EYES THAT ARE LAZY AND EYES THAT TURN
A lazy eye has poor vision (despite wearing the best possible glasses) because the best potential vision did not develop. This is also called Amblyopia. A lazy (amblyopic) eye often also has poor focusing but fixing the focusing (by giving glasses) isn't enough to make the vision normal.
A 'turned' eye(s) is an eye that is not pointing in the right direction (misaligned or strabismus).
LAZY eyes and TURNED eyes often "go together". If an eye is turned, then about 50% of the time it is or will go lazy. If an eye is lazy, then about 30% of the time it has or will develop a turn. SO, a lazy eye is more likely to turn, and a turned eye is more likely to be or to become lazy.
If an eye has poor vision that is fixed with glasses, this eye is not lazy (does not have amblyopia); this eye has poor focusing without amblyopia. If the poor vision is partly fixed by the correct glasses, the eye has both amblyopia and poor focusing.
Fixing strabismus and amblyopia when the child is very young helps proper development of vision. There is a "window of opportunity" when fixing strabismus is more likely to give best results, and in most cases this is within a few months of the eyes first becoming constantly turned. Fixing amblyopia should be commenced as soon as it is recognised - it is more difficult to fix amblyopia in children older than 6 or 7 years.
Why does an eye turn?
There is usually a combination of:
a. Amblyopia (lazy eye)
b. Pre-existing muscle control problem - either no "high quality" brain wiring for eye muscle control or a muscle balance problem (anatomy problem).
c. Focusing problem.
d. Abnormalities in muscle length and tension
Commonly the focusing "problem" that is part of a turn is mild and would not have caused a turn if all else was OK. Mildly abnormal focusing only becomes an important factor because the other associated problems weaken the whole system. The focusing part of things is the only factor that is easy to fix (glasses).
Treatment of a lazy or turned eye often requires glasses. Be as strict as possible in ensuring the child wears the glasses ALL the time. You should buy your child's glasses from a shop that has access to a LARGE RANGE of children's frames and has staff that are interested in helping you
Glasses prescriptions are checked at least twice a year and typically need to be changed at least once a year.
If your child needs thick glasses be prepared for "helpful" comments from others. Have a few responses ready "he's been reading since he was born", "she starts high school next week", "he sees better than I do", etc.
Sometimes glasses alone are enough to fix a turn and a lazy eye but usually extra treatment is required. This often involves occluding or blurring the better eye to make the amblyopic eye "work harder".
Techniques used to do this include:
(a) wearing a patch over the good eye ("Opticlude" stuck onto the
skin around the eye), or
(b) atropine drops in the better eye to blur near vision.
(c) Patchmate, a material patch slips around the arm of your chil's glasses.It can be purchased on the internet- www.patchmate.com.au
For severe amblyopia I recommend patching for more than 50% of waking hours every day for at least five days a week. For mild amblyopia, two hours a day of patching is probably enough, or weekend Atropine drops can be used. Sometimes the effect of Atropine can be augmented by temporarily changing one spectacle lens.
Amblyopia treatment is like going on a diet. Sticking to the diet works, cheating doesn't, and the weight can come back when the treatment is stopped.
During treatment, a turn may change. For example: instead of one eye turning all the time, we may get either eye turning (usually a GOOD thing).
Once the best result has been achieved, and this can take some months, we taper off the treatment to the minimum required to maintain the new result. Around the age of 7 or 8 this occlusion treatment can be stopped altogether though glasses may still be required if there is a focusing problem.
Yearly check-ups must be arranged until age 10 to ensure that a good result does not "slip". Your local Optometrist can do these check-ups. Slippage can happen even after 2-3 years of stability!
Children who are difficult to patch
Many children will not like a patch when it is first put on. Sometimes this is because children will not like anything stuck on their face - try putting the patch on the forehead and the result will be the same! Persist and in 15-20 minutes things may be easier. The first day often has some "novelty" value. The second day may be much more difficult. Babies can be put into mittens for a few hours to stop them from pulling off the patch.
