WHAT EXACTLY IS A SQUINT AND HOW COMMON IS IT?
A Squint (or Strabismus) is a condition which arrises because of incorrect balance in the muscles that move the eye, faulty nerve signals to the muscles and some refractive error (focusing faults). If these are out of balance, the eye may turn in (converge), turn out (diverge) or sometimes turn up.
Approximately 5% to 8% of children are affected by a squint or a squint related condition, which means 1 or 2 in every group of 30 children. If your child appears to have a squint at any age from six weeks onwards, it is very important to seek professional advice quickly. Many children with squints have poor vision in the turned eye.
WHAT CAUSES A SQUINT?
There are several types of squint. The cause is not always known, but some children are more likely to develop it than other.
Some of the known causes include:
Sometimes a baby is born with a squint, although it may not be obvious for a few weeks. In about half of such cases there is a family history of squint or the need for spectacles. The muscles are usually at fault.
This can sometimes lead to a squint developing as the eyes are over-focusing whilst trying to see clearly. The over-focusing produces double vision. In an attempt to avoid this, the child may automatically respond by suppressing the image from one eye and turning it to avoid using it. If left untreated, a "lazy eye" may result. The most common age for this type of squint to start is between 10 months and 2 years of age, but it can occur up to the age of 5. It is usually first noticed when a baby is looking at a toy, or at a later age when a child is concentrating on close work, such as a jigsaw, or a book. (Click Here to learn more about long sight).
Following an illness such as measles or chickenpox, a squint may develop. This may mean that a tendency to squint has been present but, prior to the illness, the child was able to keep his or her eye straight. If after such an illness, you notice your child squinting, it may prove to be a good time to take him or her for a sight test, of course annual sight tests are strongly recommended for children in any case.
In some cases a difficult delivery of the baby or illness damaging a nerve can lead to a squint
ISN'T IT JUST A COSMETIC PROBLEM?
Certainly the appearance can lead to problems for the child, but a squint is NOT merely a cosmetic problem. If left untreated, it can lead to a permanent visual defect in the squinting eye, and as time goes on the squint can become more difficult to treat.
Untrained people usually think a child has a squint if their eyes look different. This is not necessarily the case. Squints are often difficult to detect, especially in young children. Older children may complain of double vision. If you think your child has a squint, ask your health visitor, Child Health Clinic, GP, School Doctor/Nurse about a referral to an optometrist, who may then refer you to the hospital eye clinic for further assessment.
It is normal practice in the UK for health checks for squints to be carried out during the child's first year and then again just prior to them starting school. It is also recommended that parents themselves carry out regular checks during the child's early years because the sooner the condition is diagnosed the higher the chances are of correcting the condition without recourse to surgery.
There are many forms of squint (oculomotor imbalances, triopias, amblyopia, eccentric fixation, and anomalous correspondence). the initial treatment for all of these conditions is usually the same.
In young children it is generally considered that squints are caused by muscle imbalances in the back of the eye. A common treatment is to put a patch over the dominant eye and force the lazy eye to look straight. The hope is that the imbalanced muscles in the back of the eye will strengthen, and when the patch is removed the eye will look straight.
WHY IS AN OPERATION SOMETIMES NECESSARY?
Sometimes an operation is the only way of straightening the eye sufficiently for sight to be retained in the squinting eye. As a child grows, the stronger eye becomes more and more dominant, and the parts of the brain that deal with vision decide to ignore all the information coming from the weaker eye.
If performed at the appropriate time results can be very good and satisfactory 3D vision can develop. There are occasions, however when the result may only be cosmetic, but the child's appearance in these cases is much improved. It is not unknown for more than one operation to be necessary. This does not necessarily mean something has gone wrong with the first operation, but sometimes some fine tuning is required to obtain the best results.
HOW IS THE OPERATION DONE?
The operation involves repositioning the relevant eye muscles, often in conjunction with shortening one of the other muscles. This has the effect of weakening or strengthening the muscles to get the best results.
WHAT HAPPENS AFTER THE OPERATION?
Your Child may be in hospital for about 48 hours and will usually be allowed home the day after the operation. Some hospitals treat squint surgery as a day case, in which case your child is likely to be very sleepy on the way home. The eye may be very red looking at first, which is perfectly normal and this will usually settle down within a few days. Your child should be able to return to school after ten days or so.
Regular follow up visits to the eye specialist will be necessary for progress to be monitored. It is very important that these appointments are kept.
If your child wore spectacles before the operation to correct long sight or short sight and/or astigmatism, spectacles will still be needed, at least to begin with. This is because the operation corrects muscle imbalances behind the eye, and not the muscle imbalances within the eye that cause focusing errors. As your child will be having regular follow-up care by the eye specialist and the orthoptist, tests to assess the need for spectacles will be carried out as part of this care.
Some children may not need spectacles as they get older, but this must be judged according to each individual child's needs. Your child may also experience some blurred for a few days after the operation; again this is perfectly normal, because the part of the brain that deals with vision will now be getting a different set of signals from the eye, and like any other operation there will be a small amount of swelling. Because the swelling occurs behind the eye this can also mean that the vision in that eye changes slightly as the swelling goes down. Some children, however will not notice any difference in their vision.
CAN ADULTS HAVE A SQUINT TREATED?
In certain cases it is possible to treat a squint in an adult, but it depends largely on the cause. Careful assessment will determine whether treatment is possible and may include surgery if appropriate.