– What are the different types of uveitis?
– What causes uveitis?
– Anterior uveitis (iritis)
– Intermediate and posterior uveitis
– What are the complications of uveitis?
What are the different types of uveitis?
Your eyeball has three layers, the outer tough coating which is the white of the eye, the innermost light-sensitive layer called the retina and a middle layer called the uvea. Your uvea is made up of your:
- Iris – the coloured part of the eye which controls the amount of light entering your eye.
- Ciliary body – the circular band of tissue behind the iris which produces the internal fluid of the eye.
- Choroid – a layer of pigmented tissue and blood vessels which supply your retina. Your retina can also be affected in uveitis.
Uveitis is described in different ways depending which part of your uvea is affected:
- Anterior uveitis is when the iris or ciliary body at the front of your eye is affected (sometimes called iritis).
- Intermediate uveitis is when the area behind your ciliary body is affected, with most of the inflammation being seen in the vitreous, the jelly-like substance that fills your eye.
- Posterior uveitis affects the choroid (choroiditis) or retina (retinitis) or both. It can also affect the optic nerve head, where the nerve fibres leave your eye for the brain. There are many types of posterior uveitis including Birdshot chorioretinopathy or punctate inner choroidopathy (PIC).
- Panuveitis is where the inflammation affects the whole uvea.
Uveitis may also be described depending on how long it lasts:
- Acute: when your uveitis starts suddenly but improves within three months.
- Recurrent: when the inflammation flares up and settles down over months and years. Anterior uveitis is usually recurrent with acute episodes.
- Chronic: when the inflammation is longer lasting and also comes back within three months of stopping treatment. Intermediate and posterior types of uveitis are usually chronic.
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What causes uveitis?
There are a number of different causes for uveitis, these include:
Auto-immune and inflammatory conditions
Uveitis may develop in people who have an underlying auto-immune condition (where the immune system mistakenly attacks healthy tissue).
Often in uveitis, the inflammation only affects the inside of your eye, but sometimes it may be connected with an inflammatory condition elsewhere in your body. You may or may not know that you have another inflammatory condition at the time the uveitis first develops.
About 50 per cent of people with anterior uveitis have a gene called HLA-B27. This gene is found in people with certain auto-immune conditions including:
- ankylosing spondylitis
- ulcerative colitis
- psoriatic arthritis
- Crohn’s disease
- reactive arthritis (formerly known as Reiter's syndrome).
People with one of these conditions have an increased chance of developing anterior uveitis.
Other inflammatory conditions are also more prone to developing uveitis:
- chronic anterior uveitis in children may be associated with juvenile arthritis
- intermediate uveitis can be associated with sarcoidosis or multiple sclerosis
- posterior uveitis can be associated with Behcet’s disease or sarcoidosis.
Uveitis can be caused by viral, bacterial or parasitic infections. Examples can include:
- virus – herpes simplex (cold sores), herpes zoster (chickenpox and shingles), or cytomegalovirus
- bacteria – tuberculosis or syphilis
- parasites – toxoplasmosis.
Many of these infections which cause uveitis are more likely in patients with poorly active or suppressed immune systems. This includes patients who have had organ transplants, leukaemia or HIV and AIDS.
An injury to your eye can cause uveitis in that eye. A very severe injury can even trigger the immune system to cause uveitis in the other eye, known as sympathetic ophthalmia. This is very rare and only an injury through the eyeball wall, needing an operation to repair, can lead to sympathetic ophthalmitis.
Sometimes it may not be possible to work out what the cause of your uveitis is. This is called "idiopathic" and means that it is not clear what the cause is, and that no other cause can be found. It’s thought that most of these cases may be autoimmune but this cannot be confirmed.
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Anterior uveitis (iritis)
The most common type of uveitis is anterior uveitis.
What are the symptoms of anterior uveitis?
The symptoms of anterior uveitis usually start over hours or days and usually only affect one eye at a time. It typically causes eye pain, eye redness and sensitivity to light (photophobia). The eye pain is often aching and the eyeball feels tender. Vision may be slightly blurred.
