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

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.

A Case of Cyclic Esotropia Cured by Botulinum Toxin Injection

Cyclic strabismus is a rare entity, which is characterized by alternating periods of strabismus and orthophoria.The mechanism is not clear but seems to be related to the biological clock. Cyclic esotropia is the most common type. On "strabismic"days,a large-angle esotropia will appear, and the binocular vision is impaired. On "straight"days, orthophoria or microstrabismus will appear and no abnor-mal binocular vision is observed. As a treatment, surgery based on the full amount of heterotropia on the strabismic day,has been successful, but treatment by chemodenervation ith botulinum toxin has not been reported yet. Authors experienced the cyclic esotropia following head trauma by a traffic accident in a 3-year-old boy and tried the injection of botulinum toxin on both medial rectus muscles as a treatment. In one-year follow-up observation, the cyclic pattern and esodeviation has disappeared.