Outcomes after surgery for INS
Reviewed by Fiona Rowe

The purpose of this study was to detail clinical and electrophysical outcomes after extraocular muscle surgery in adults with infantile nystagmus syndrome (INS). This was a single centre prospective case series of 81 patients aged 18-72 years (mean 36); 63% male. A surgical algorithm was outlined according to nystagmus type based on abnormal head posture and strabismus type. Follow-up averaged 14 months (13-78). About 80% had associated ocular or systemic diagnosis; 44% with abnormal head position (AHP), 69% strabismic, 79% significant refractive error. Average group mean best corrected visual acuity improved significantly after treatment: 0.55 ±0.16 to 0.41 ±0.11 logMAR. Twenty-three of 38 adults previously ineligible to drive became eligible. There was a significant increase in group mean primary position strabismus angle. Ninety-three percent had postoperative deviations within 10PD horizontal and 6PD vertical. There were no cases of persistent diplopia postoperatively. A significant improvement in AHP was seen postoperatively. Twenty-three of 36 adults (83%) were within 10 degrees of ortho postoperatively. There was a significant increase for contrast sensitivity and NAFX foveation values. The authors acknowledge this as a single centre study but conclude significant and sustained improvement in visual function measures were obtained for adult patients with INS treated by surgery.

Clinical and electrophysical outcomes after eye muscle surgery in 81 adults with infantile nystagmus syndrome.
Hertle RW, Curtis M, Boydstun I, et al.
JOURNAL OF PEDIATRIC OPHTHALMOLOGY AND STRABISMUS
2021;58:93-104.