And post-operative care

Strabismus surgery

The surgery involves altering the position of the eye muscles in order to change the position of the eye. It is most frequently performed for an in-turning or out-turning eye but may be used for vertical or rotational imbalances as well.

Eye muscles can be:

1. Weakened - This usually involves recessing the eye muscle or moving it posteriorly on the eye to elongate the muscle and allow the muscle tissue to relax more.

2. Tightened - Muscles are tightened by resection, which involves removing a piece of the muscle near where it inserts into the eye and then reinserting the muscle into its original location. By removing a piece of muscle the muscle is shortened and therefore strengthened.

3. Repositioned - for some strabismus problems the eye muscles are neither weakened nor strengthened but repositioned: ie, the insertion is moved to a different location to provide a different action on the eye.

The operation

Eye muscle surgery is usually performed under general anaethesia, although in some circumstances it can be performed under local anaesthesia. It is a day case procedure so no overnight stay in hospital is required.

Eye muscle surgery is frequently performed on both eyes at once. Even if it tends to be one eye that turns in or out more often than the other, it is often still advisable to split the surgery between the two eyes. The aim of surgery is to achieve good alignment of the eyes and this can be obtained by doing a lot of surgery on one eye or less on two eyes. Often the latter is preferable.

At the end of the operation local anaesthesia is injected around the eyes to try to have the eye numb when you wake up. This anaesthetic wears off over a few hours. It is fine to take paracetamol or other pain killers but you probably won't need them beyond the first day.

Post-operative care

After surgery you will be required to use eye drops for a week and then you will be reviewed. If the eye is settling nicely then the eye drops will be discontinued at that stage. A further post-operative appointment will be made for six or eight weeks later, by which time the result of the surgery will have stabilised.

After surgery, the eyes are usually a little red and watery. There may be some haemorrhage under the conjunctival membrane over the white of the eye which will settle over two to three weeks. It usually takes on a yellowish discolouration, like a bruise, as it clears.

Sometimes there is some thickening of the membranes over the eye which can take several more weeks to smooth over. Very fine dissolving sutures are used to reposition the conjunctival membrane at the end of surgery and until these sutures dissolve there may well be some scratchiness in the eyes. This usually disappears over two or three weeks.

After surgery you should try to keep water out of the eyes for a couple of days. You may shower but please be careful to keep the eyes dry. You must not go swimming for a week. You can resume all other normal activities including heavy exercise two days after surgery. Using your eye, reading, watching TV, etc, will not cause any problems with the surgery.

Risks of surgery

As with any surgery, complications may arise with strabismus operations.

The major risk of surgery is that of not achieving a satisfactory alignment of the eyes. This may be an under-correction (a residual turn in the same direction as originally), or an over-correction (with the eyes now turning the other way).

Typically, an under-correction is more common than an over-correction. Obviously, every effort is made to achieve perfect alignment but this is not always possible. If the alignment is still unsatisfactory at the final post-operative visit, then further surgery may be required.

Double vision is not uncommon in the initial stages after surgery. It usually occurs because there has been an over-correction. Often this will resolve within a few days to weeks but if it fails to resolve by the final post-operative visit then further surgery may be needed.

Infection is an unusual post-operative complication and typically responds well to antibiotic drops. Infection should be considered if you develop discharge or increasing redness and discomfort post-operatively. Please contact your doctor if you are concerned.

Because an incision is made through the conjunctiva and muscle there is always some residual scarring. Usually this is detectable only with microscopic examination, although it may be possible to see it on close examination, particularly if you know it should be there.

As with any eye surgery, there is a theoretical risk of visual loss from strabismus operations, but this is a very, very rare complication. If you have any questions about your operation please don't hesitate to contact your surgeon.

For further information and support talk to an optometrist or eye specialist. Optometrists are listed in the 'Yellow Pages' of your telephone book. Eye specialists are listed with registered medical practitioners at the front of the white pages of your telephone book.

Original material provided by Auckland Eye, and reviewed May 2005. Edited by everybody.