The purpose of this study was to determine whether an equal amount of exotropia (XT) or esotropia (ET) produces a more noticeable eye turn, which gives the better impression of eye contact, and how a positive angle kappa (K) affects this judgment.
Images from a white male model were manipulated to simulate 0, 5, 10, and 15° of ET and XT for both 0 and +5° K. A series of image pairs was then created that juxtaposed XT and ET of equal angles for both 0 and +5° K. Forty-five optometry students then judged which image in each pair appeared to have the greater tropia and which gave the greater impression of eye contact.
When angle kappa was 0, there was no significant difference in whether XT or ET appeared to be more noticeable. However, when angle kappa was +5°, an XT of 5° or greater became more apparent than an equal ET (p < 0.001). However, when the criterion was eye contact, ET gave the greater impression that eye contact was being made when the deviation was 10° or more, and this was true for both 0 and +5° K (p < 0.001).
When a strabismus is to be evaluated or corrected purely for cosmetic reasons, the results may differ depending on the value of angle kappa and whether the criterion for good cosmesis is ocular deviation or eye contact.