Abstract
INTRODUCTION: This study aimed to compare changes in retinal oxygen saturation 1 month after femtosecond-assisted laser in situ keratomileusis (FS-LASIK) in Chinese adults with myopia using retinal oximetry. METHODS: In this prospective, observational, single-center cohort study, Chinese adults aged 18-45 years with myopia were categorized into four groups according to spherical equivalent (SE), with 66 eyes characterized as low myopia (LM -3.00D < SE ≤ -0.50D), 68 eyes as moderate myopia (MM -6.00D < SE ≤ -3.00D), 68 eyes as high myopia (HM -9.00D < SE ≤ -6.00D), and 65 eyes as super-high myopia (SHM: SE ≤ -9.00D). The following were measured before and 1 month after FS-LASIK: SE, intraocular pressure (IOP), average keratometry (Km), and axial length (AL). Other ocular biological parameters included retinal arterial oxygen saturation (SaO(2)) and retinal venous oxygen saturation (SvO(2)); parameter difference values are expressed as ∆. RESULTS: Of the 267 participants, 63.30% were female and 36.70% were male. The mean SE, AL, SaO(2), and SvO(2) were -5.93 ± 3.24 D, 26.01 ± 1.35 mm, 93.49% ± 1.67%, and 62.97% ± 4.52%, respectively. Before FS-LASIK, SaO(2) was significantly correlated with AL and SE (r(s) = -0.305, P < 0.001; r(s) = 0.385, P < 0.001). Significant differences were found in SaO(2) across myopia categories (P < 0.001). The changes in the retinal arterial oxygen saturation decreased significantly after FS-LASIK (F = 24.948, P < 0.001). After surgery, SaO(2) demonstrated a statistically significant but weak negative relationship with refractive correction (ΔSE) (r(s) = -0.380, P < 0.001) and axial length (r(s) = -0.404, P < 0.001), a significant but weak positive correlation with average keratometry cutting value (ΔKm) (r(s) = 0.354, P < 0.001), and no correlation with the change in IOP (ΔIOP) (P > 0.05). CONCLUSION: Ruling out the influence of refractive error, SaO(2) was significantly decreased 1 month after FS-LASIK, while there was no significant change in SvO(2). We conjecture that retinal amplification may affect differences in retinal oxygen saturation.