to damp down the body’s immune system generally.
Recovering from Uveitis
Once treatment is started, the uveitis usually starts to clear up within about a month, but some types will resolve more quickly. As with many problems with the eye, prompt treatment is always best.