When symptoms like this occur, it’s important to have your eyes checked straight away either by the optician or by the hospital.
How is anterior uveitis diagnosed?
Anterior uveitis is usually diagnosed by an ophthalmologist (eye specialist) using a piece of equipment called a slit-lamp, which consists of a microscope and a powerful bright beam of light. It allows them to check for signs of inflammation.
What is the treatment for anterior uveitis?
For most people with anterior uveitis a course of eye drops is all the treatment needed to clear up the inflammation.
Steroid eye drops
Corticosteroid eye drops are used to reduce the inflammation at the front of the eye.
Depending on the level of inflammation, the dose can range from using the eye drops every hour to using them just once a day. As the inflammation gets better, the dose will be reduced slowly by your ophthalmologist. It’s important to not stop using your eye drops until your ophthalmologist advises you that it is safe to do so, even if your symptoms disappear, as stopping your treatment too soon can cause the inflammation to return.
Using steroid eye drops in the short term doesn’t normally cause many side effects. While you’re on steroid drops your resistance to eye infections will be reduced. Since wearing contact lenses may encourage infection, you’re usually advised against wearing these during your treatment.
If steroid eye drops are used for long periods of time, they can lead to raised eye pressure (glaucoma). High doses for long periods of time can lead to clouding of the lens (cataract), particularly in children. If your uveitis is treated for a number of months then your ophthalmologist will monitor your eye for these complications.
Cycloplegic or mydriatic eye drops
Cycloplegic or mydriatic eye drops are given for anterior uveitis in addition to steroid medication.
These drops relieve the pain by paralysing the muscles of your iris and ciliary body as it is the movement of these inflamed muscles that cause the pain.
The drops also dilate your pupils and are used to reduce the risk of your iris sticking to your lens (known as synechiae). A synechiae can lead to raised pressure in your eye and cause glaucoma.
These drops can cause some temporary blurring of your vision and problems focusing. You may also become more sensitive to the light as they make your pupil larger. Wearing dark sunglasses can make your eyes feel more comfortable and help with problems of glare during this period. Once you stop taking these drops your pupil should react normally to light.
If your uveitis is caused by an infection, the infection will need to be treated with antiviral or antibiotic eye drops too.
What happens in the long term with anterior uveitis?
An episode of acute anterior uveitis which has been treated promptly doesn’t usually cause any long term changes to your sight. This is because it responds quickly to treatment so only a short course of eye drops is needed and most people recover within a few weeks.
Some people will only ever have a single episode of anterior uveitis. However, it can recur or become chronic in which case it may cause more problems over time.
Some people who have recurrent uveitis learn to recognise their symptoms. Unfortunately there is little you can do to prevent recurrences in either eye. The best thing is to recognise that it can recur and so get the inflammation treated as quickly as possible to prevent complications.
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Intermediate and posterior uveitis
Intermediate uveitis is most commonly seen in young adults. Posterior uveitis is the least common form of uveitis.
What are the symptoms of intermediate and posterior uveitis?
Intermediate uveitis can cause floaters (shapes, dots and wispy lines that move across your vision). It usually affects both of your eyes. Your vision may gradually feel more blurry and occasionally you may be sensitive to light. Some people with intermediate uveitis may also get anterior uveitis.
Posterior uveitis causes blurry, distorted vision or patchiness or gaps in your vision. It can also cause problems with colour or night vision.
Intermediate or posterior uveitis doesn’t usually cause any eye pain or redness. They’re usually more chronic, lasting months or years, with a tendency to flare up at times. Both eyes are usually affected but not always at the same time or to the same degree. The condition may be present for quite some time before it is diagnosed because you may not be aware of any problem.
How are intermediate and posterior uveitis diagnosed?
There’s a wide range of causes of uveitis and many medical conditions can be associated with it. Your eye examination shows which part of your eye is inflamed but doesn’t show what has caused the inflammation. Your ophthalmologist may want to do further tests to identify the cause, which may include blood tests or X-rays of your chest.
