Effect of the Photorefractive Keratectomy on Improvement of Involuntary Eye Movements and Visual Function in Myopic Patients with Congenital Nystagmus

To determine the effect of photorefractive keratectomy (PRK) on improvement of involuntary eye movements and visual functions in myopic patients with congenital nystagmus. This prospective interventional case series included patients with congenital nystagmus and myopia ≥ -1 D who underwent PRK over a 2-year period. Complete ophthalmological examinations including visual acuity, contrast sensitivity and video-nystagmography were performed and compared before and 3 months after PRK. A total of 24 eyes of 12 patients with a mean age of 23±2 years were enrolled in the study. Spherical equivalent was -2.82 ± 1.65 preoperatively and -0.26 ± 0.25 postoperatively (P<0.001). Pre- and postoperative mean sphere was -2.16±1.36 and -0.10±0.35 and astigmatism was -1.33 ± 1.14 and -0.31 ± 0.51, respectively (P<0.001 for both comparisons). Mono-ocular visual acuity was improved from 0.36±0.21 in LogMAR preoperatively to 0.27±0.25 LogMAR postoperatively (P<0.001). Binocular visual acuity was significantly improved from 0.33±0.2 LogMAR to 0.17±0.16 LogMAR (P<0.001). A significant increase in contrast sensitivity was observed in low (P<0.001), intermediate (P<0.001) and high (P=0.01) spatial frequencies. Frequency, amplitude and intensity of nystagmus were significantly decreased after PRK (p<0.001). There was no correlation between degree of myopic correction and improvement in sensory and motor indices of nystagmus (P>0.1 for all correlations). PRK in patients with congenital nystagmus increased mono-ocular and binocular vision. Additionally, contrast sensitivity and motor indices of nystagmus (frequency, amplitude and intensity) were significantly improved postoperatively.