The Change in Deviation Angle with Time Course after Surgical Correction of Intermittent Exotropia

ABSTRACT

PURPOSE: To evaluate the amount and pattern of change in deviation angle with time course after surgical correction of intermittent exotropia and to evaluate the effect of pre-operative deviation and operation age on post-operative deviation change. METHODS: 54 patients who followed more than 60 months (60~120 months, mean 71.7 months) after surgical correction of intermittent exotropia were selected. We defined 'satisfactory results' that alignment of orthotropia, under 10delta esotropia and under 10delta exotropia. RESULTS: Of 54 patients, satisfactory results obtained in 96.2%(52 patients), immediate post-operation day and decreas with time course to 35.1% (19 patients) at post-operative 5 years. To quantification of change of deviation, author defined exotropic drift as +, esotropic drift as -, and no change as 0. The change of deviation between immediate post-operation and 2 years after operation is +14.55delta, between 2 years after and 5 years is +2.70delta. The change of deviation developed between immediate post-operation and 2 years after operation has statistical significance in comparison with change of deviation developed between after 2 years and 5 years after operation (P=0.0001). Pre-operative deviation has no effect on post-operative deviation change (P=0.4472) and operation age was same (P=0.3461). CONCLUSIONS: The results of surgical correction of intermittent exotropia is significantly deteriorated with time course. Exotropic drift was more pronounced between immediate post-operation and 2 years after operation and then decreased. Therefore we recommend that after surgery of intermittent exotropia patients should be followed by schedule more than 2 years and thereafter the tendency for exotropic drift will more stable. After 2 years, however, small amount exotropic drift can be possible.