Although these extra tests may not seem connected to your eye problem, they’re important in finding out the cause of your uveitis. This will help plan the correct treatment for you, give you an idea about how it may develop, and find any connection with a condition elsewhere in the body. If another condition is discovered you may be referred to see a specialist in that condition.
Some more specialist eye tests you may have can include:
- Fluorescein angiography. This is a way of looking at the circulation of your retinal blood vessels and find out how much of your retina is being affected by the inflammation. A yellow dye is injected into your arm, which travels through the bloodstream to your eye which allows the ophthalmologist to check for any circulation problems.
- Indocyanine green angiography (ICG) is a similar test to fluorescein angiography but a different type of dye is used.
- Optical coherence tomography (OCT) scans your retina to check for swelling and inflammation.
- Electroretinogram (ERG) is a test to check how well the light- sensitive cells of your retina are working.
- If an infection in your eye is suspected as a cause for your uveitis, the ophthalmologist may take a sample of fluid from inside your eye to look for this. This can be done with local anaesthetic eye drops in the eye clinic.
Specific types of posterior uveitis
Birdshot chorioretinopathy is a type of chronic posterior uveitis, which can last a long time and the inflammation can often flare up and down. It’s thought to be an autoimmune condition which affects the eyes only.
The onset of the condition is usually gradual and in the initial stages, you may be able to continue to see well but may have problems with night vision and colour vision, and be sensitive to bright lights.
How Birdshot chorioretinopathy affects vision in the long term can be very varied. People with milder forms of Birdshot can often maintain good sight with little or no treatment. However, more severe cases can be difficult to treat and cause complications which can lead to changes in your sight.
The Birdshot Uveitis Society can offer more information about this specific type of uveitis and can also provide support to those affected.
Punctate inner choroidopathy
Punctate inner choroidopathy (PIC) is a rare form of posterior uveitis which tends to affect mainly women who are short-sighted, but why people develop PIC is not fully understood.
Symptoms can include blurred vision, "blind spots" in your vision and seeing flashing lights.
Often, the inflammation in PIC can resolve on its own and it doesn’t always require treatment. However treatment is given if there are many active or central areas of inflammation.
People with PIC and some other forms of posterior uveitis can develop a complication where there is growth of new vessels in the choroid (choroidal neovascularisation). These new vessels are weak and leaky which causes swelling and bleeding of the retina and can lead to scarring and sight loss. Treatment will usually be aimed at controlling the inflammation as well as treating any new blood vessel growth.
What are the treatments for intermediate and posterior uveitis?
Treatment for uveitis can differ from person to person quite considerably and will also take into account the cause of your uveitis.
Apart from certain types of uveitis caused by infection, steroid medication (corticosteroids) is the mainstay of treating uveitis. Corticosteroids work by reducing the activity of your immune system so that it no longer releases the chemicals which cause inflammation.
Injections or implants
Injections are used for intermediate or posterior uveitis to deliver the steroid to the parts of the eye that are inflamed. Steroids can be injected into the eye either as a liquid or small implant to treat non-infectious uveitis.
The injections and implants are usually given if only one eye requires treatment and can be given around the eye or into the eye. An injection given to your eye may be a scary thought, but most people experience only mild discomfort because local anaesthetic eye drops are used to numb the eye beforehand.
An implant which is like a thin grain of rice can be injected inside your eye. The steroid medication is released slowly from this implant and lasts between 3-6 months.
Tablet corticosteroids are usually given if injections or implants haven’t been successful in controlling the inflammation, or if the uveitis is affecting more posterior parts of your eye.
How long you’ll need to take tablet corticosteroids will depend on how well your uveitis responds to treatment and whether you have an underlying autoimmune condition. Some people may only need a three to six-week course, while others need to have a course lasting months or possibly years.
Oral corticosteroids work well in relieving inflammation, but can cause side effects. These can include weight gain, mood changes (feeling irritable or anxious), osteoporosis (fragile bones), stomach ulcers or diabetes. Most of these side effects will be monitored, using blood or urine tests, measuring blood pressure and weight etc, but if you are concerned about any side effects, you should ask your GP. You may require additional medications to prevent stomach ulcers or osteoporosis.
