Outcome study of bilateral lateral rectus recession for intermittent exotropia in children.

PURPOSE: This paper reports an outcome study of 52 consecutive children treated by bilateral lateral rectus recession for intermittent exotropia over a 9 year period (1981-90) with a minimum follow up of 6 months.
METHODS: Successful alignment was defined as the absence of any postoperative intermittent or constant tropia in any position of gaze. The study examined the variables that might be predictive of successful alignment. The charts were abstracted for age at initial surgery, quantity of initial deviation, initial refraction, motor alignment at 1 week and 6 months, final alignment, secondary surgery results and the incidence of a monofixation syndrome result.
RESULTS: Motor tests demonstrated that 32 (62%) of the patients were successfully aligned by the initial procedure performed for a mean of 25 prism diopters of preoperative deviation while viewing distant targets at a mean age of 4 years 8 months, followed for a mean of 4 years, 4 months. The incidence of undercorrections and overcorrections were approximately equal in quantity suggesting that the current surgical dosage was adequate, but the age at initial surgery, initial deviation, initial refraction and 1 week postoperative alignment results were not predictive of success. Alignment at 6 months, however, was highly correlated with successful alignment by the end of the study (p = 0.002). Secondary surgery was performed for 11 patients and 5 patients were found to have a monofixation syndrome result.
CONCLUSION: Successful alignment was achieved in the majority of children treated for intermittent exotropia by an initial bilateral lateral rectus recession. However, 20% of the patients received secondary surgery for a residual deviation, and the study confirmed a previously reported 10% incidence of monofixation syndrome result in children surgically treated for this type of strabismus.