Impact of femtosecond laser-assisted in situ keratomileusis on retinal ganglion cell function.

Abstract

PURPOSE\nTo analyse the effect of femtosecond laser-assisted in situ keratomileusis (FS-LASIK) on the electrical response of retinal ganglion cells using pattern electroretinography (pERG).\n\n\nMETHODS\nThis was a longitudinal, prospective, observational pilot study. We included consecutive myopic patients who underwent FS-LASIK to correct up to 6\u2009dioptres of myopia and up to 2\u2009dioptres of astigmatism. Patients with excessive blinking or tearing and those with Snellen uncorrected visual acuity less than 0.9\u2009dec on postop day 1 were excluded. Diopsys NOVA® (Diopsys Inc., NJ) pERG records, using high- and low-contrast patterns, were obtained 16\u2009h and 1\u2009month after FS-LASIK was performed. Magnitude (μV), Magnitude D (μV), Magnitude D/Magnitude ratio and signal-to-noise ratio (dB) were analysed. Wilcoxon test for nonparametric paired data was employed.\n\n\nRESULTS\npERG data from 24 eyes were analysed from 24 patients who underwent FS-LASIK. Mean age was 35.79\u2009±\u20099.86\u2009years. Mean preoperative refraction was -2.69\u2009±\u20097.6\u2009D (spherical) and -0.38\u2009±\u20090.40\u2009D (cylinder). Mean surgical time was 56.88\u2009±\u20097.6\u2009s. No statistically significant differences were obtained for any of the studied parameters when comparing 16\u2009h with 1\u2009month after FS-LASIK, with the exception of Magnitude with low contrast, which increased from 1.21\u2009±\u20090.2 to 1.39\u2009±\u20090.29\u2009µV at 16\u2009h and 1\u2009month postoperatively, respectively (p\u2009=\u20090.03).\n\n\nCONCLUSIONS\nFS-LASIK seems to induce a mild and transitory defect in retinal ganglion cell function. Only a mild decrease was detected in the magnitude value for low-contrast stimuli when pERG was performed 16\u2009h postoperatively, and it returned to normal 1\u2009month after surgery.