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 Why do we need to screen?
It is known that children with Juvenile Idiopathic Arthritis (JIA) are at risk of developing a particular type of
inflammation within the eye known as iritis. We cannot say exactly why this is, but we do know that it is very
important to discover this condition promptly, as if left untreated, it can potentially cause damage to the eyes.
It is important to examine all children with JIA as the majority of children
who develop iritis will not initially notice any redness, discomfort or blurred vision as a result of the condition.
Without an examination by an ophthalmologist to exclude iritis, it can be present for many months or years causing
damage to the eye without the child or the parent noticing anything untoward.
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Regular eye examinations or screening are therefore an essential part of the care of a child with
JIA, in order that problems within the eye can be detected early and appropriate treatment begun. In this way, any potential
harm to the child’s vision can be minimised.
What is iritis?
Behind the clear window (or cornea) of the eye, and separated from it by a thin layer of fluid is the iris.
This is the structure which contracts and expands in different lighting conditions and gives the colour to our
eyes. Behind the iris is a small clear lens rather like the lens in a
camera. The lens assists in the focusing of the eye and has the ability to alter its focusing ‘power’ so allowing us
to see things clearly both in the distance and close up.
In iritis, the iris itself becomes inflamed and although to the naked eye it still looks normal, this inflammation is
visible with a microscope called a slit lamp.
What problems can iritis cause?
Persistent iritis can potentially cause serious harm to a child’s vision. The inflamed iris can stick to the
lens behind it, causing an odd shaped pupil and interfering with its ability to react to light and very occasionally
causing the pressure within the eye to rise (glaucoma).
The lens itself can also be affected by the persistent inflammation. In a normal eye, the lens is entirely
clear, but the inflammation may make the lens become opaque and then a cataract is said to have formed.
Prolonged iritis can also affect the cornea. A deposit of calcium can build up within the normally clear
structure which can often be seen with the naked eye as it looks white. Usually the deposit remains small but
occasionally it too can obstruct vision and require removal by surgery or laser.
The optic nerve is located at the back of the eye and delivers the images seen by the eyes to the brain.
Rarely, if the pressure in the eye is high (glaucoma) the optic nerve becomes damaged. The retina is the film at
the back of the eye. A rare complication of prolonged iritis is retinal detachment when this film tears. This is
most likely to occur in children who have had an operation to remove cataracts.
When do we need to screen?
The risk of developing iritis varies according to the type of Juvenile Arthritis. Generally, a child who is very
severely affected by arthritis will be less likely to develop iritis and
a child with only mild joint disease will be at greater risk. These are only general rules however, and when planning
how frequently to review a child we also rely on a number of immunological blood tests.
Visits to the ophthalmologists are necessary all the time your child is under surveillance by the
rheumatologist. The necessary interval between visits will therefore vary between children, usually ranging from
3 months to 1 year.
Every effort is made to make the child comfortable and at
ease during the examination. Most children, especially after their first visit, are very happy to be examined and
co-operate fully with all the necessary tests.
Firstly, we will measure the child’s vision either by reading letters from a chart, or by recognising pictures
for younger children. It is important that children with glasses should wear them for these tests and they should
therefore be brought to every clinic visit.
Following this we will examine the child’s eyes on a microscope (slit lamp) for the signs of iritis. Only a
fairly brief look at each eye is required but the parent’s assistance is often needed to encourage the child to
remain still. We may also need to assess the pressure within the eye for which we will need to-put a-drop into
each eye.
Finally, it may be necessary to examine the back of the eye. This often requires drops to dilate the iris in
order to get a better view. Children may report slightly blurred vision as a result of these drops. This will always
clear however, usually taking between 1 and 3 days depending on the type of drops used.
Occasionally during the examination we may discover other unrelated eye conditions such as allergic
conjunctivitis or squint. Appropriate advice or treatment will be given if this occurs.
Treating iritis.
If iritis is discovered in either
eye, treatment in the form of drops will be necessary. The first aim of treatment is
to control the inflammation, this being achieved with steroids.
Various strengths of steroid drops are available but Dexamethasone (Maxidex) or Pred Forte are the most
common. The number of applications per day will depend on the degree of inflammation and can vary from
hourly in a recently discovered severe iritis to once every.other day or even weekly in very mild inflammation.
A second treatment commonly used is a drop to dilate the pupil. This is important to prevent the inflamed
iris sticking to the lens behind it, and causing the problems that have previously been described.
Tropicamide (Mydriacyl) and Cyclopentolate (Mydrilate) are commonly used in this way, being given either twice a
day or once at night.
Finally, it may be necessary to give a drop to control pressure within the eye, if it is raised as a result of the
inflammation. Timolol is a commonly used formulation and is given twice a day.
What are the side effects of treatment?
Drops which dilate the pupil and treat pressure are associated with very few problems. Steroid drops
however, can have significant side effects and for this reason they are rarely given unless under constant expert
supervision.
Steroid drops can cause the pressure to rise within the eye or they may accelerate the formation of a
cataract. However, the likelihood of this happening is greater if the inflammation is left untreated. All children
taking these drops are therefore reviewed at safe intervals to guard against the development of these problems.
The majority of children in whom we find iritis will respond
promptly to treatment. The level of inflammation will decrease and after a variable period we will be able to
taper down the treatments or stop them all together. During this time, we will review the child frequently to
monitor the effectiveness of treatment and carry out any necessary adjustments.
When the inflammation has subsided, we will of course continue to review the child at appropriate intervals
as it can often recur requiring a further course of treatment.
In some cases, if you are travelling a considerable distance and very frequent visits are required, it may be
possible to arrange shared care with your local ophthalmologist.
In a minority of children, iritis can be very severe or respond poorly to appropriate treatment. Very rarely,
despite every effort to control the disease, the inflammatory process continues, resulting in a raised pressure
within the eye, calcium deposition on the cornea or cataract. Cataract surgery however often offers the
prospect of improved vision in this situation and is frequently carried out.
We find that the vast majority (85%) of children with iritis maintain good vision. With the benefit of the
screening programme, the inflammation can be detected early and appropriately treated. Although frequent
clinic visits and persistence with the treatment may often be required, the hard work involved is fully rewarded
by the long term benefits for the child.
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The Eye and
JIA written by Dr Elizabeth Graham, Consultant Medical Ophthalmologist,
St Thomas’ and Great Ormond Street Hospitals, London, and Dr John Greenwood. |
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