Purchase this article with an account.
Miharu Mihara, Atsushi Hayashi, Ken Kakeue, Ryoi Tamura; Longitudinal change in smooth pursuit in patients with intermittent exotropia after strabismus surgery . Invest. Ophthalmol. Vis. Sci. 2019;60(9):4431.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
An experimental study involving monkeys with exotropia showed that change in gain of smooth pursuit noted immediately after surgery returned to the preoperative level by 6 months after operation. Longitudinal change in smooth pursuit in a human model of strabismus following strabismus surgery remains unclear. Thus, the present study aimed to observe the change in horizontal smooth pursuit in patients with intermittent exotropia before and after strabismus surgery.
Smooth pursuit of nine patients (mean age: 22.2 ± 13.9 years) with intermittent exotropia was recorded by using a video eye-tracker before and after unilateral lateral rectus muscle recession and medial rectus resection (1 week, 1 month, 3 months, 6 months). They were asked to track a step-ramp target moving at ± 6.1°/s horizontally as accurately as possible under binocular viewing. The differences in gain (eye velocity divided by target velocity) and amplitude of smooth pursuit between the right and left eyes were compared between before and after surgery. In addition, we investigated the correlation of their value of gain and amplitude with the deviation.
Preoperative ocular deviation at near was 59.1 ± 34.7 prism diopter (PD). The differences in gain and amplitude between the left and right eyes were 0.23 ± 0.1 and 3.0° ± 3.7°, respectively. These values were improved at 1 week after surgery (gain: 0.08 ± 0.06, amplitude: 0.9 ± 0.65), and continued to improve for 6 months after surgery; however, ocular deviation at near reverted from 5.9 ± 10.5 PD to 18.9 ± 17.5 PD by 6 months after surgery. The correlation between the differences in pursuit amplitude, gain and ocular deviation was significant.
Surgical correction of ocular deviation improves binocular coordination of smooth pursuit in patients with intermittent exotropia. In the long term, the return of the eye position occurs mildly, but the improvement of the smooth pursuit gain tends to remain for a long time.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
This PDF is available to Subscribers Only