[Squint operation in presbyopic patients].

Since it is well known that the eye musculature undergoes degenerative alterations in old age, the question arises whether squint operations are effective in presbyopic and elderly persons. Twenty-four patients with horizontal squint (average age 63 years) wanted the operation because of diplopia, asthenopia and, in a few cases, for cosmetic reasons; 5 patients were aphakic. The operation was successful in 20 cases. The principles of dosing the operation are essentially the same as for juvenile patients. However, specific difficulties in treating elderly patients arise from: (1) lack of accommodative convergence, as a result of which the squint angle difference between distance and near fixation is usually greater; (2) increasing rigidity of the eye muscles, which diminishes the range of fusion; as a result, the patient is unable spontaneously to compensate for minor squint deviations; (3) senile organic lesions of the bulbs further impair fusion. It is advisable to treat convergent squint by correcting the average deviation between distance and near fixation, preferably shortening the external recti. Cases of divergent squint should preferably be treated by correcting the smaller squint angle, with resection of the external recti. The older the patient is and the worse his fusion, the more precisely the operation has to be dosed. Orthoptic training helps in old patients too.