What is uveitis?
The uvea is a name given to the pigmented layer of tissue inside the eye. When all or part of the uvea becomes inflamed, the condition is called uveitis. However, a more practical definition of uveitis is simply “any inflammation that affects the inside the eye”. It may affect all ages but is commoner in young and middle aged adults. Just like there are many different types of inflammations that affect the joints (“arthritis”), so too there are many different types of uveitis. Uveitis can be acute (starting suddenly and going away within weeks) or chronic (coming on gradually and lasting for several months or years). Acute forms of uveitis sometimes recur. Uveitis can affect one or both eyes, and if it affects both eyes, then this may be at the same time or at different times.
Main categories of uveitis
1) Anterior Uveitis (includes the terms “Iritis” or “Iridocyclitis”)
This is the most common type of uveitis. It affects mainly the front compartment of the eye. It is usually an “acute” condition that starts suddenly and lasts for a few weeks (“Acute Anterior Uveitis”). It causes a rapid onset painful red eye, usually on one side only, the pain characteristically being worsened by light. The eye may be watery. Acute anterior uveitis usually recurs (attacks of inflammation separated by inflammation-free periods) and may involve either eye at any one time. There are many other types of anterior uveitis, and separate information leaflets are available for these.
2) Intermediate Uveitis (includes the term “pars planitis”)
Intermediate uveitis mainly affects the large middle compartment of the eye – the “vitreous jelly”. It does not usually cause pain and redness. It usually affects both eyes, though often one eye is better than the other. In this condition, clumps of inflammation cells float in the vitreous jelly, which is normally clear. This can be seen by the affected person as “floaters” –dark spots of all shapes and sizes moving around. They are most obvious when looking against a light background such as the sky. With more severe inflammation, the jelly becomes cloudy, and the vision becomes misty. In most patients, the condition is chronic, lasting for months or years with a tendency to flare up without warning at times. A separate information leaflet is available for intermediate uveitis.
3) Posterior Uveitis (includes the terms “retinitis”, “choroiditis”, “chorioretinitis”, “retinal vasculitis”)
Posterior uveitis affects the back layers of the eye – the retina (the “photographic film” at the back of the eye: inflammation here is also known as “retinitis”), or the choroid (the layer underneath the retina that supplies oxygen and nourishment to the retina: inflammation here is also known as “choroiditis”), or both layers (“chorioretinitis”). Sometimes the inflammation mainly affects the blood vessels that nourish the retina (“retinal vasculitis”). Posterior uveitis is usually painless but causes visual deterioration in the form of blurring, patchiness or gaps in the vision, distortion of vision, flashing lights, loss of colour or night vision. If left untreated, posterior uveitis may cause permanent damage to vision. In many types of posterior uveitis, the condition is chronic, lasting for months or years with a tendency to flare up without warning at times. There are many different types of posterior uveitis, and separate information leaflets are available for certain specific conditions.
This term is used to describe uveitis that affects all the above three components of the eye equally. Most of the conditions in this category will be severe forms of posterior uveitis.
What cause uveitis?
Uveitis is an umbrella term covering many different diseases that have in common the presence of inflammation inside the eye. The exact cause in these diseases is often unknown, but in general there are two types:
1) In most patients uveitis is an “auto-immune disease”. The immune system is responsible for fighting infections, but in auto-immune diseases, the immune system mistakenly reacts against part of the body, causing inflammation and damage. In some types of uveitis, the inflammation is confined to the inside of the eye, but in other types it may be connected with inflammatory disease elsewhere in the body, which may or may not be apparent at the time the uveitis first develops.
2) In a small number of patients, uveitis can be caused by infections entering the eye and causing inflammation.
What tests might I need?
