Variability of XXXX in Strabismus.

@entity1 @entity2194 @entity7085 @entity4457
Importance: In strabismus, the fixating eye conveys the direction of gaze while the fellow eye points at a peripheral location in space. The stability of the eyes may be reduced by the absence of a common target. Objective: To quantify the stability of eye position in strabismus and to measure variability in the @entity2194 . Design, Setting, and @entity1 : From 2010 to 2014, a prospective comparative case study of 25 @entity1 with alternating exotropia with normal visual acuity in each eye and 25 control individuals was conducted in a laboratory at a tertiary eye center. A video eye tracker was used to measure the position of each eye while @entity1 alternated fixation on the center of a cross under dichoptic conditions or scanned pictures of natural scenes. Main Outcomes and Measures: Spatial and temporal variability in the position of the fixating eye and the nonfixating eye in @entity1 with strabismus and control individuals, quantified by the log area of @entity7085 containing 95% of eye positions or mean SDs of eye position. Results: In the 25 @entity1 with strabismus, the mean (SD) age was 28 (14) years (range, 8-55 years) and the mean (SD) @entity2194 was 14.2   (5.9  ) (range, 4.4  -22.4  ). In the @entity1 with strabismus, the mean position variability (1.80 log units; 95% CI, 1.66-1.93) for the deviating eye was greater than for the fixating eye (1.26 log units; 95% CI, 1.17-1.35) (P   <   .001). The fixating eye of @entity1 with strabismus was more variable in position than the fixating eye of individuals without strabismus (0.98 log units; 95% CI, 0.88-1.08) (P   <   .005). Conclusions and Relevance: In @entity1 with strabismus, even without @entity4457 , the deviated eye is more variable in position than the fixating eye. Both eyes are less stable in position than the eyes of control individuals, which indicates that strabismus impairs the ability to fixate targets steadily. Saccades contribute to variability of the deviation angle because they are less conjugate in @entity1 with strabismus.
