Horizontal Saccadic Velocity in Patients with Exotropia Before and After Strabismus Surgery
Miharu Mihara, MD; Kazuya Fujita, MD; Atsushi Hayashi, MD; Ken Kakeue; Ryoi Tamura, MD, PhD
University of Toyama
Introduction: Few studies have compared saccade velocities before and after strabismus surgery. Furthermore, these limited number of studies tested with mixed subject populations of different types of strabismus, movement directions and operative methods. We compared the peak velocities (PVs) of horizontal saccades between normal subjects and patients with exotropia as well as between the pre- and post surgery in the patients.
Methods: Horizontal saccades (adduction and abduction) of monocular vision were recorded by an eye-tracking device in 21 patients with exotropia and 20 normal subjects. Twenty of these patients were examined using the same method after strabismus surgery.
Results: The PVs of adduction and abduction in the patients were higher than those in the normal subjects. Following to the surgery, the PVs of the abduction, but not those of the adduction, of the surgical eye (non-dominant eye) decreased to the level of the normal subjects. However, there was no correlation between changes in the PVs and the amount of surgery (resection and/or recession).
Discussion: The eye alignment correction by the surgery may exhibit this normalizing effect not only through the peripheral (extraocular muscle) mechanism but also through the central nervous mechanism for horizontal saccade accuracy.
Conclusion: The strabismus surgery normalized the patient’s increased PV of surgical eye in the abduction of horizontal saccade.
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