The adjustment of the muscles of the eye to correctly align the eyes is the most common eye operation performed in children.Eyes can be straightened virtually at any age- from as early as 4-5 months and whenever necessary in adulthood. A squint operation may take from 15-40 minutes.
The procedure is relatively straightforward and the results are good but not perfect. In most patients there is an 80-90% chance of the eyes being correctly aligned postoperatively. This means more than one operation will sometimes be required. The phases of the operation are-
It is extremely important to accurately measure the angle of deviation preoperatively. This is performed using prisms to neutralise the turn. It is also necessary to know preoperatively whether there is any paralysis or restriction of function of the eye muscles as this can affect the outcome and limit chance of correction.
In children a General Anaesthetic is employed.Adults can in certain circumstances have the procedure performed under Local Anaesthetic. This makes it possible to optimise alignment in the course of the procedure.
If this is not possible, in older children or cooperative adults an "adjustable suture" technique can be combined with a General Anaesthetic so that alignment can be optimised postoperatively.
The loose lining (skin) of the eye is opened to allow the anterior end of the eye muscles to be viewed.
The eye muscles are approached, with the eye in place, at the anterior end. The muscle may be tightened by removing a small segment (resection) and reattaching it to the eye or conversely loosened by reattaching the muscle further posteriorly on the globe (recession). Other procedures may be utilised to vary the muscle's effect on movement- (eg transposing the muscle to affect rotation).
The lining is reapplied and sutured into place.