The use of (a)symmetry of the rest position of the eyes under general anesthesia or sedation-hypnosis in the design of strabismus surgery: A favorable pilot study in 51 exotropia cases

Background and Purpose: Studies support techniques of intraoperative adjustment under general anesthesia, of eye muscle surgery, based upon the rest position (deviation) to improve surgical results. None, however, have examined the (a)symmetry, per se, of the rest position and its influence on surgical outcomes. Methods: Retrospective/prospective patient chart data and photographs taken of patients under anesthesia were judged for (a)symmetry of deviation and correlated with (a)symmetry of surgery performed on 51 exotropic patients. Two groups were compared: 'matched' (symmetrical surgery for symmetrical deviations and asymmetrical surgery for asymmetrical deviations) and 'opposite' in which the reverse was performed. Results: Sensory results were 'statistically significantly' better (p=0.027), the need for postoperative adjustment of adjustable sutures was 'statistically significantly' less (p=0.031) and the motor results tended to be improved (p=0.237) ('clinically/medically significant') when surgery was 'matched' to the deviation under anesthesia. Conclusion: Use of the (a)symmetry of deviations under anesthesia can improve surgical results. Therefore, the final decision as to which muscles to operate on might best be delayed until the time of surgery when that (a)symmetry can be observed. This pilot study should be confirmed by a proper completely prospective randomized study.