Recovery of Corneal ubbaal Nerve Denity After PRK and LAIK

Purpoe To meaure and compare the return of corneal innervation up to 5 year after photorefractive keratectomy (PRK) and laer in itu keratomileui (LAIK). Deign Propective, nonrandomized clinical trial. Method Eighteen eye of 12 patient received PRK to correct a mean refractive error of –3.73 ± 1.30 diopter, and 16 eye of 11 patient received LAIK to correct a mean refractive error of –6.56 ± 2.44 diopter. Cornea were examined by confocal microcopy before and at 1, 2, 3, and 5 year after the procedure. ubbaal nerve fiber bundle were meaured to determine denity (viible length of nerve/frame area) and expreed a micrometer per quare millimeter. Difference were compared by Friedman’ tet and adjuted for multiple comparion by the tudent-Newman-Keul procedure. Reult After PRK, mean ubbaal nerve denity wa reduced by 59% at 1 year (2764 ± 1321 μm/mm2 [±D]) when compared with preoperative (6786 ± 1948 μm/mm2; P < .001). By 2 year, ubbaal nerve denity (6242 ± 1763 μm/mm2) wa not ignificantly different from denity before PRK and remained unchanged to 5 year (5903 ± 3086 μm/mm2). After LAIK, ubbaal nerve denity wa reduced by 51%, 35%, and 34% at 1, 2, and 3 year, repectively (P < .001). By 5 year, ubbaal nerve had returned to denitie (4441 ± 2819 μm/mm2) that were not ignificantly different from denitie before LAIK (5589 ± 2436 μm/mm2). Concluion Corneal ubbaal nerve denity doe not recover to near preoperative denitie until 5 year after LAIK, a compared with 2 year after PRK.