Effect of 4-Horizontal Rectus Muscle Tenotomy on Visual Function and Eye Movement Records in Patients with Infantile Nystagmus Syndrome without Abnormal Head Posture and Strabismus: A Prospective Study

Purpose: To evaluate the effect of tenotomy on visual function and eye movement records in patients with infantile nystagmus syndrome (INS) without abnormal head posture (AHP) and strabismus Methods: A prospective interventional case-series of patients with INS with no AHP or strabismus. Patients underwent 4-horizontal muscle tenotomy. Best corrected visual acuity (BCVA) and eye movement recordings were compared pre and postoperatively. Results: Eight patients were recruited in this study with 3 to 15.5 months of follow-up. Patients showed significant improvement in their visual function. Overall nystagmus amplitude and velocity was decreased 30.7% and 19.8%, respectively. Improvements were more marked at right and left gazes. Conclusion: Tenotomy improves both visual function and eye movement records in INS with no strabismus and eccentric null point. The procedure has more effect on lateral gazes with worse waveforms, thus can broaden area with better visual function. We recommend this surgery in patients with INS but no associated AHP or strabismus.