The reliability of adjustment in strabismus surgery

It has been recommended that the position of the operated muscles be adjusted shortly after strabismus surgery to achieve better alignment on the first postoperative day and thereby ensure satisfactory later alignment. We compared prism cover test measurements on the first postoperative day with measurements within the first few months after surgery to determine whether day 1 measurements remained stable or whether they changed significantly, providing an inaccurate basis for adjustment. Our study found a fairly large variability in the deviation between the first and last day of the study. Eighteen percent of patients varied by 5 to 9D, and 49% differed by > 10D or more. Equally important was the finding that, had an adjustment been made, it would have made the final result worse than without adjustment. Both of these factors would seem to indicate a degree of variability that controverts the predictability of the adjustment procedure.