A chronicle of surgical thinking and doing for exotropia: innovations and rediscoveries

Purpose To review the evolution of theories and practices concerning surgery for exotropia over the last approximately 200 years. Methods Major ophthalmology texts and relevant references were reviewed to discover experience and thinking concerning the causes of comitant intermittent and constant exotropia and corrective surgical approaches. Results The concept that excessive divergence is the cause of comitant exotropia has given way to one recognizing that this disorder is a position of rest modified by convergence. Some operations discarded as unreliable or dangerous remain so today. Others continue to be well accepted, whether or not relating to advances in understanding of this condition. Several procedures practiced at former times have regained popularity. Conclusions Concern for the characteristics of extraocular muscle structure and function has led to surgical thinking that goes beyond consideration only of direction and magnitude of deviation. Sophisticated devices now provide heretofore unavailable information consistent with this new approach. The history of progress in surgery for exotropia is mixed. Although some procedures now employed are new, others currently in favor had been well known and formerly utilized by ophthalmologists for many decades. These should be regarded as rediscoveries or revivals rather than as novel. This review also suggests a need to address how to better report retrospective studies.