Abstract
Purpose: :
We characterize the effects of eye muscle surgery in a young cohort of patients with INS.
Methods: :
This is a prospective, comparative, interventional case series of 19 patients. All had an associated head posture or strabismus. All had two virgin recti on each eye operated on with some having a superior or inferior oblique muscle surgery for a chin up or down posture. All patients were followed for a minimum of 12 months. Outcome data and measures were obtained clinically with Teller acuity testing and with eye movement recordings and included: demography, associated eye/systemic conditions and Pre- and Post-Operative; Binocular Best Corrected Teller Acuity (BCTA), Anomalous Head Posture (AHP), Strabismic Deviation (SD), null zone width (NZW) and Nystagmus Optimal Foveation Fraction (NOFF), absolute foveation time (FOV) and null zone waveform changes (NZW).
Results: :
Patients ranged in age from 5-23 mos (ave 17.4 mos), follow up averaged 14.0 mos, 8 had associated systemic disease, preoperative head postures in 13 (68%) ranged from 15 to 35 degrees. The most common associated ocular conditions were strabismus in 15 (79%), ammetropia in 13 (68%), and amblyopia in 9 (47%) and optic nerve, foveal or generalized retinal disease with or without albinism in 15 (79%). Regardless of the amount of head posture in degrees, after surgery, all patients significantly (p < 0.05) improved in AHP. There were significant (p <0.05) improvements, SD, NOFF. FOV and NZW. Group mean BCTA significantly improved (p<0.03). There were none who required a second operation and only a conjunctival suture related cyst occurred in two eyes.
Conclusions: :
This study provides evidence that extraocular muscle surgery in the first two years of life in patients with INS waveformsfavorably changes their head posture, vision and nystagmus characteristics. Thus adding further evidence that eye muscle surgery positively affects the oscillation of INS and subsequent function
Keywords: nystagmus • eye movements • strabismus: treatment