In the uveitis clinic, we spend time trying to determine your particular type of uveitis because this will guide its correct treatment, give an idea about how it may develop in the future, and establish any connection with disease elsewhere in the body. In order to do this, we need to talk to you about your eye problem and about your general health, conduct an eye examination under magnification using the “Slit-lamp”. In some patients, we may need to take pictures of your eyes. These may include dye-tests in which a dye is injected into the blood and photographs are taken of the back of the eyes. We may also need to take blood tests, X-rays or scans to help determine your type of uveitis.
Please note that your pupils will usually need to be dilated with eye drops for most examinations, photographs, and dye tests. This will blur your vision for a few hours, and you are therefore advised not to drive after your visit until your vision has recovered.
How is uveitis treated?
The treatment of uveitis varies depending on its severity and type. A few specific types of uveitis are caused by infections and need treatment with antibiotics, but most others are treated with steroids which reduce inflammation.
Anterior uveitis is usually treated with steroid eye drops. These are used quite frequently in the early stages, with a slowly reducing dose to prevent a recurrence.Patients with chronic anterior uveitis may need to use steroid drops for many months or years, usually at low doses. It is usually necessary to give eye drops to keep the pupil wide open (dilating drops) when anterior uveitis is severe. This reduces pain, prevents the pupil from becoming permanently small or odd-shaped, and helps prevent glaucoma. Dilating drops are inconvenient; they sting when put in and blur the vision, but they are essential to prevent permanent damage when uveitis is severe.
In intermediate and posterior uveitis, eye drops will not usually solve the problem, which is deeper inside the eye. If your problem is only affecting one eye or if it is more severe in one eye, you may be offered an injection of a steroid around your eye. You will receive local anaesthesia for this, so there should not be any pain. Injection treatments have the advantage of giving a treatment that is localised to the deeper parts of the eye and avoiding its side-effects on the rest of the body. If the injection fails or if the uveitis affects both eyes equally, you may be offered tablet treatment with steroids or other immunosuppressive drugs. Separate information sheets are available on these medications.
If another disease is discovered in your body, this will be discussed with you, your GP will be informed, and you may be referred to see a specialist in that condition.
Possible complications of uveitis
In most patients with anterior uveitis, permanent damage to the vision is unlikely to occur, particularly if the inflammation is mild, treated promptly, and treatment advice is followed correctly. However, the condition often recurs, and you should attend the Eye Emergency Department if you think this has happened. In intermediate and posterior uveitis, complications may be more common and more severe, especially if you do not follow treatment advice correctly or if you miss appointments.
Examples of complications of uveitis that may reduce the vision include:
- Cataract. This refers to lens inside the eye becoming cloudy.
- Glaucoma. This refers to high pressure inside the eye leading to damage to the main nerve at the back of the eye.
- Macular oedema. This refers to a fluid build-up on the central part of the retina (the macula), which is need for looking straight ahead or fine close work.
- Macular epiretinal membrane. This refers to a thickening and wrinkling of the macula that can result from uveitis and cause distortion of vision.
- Clouding of the vitreous jelly.
- Scarring on the retina.
- Closure of blood vessels of the retina.
- Retinal detachment.
The aim of treatment in uveitis is to reduce the inflammation and therefore minimise its harmful effects on vision, and to deal with any complications if needed. Separate information leaflets are available on Cataract, Glaucoma, and Macular Oedema in Uveitis.
Is there anything I can do to help myself?
- Follow the treatment advice correctly.
- If your medications run-out and you are supposed to continue treatment, you must obtain further supply.
- Attend for your review appointments. If you are not able to attend then contact the department and re-schedule the appointment.
- Return to the hospital promptly if you feel there is a flare up of your uveitis.
- Sunglasses during a flare up of acute uveitis may help reduce light sensitivity.
Uveitis is an extremely variable condition. Every patient and every eye inflammation is different. The information above is intended only to give you a general picture of uveitis. Always ask the doctors and nurses in the clinic if you are unsure of, or want more detail on, any points in relation to your own eye problem and general health. There are several other information leaflets available in the uveitis clinic which may be useful to you. Please ask.