Although steroids can cause side effects, the threat to sight in the long term is worse if uveitis is not treated properly. Your ophthalmologist will usually start with a higher dose and once the inflammation is controlled bring the dose down to a level with fewer side effects but enough to keep the inflammation settled.
It’s important to not stop taking your medication suddenly. If your ophthalmologist decides you no longer need treatment, they’ll reduce the dose of your medication gradually.
Immunosuppressant medication may be recommended if uveitis doesn’t respond to other treatments or to allow the dose of steroids to be reduced if they are causing you significant side effects. In some types of uveitis, the systemic condition needs to be treated with this medication as much as the eyes do.
Taking immunosuppressant drugs will make you more vulnerable to infections, so you should avoid close contact with anyone who has a known infection. You should also report any symptom of a potential infection, such as high temperature or cough, to your doctor. If you attend any health centre, either as an emergency or for a routine procedure or operation, you should tell the doctors or nurses looking after you that you are taking immunosuppressants.
If your uveitis is caused by an infection, the infection will need to be treated with antiviral or antibiotic tablets too.
In rare cases, surgery may be needed to treat uveitis. However, this is usually only used if you have repeated or severe uveitis that affects the back of your eye.
An operation called a vitrectomy to remove the vitreous (jelly that fills the eye) may be used. This jelly will be removed and temporarily replaced during the operation with either a bubble of gas or a liquid substitute. Eventually, your eye will naturally replace the vitreous with a slightly different clear fluid called aqueous humour.
If your uveitis isn’t responding to treatment or your ophthalmologist suspects that there is something else behind the uveitis, they may want to get a sample of the vitreous to test for infection or tumours.
Other possible treatments for non-infectious uveitis affecting the back of the eye include anti-TNF drugs. Anti-TNF drugs belong to a group of medications called biologics.
TNF (tumour necrosis factor) is a protein produced in the body that causes inflammation. Anti-TNF drugs block the action of TNF and so can reduce this inflammation.
Treatment with anti-TNF medication may be given to people where treatments with corticosteroids or immunosuppressants haven’t worked, or are making their use difficult, and the uveitis is causing worsening of their vision. The type of anti-TNF drug used for uveitis is given as an injection under your skin, usually in your tummy or thigh.
Biologics are also used for the treatment of other inflammatory conditions, including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, ulcerative colitis or Crohn’s disease.
What happens in the long term with intermediate and posterior uveitis?
The way in which your sight may be affected in the long term by intermediate/posterior uveitis may be due to the direct effects of the uveitis or its complications.
Uveitis affecting the back of your eye tends to heal more slowly so more prolonged treatment is likely to be necessary. The time for a response to treatment, how long a flare-up lasts and how vision is affected in the short and long term really varies from person to person.
If you have chronic or recurrent uveitis, you will usually be under the long-term care of an ophthalmologist and will have regular checkups in the outpatient clinic.
Certain types of uveitis are uncommon and require specialist care. You may therefore be referred by your local ophthalmologist to a specialist eye department and need to travel further for our appointments. This is necessary in order to have the specialist care and treatment, however once the uveitis is controlled you may be able to be referred back to your local eye department.
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What are the complications of uveitis?
Uveitis needs to be treated promptly to try to reduce the risk of further problems that might affect your sight. Good control of inflammation can be achieved in most people and this reduces the risk of developing complications. The treatments that are used for uveitis can have side effects (and may need monitoring), but controlling the uveitis properly with treatments will generally give a better outcome for your sight than "under-treating" and allowing the uveitis to continue.
Some of the complications uveitis can cause include:
Raised eye pressure
Untreated anterior uveitis can slow down the drainage of fluid within the eye causing the pressure in the eye to rise. If not detected, monitored or treated this raised pressure causes damage to your optic nerve (made up of nerve cells carrying light signals to the brain), resulting in glaucoma. Your ophthalmologist will check your eye pressure when you attend the eye clinic.