Some children will simply not tolerate a patch at all. Sometimes this is because the vision in the bad eye is too bad to function well. In these cases, other techniques can sometimes be used.
Patches for amblyopia treatment
The only ones regularly available in Australia are Opticlude. These are skin coloured and come in two sizes. They are effective. Adhesive irritation or allergy is an uncommon problem.
We have a small supply of nicer looking Italian ones with a different adhesive. Device Technologies also sell these (Ortopad and Ortopad fun pack).Call 1800 804 006 to order these.
The importance of appearance
One important reason for treatment is to make your child's appearance normal. Facial interaction as an infant is important in developing a normal relationship between a child and the siblings, parents and other relatives. If the child does not look normal, there may be some discomfort in looking at the child and this enters into the interaction. When older and socialising, children who don't look normal typically attract adverse reactions from other children, usually from age 5 and a half. This can affect the child's self-esteem.
Once the best result has been achieved with glasses and patching, attention is then given to any turn that remains. If a misalignment is easily noticed then we consider an operation. Experts (like mothers or Dr Kowal) are not always the best judge of whether a misalignment is easily noticed. Ask non-experts (grandparents, kindergarten staff) for their opinion also.
Surgery changes the muscles that have abnormal length and/or tension or anatomy and tries to take account of problems in the brain's muscle computer. We cannot operate to readjust the computer; we can only operate on the muscles (the "guy ropes" that move the eyes).
In general, surgery is effective 80+% of the time. This means that if accurate measurements are obtained and accurate surgery is performed, 80+% of the time healing takes place normally and the visual system optimally adjusts to the new situation. When the eyes are surgically straightened, if "high quality" brain wiring is present then the eyes are likely to stay straight forever. If "high quality" wiring is not available then long term results are less satisfactory. The quality of "wiring" is usually apparent some weeks or months after the surgery.
In most cases surgery can be done as a "day case". The patient comes into hospital early in the morning, the surgery is done in the morning, and if all goes well can go home a few hours later. The patient is usually seen again the next morning.
With the commonest operation performed on children by Dr. Kowal, the bimedial recession, a recent audit has given the following results:
Perfect : 75% (zero deviation at least some of the time).
Near-perfect : 5% (misalignment < 5 degrees).
Re-operation within 12 months : 11%
How Safe Is Surgery?
Serious complications from strabismus surgery are very rare but can include:
1. Anaesthetic complications.
Modern anaesthesia is considered to be very safe. Giving an anaesthetic to an otherwise healthy person has a serious complication rate of about 1 in 120,000 to 200,000 anaesthetics.
2. Damage to the vision. From American experience we know that 1 in 35,000 operations has a serious vision threatening complication (retinal damage or infection), and that about 1/2 of these patients end up losing some or all of the vision in the operated eye.
To put these numbers into perspective, the risk of dying in a car accident in Victoria this year is 1 in 10,000. So, being a driver or passenger in a car in Victoria or even a pedestrian seems to be several times more dangerous than having a strabismus operation.
What Is A Good Result?
A good result is achieved in most cases when:
a. There is good vision in both eyes.
b. The vision is near equal.
c. The eye alignment looks normal.
c. There is a low expectation of needing further surgery.
This is achieved 80+% of the time.
A fantastic result is achieved in a smaller number of cases when there is:
a. Good or equal vision in both eyes.
b. There is normal appearance of eye alignment.
c. High quality depth perception is achieved on testing.
d. One anticipates long term stability and
e. There is a very low expectation of needing further surgery.
Dr. Kowal specialises in strabismus, the treatment of turned eyes, and does nothing else.
A copy of his C.V. is available for you to peruse.
For those of you who are on the internet, a highly recommended site for you to look at is our own website www.netspace.net.au/~strabism/ with U.S. links. Another website you may wish to visit is: www.egroups.com/group/LazyEye where you will find parents who are going through what you are going through.