Factors influencing the self-reported sense of deviation in adults with successful surgical outcomes for strabismus

Background To determine whether a sense of deviation remains in adults with successful motor alignment who fulfil diplopia criteria after surgery and to examine the factors associated with this judgement. Methods This was a retrospective study. Adult patients defined as having a successful outcome based on more than 1 year of post-operative follow-up visits were included in the study. The sense of deviation was determined at the last visit. Pre- and post-operative deviation and characteristics including age, gender, education level, occupation, diagnosis, size of deviation, extraocular movement (EOM), binocular function, and health-related quality of life (HRQOL) were recorded. Results In total, 22 (24%) of the 91 adults with successful surgical outcomes reported a sense of deviation. No significant differences were noted between subjects with and without a sense of deviation regarding patient demographics, pre- and post-operative deviation, changes in deviation, sensory fusion or EOM. Subjects with a sense of deviation had an increased prevalence of and larger post-operative vertical deviation, poorer stereo function, and lower HRQOL scores than those with no sense of deviation. The presence of post-operative vertical deviation was associated with a sense of deviation. Conclusions Approximately one-fourth (24%) of adults defined as having successful surgical outcomes who still had a sense of deviation exhibited worse stereo function, higher vertical deviation size and lower HRQOL scores. The presence of 3 to 5 prism dioptres(pd) of vertical deviation would be the main factor associated with a sense of deviation post-operatively.