Untreated anterior uveitis can also cause parts of the iris to stick to the front surface of the lens (known as posterior synechiae). If this progresses to involve the whole iris it prevents fluid draining through the pupil and increases your eye pressure. This can cause your vision to be misty and halos to appear around lights.
Cycloplegic or mydriatic eye drops which cause the pupils to dilate are given to people with anterior uveitis to help to prevent a synechiae.
Using steroids can also cause an increase in eye pressure for some people. At least five per cent of the population are “steroid eye pressure responders”, meaning that the eye pressure goes up when steroids are used. Your ophthalmologist will determine whether you fall into this group and may prescribe eye drops to lower your eye pressure.
Macula oedema can affect some people with chronic uveitis or uveitis that affects the back of the eye.
Prolonged inflammation can result in a build up of fluid inside the central part of the retina (the macula). This can affect your central vision and you may notice blurriness, distortion, or a black spot in the central part of your vision.
Macula oedema can be treated using corticosteroid injections or tablets. In most cases, vision can improve with treatment particularly if it’s treated early. However, this isn’t always the case in severe or prolonged cases of macula oedema, and it’s one of the main causes of sight loss in people with uveitis.
Your central vision can be affected by macula oedema and can cause difficulty in recognising faces, reading and watching television. Straight lines may appear wavy or distorted. Detecting movement in your side vision is not affected with macula oedema so getting around is generally not a problem.
The inflammation inside the eye can sometimes cause cloudiness of the lens. This cloudiness is called a cataract and can cause symptoms such as blurred or misty vision, colours appearing dull, or problems seeing clearly at night.
Cataracts can also be caused by long term steroid treatment (over years), but this has much less of an effect on sight than under-treating the uveitis would.
Cataracts can be treated using surgery to remove the affected lens and replace it with an artificial one.
Floaters are seen as black dots or wispy lines floating across your vision as a result of clumps or cells in the vitreous. General haziness can occur if there is active inflammation and inflammatory cells in the vitreous or anterior chamber. Light sensitivity can make bright light uncomfortable. Using sunglasses, tinted lenses and sunshields can help to reduce the discomfort and glare you may experience in everyday living.
In posterior uveitis, the inflammation can cause fluid to collect under your retina so that it comes away or is detached from the back of the eye. Alternatively the inflammation can cause pulling on the retina or a hole to develop in the retina leading to retinal detachment. This is uncommon and tends to occur in specific types of posterior uveitis including certain infections.
Retinal detachment can cause you to experience flashing lights in your vision, or a shadow in the corner of your vision which does not go away and may progress to come across your vision.
It’s important to seek attention that day if you suspect having a retinal detachment as if left untreated can cause permanent loss of sight.
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It’s completely natural to be upset when you have been diagnosed with uveitis and it’s normal to find yourself worrying about the future and how you will manage with a change in your vision. We’re here to support you every step of the way, and to answer any questions you may have – just get in touch with our Sight Loss Advice Service.
Can I get help to see things better?
In whatever way the uveitis has affected your sight, there are lots of things you can do to make the most of your vision.
If uveitis has affected your sight then ask your ophthalmologist, optometrist or GP about low vision aids, like a magnifier, and ask for a referral to your local low vision service. You should also ask whether you are eligible to register as sight impaired (partially sighted) or severely sight impaired (blind). Registration can act as your passport to expert help and sometimes to financial concessions. Even if you aren’t registered a lot of this support is still available to you.
Local social services should also be able to offer you information on staying safe in your home and getting out and about safely. They should also be able to offer you some practical mobility training to give you more confidence when you are out.
Our Sight Loss Advice Service can also give you practical guidance on living with sight loss, and our Online Shop has products that can make everyday tasks easier.
Other useful contacts
- Uveitis Information Group is a charity run by volunteers who are affected by uveitis and can provide information and support.
- Olivia’s Vision can provide information, advice and support to anyone affected by uveitis. They can also help you connect with others in the same position.
- Birdshot Uveitis Society is a charity providing support and information for people with a type of uveitis called Birdshot chorioretinopathy.
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