Abstract
Purpose :
Changes in saccadic eye movement (SEM) and smooth pursuit (SP) in patients with esotropia (ET) after strabismus surgery are largely unknown, because of few relevant reports. In previous reports, patients with early-onset ET are described with greater asymmetry in the gain in SP between temporal to nasal and nasal to temporal than that of patients with late-onset ET. We investigated the change in horizontal SP and SEM in patients with late-onset ET, particularly acquired comitant esotropia (ACE), comparing pre- to post-surgical data using an eye-tracker.
Methods :
Horizontal SEM and SP of ten patients (mean age: 21.9 ± 8.4 years) with AACE were recorded using a video eye-tracker under binocular viewing before and after strabismus surgery in the non-dominant-eye. To study SEM, the participants were instructed to fixate their gaze on a target located in the center at the beginning of the test trial, and to fixate on a new target as rapidly as possible when it randomly appeared at either 18.3°-rightward or 18.3°-leftward. To study SP, the participants were asked to track a step-ramp target moving at ±6.1°/s horizontally as accurately as possible. The asymmetry in the adduction−abduction gain of each SEM and SP and the differences in the gain in each SEM and SP between the right and left eyes, that is, binocular coordination, were compared between the pre- and post-surgical data.
Results :
After the surgery, the gain in SEM of the adduction in the both eyes and the abduction in the dominant-eye decreased. The asymmetry of adduction−abduction gain of SEM in each eye after surgery was significantly larger than that before surgery. The differences in the gain of SEM between both eyes in rightward and leftward decreased after surgery, but not significantly. The asymmetry of adduction−abduction after surgery in the gain in SP in each eye was smaller than that before surgery, but not significantly. After surgery, the left-right eye difference in gain of SP in the non-dominant eye direction decreased significantly.
Conclusions :
Ocular alignment correction by strabismus surgery in patients with ACE results in an improvement in the binocular coordination of SP, not SEM, because SP needs visual feedback.
This is a 2020 ARVO Annual Meeting abstract.