Visual recognition time in strabismus: small-angle versus large-angle deviation.

To measure the possible differences in monocular detection time of a threshold visual acuity stimulus generated on a computer screen (recognition time, RT) between patients with small-angle and large-angle strabismus. Five patients with small-angle esotropia (<=7°) and five with large- angle esotropia (15-20°) were tested. Six age-matched normal subjects served as control. The recognition time (RT1) of the threshold stimulus was measured in both eyes sequenctially. Moreover, we measured the recognition time 2 (RT2) defined as the time necessary for identifying the same threshold visual acuity stimulus generated in the moment in which fixation is taken up by one eye after occlusion of the fellow eye. The ANOVA for repeated measures indicated that mean RT 2 was significantly longer in large-angle strabismic eyes when compared with that of normal control eyes. We hypothesized that alternating strabismus patients may have a significant advantage in maintaining a small-angle deviation.