Clinical Characteristic and Tear Film Biomarkers After Myopic FS-LASIK: 1-Year Prospective Follow-up

Abstract

Purpose: To assess the long-term (1-year) effect of myopic femtosecond laser–assisted in situ keratomileusis (FSLASIK) on clinical characteristics and tear film biomarkers. Methods: Eighty eyes from 80 patients who underwent FSLASIK were evaluated. Ocular surface symptoms and signs were evaluated using specific questionnaires and tests. The corneal nerves and dendritic cells were examined using in vivo confocal microscopy. Corneal sensitivity was evaluated using a Cochet-Bonnet esthesiometer. Tear inflammatory cytokines and neuropeptides were evaluated using Luminex immunoassay. These examinations were performed preoperatively and at 1, 3, 6, and 12 months postoperatively. Results: Seventy-three participants completed all follow-up visits. Following FS-LASIK, ocular symptoms and signs (except Schirmer I test) worsened at 1 month but corneal and conjunctival stainings improved by 3 months. The numbers of dendritic cells and activated dendritic cells increased at the 3-month postoperative visit and recovered to preoperative levels by the 6-month visit. Ocular symptoms and corneal sensitivity recovered to preoperative levels at the 12-month visit. Tear break-up time and corneal nerve morphology were not recovered to preoperative status at the 12-month visit. Interleukin (IL)-1β, IL-17A, tumor necrosis factor-α, and substance P tear levels significantly increased at all postoperative visits compared to preoperative levels. Corneal staining scores positively correlated with tear IL-1β and IL-17A levels, whereas corneal nerve morphology positively correlated with corneal sensitivity and negatively correlated with substance P levels. Conclusions: Although most clinical variables improved at 12 months postoperatively, some tear inflammatory cytokines and substance P remain altered beyond 12 months, indicating that ocular homeostasis is not completely recovered. [ J Refract Surg . 2024;40(8):e508–e519.]