Quantitative guidelines for exotropia surgery.

The effect of numerous preoperative variables on the amount of surgical correction attained was assessed in a population of intermittent exotropic patients; 54 had bilateral recession surgery, 48 had recess resect surgery. By appropriate multivariate statistical analyses, about 95 per cent of the variance in results of surgery (expressed as change in deviation from preoperative to the postoperative time in prism diopters per millimeter of surgical correction) could be accounted for. A workable scheme for utilizing this data base to guide future surgery is presented in the form of quantitative formulae. In addition to this empirical derivation, insights are provided into the mechanics of ocular muscle operations and the maturation of the eye as it affects strabismus sergery. Expansion of this approach to a wider ranger of cases and to additional types of cases should result in a greater descriptive and surgical accuracy from strabismus surgery.