Analysis on the Correlation Between Long-term Refractive Regression and Visual Quality after FS-LASIK

To record the long-term visual quality after FS-LASIK and analyze the effect of long-term refractive regression after corneal laser surgery on visual quality.

Seventy-eight patients (153 eyes) who had undergone FS-LASIK more than 5 years before and had undergone follow-ups between November 2020 and March 2021. We collected data on the patients' age of surgery, postoperative period, and preoperative diopters (corrected to LogMAR 0.0 by mydriatic optometry). We obtained the measurements of ARC, PRC, THP by Pentacam, and extracted values for UCVA(LogMAR), CTRmsTotal, CTRmsHO, RmsTotal, RmsHO, MTFTotal, MTFHO, PSFTotal, PSFHO, Coma-T, Coma-CT, SA-T, SA-CT, Trefoil-T, and Trefoil-CT measured with OPD Scan III. We allocated the patients into emmetropia group (SE≤ -0.5 D) 40 patients (78 eyes) and regression group (SE > -0.5D) 38 patients (75 eyes) based on their postoperative diopters.

The values for postoperative periods, preoperative diopters, CTRmsTotal, CTRmsHO, and RmsTotal, Coma-CT, CTSA-CT in the emmetropia group were significantly lower than those in the regression group. The age of surgery, UCVA, MTFTotaL, MTFHO, PSFTotal, and CTPSF values in the emmetropia group were significantly higher than those in the regression group. The ARC, PRC, THP, RmsHO, Coma-T, SA-T, Trefoil-T, and Trefoil-CT values were similar in both groups. There was no significant difference in preoperative sphere, spherical equivalent and BCVA between the two groups. There were significant differences in postoperative parameters at 1 year, 3 years, and 5 years. The postoperative diopter value was significantly correlated with age of surgery, postoperative period, THP, MTFTotal, PSFTotal, Coma-T, and SA-CT.

After FS-LASIK, young patients with relatively thin cornea are susceptible to refractive regression. With the extension of postoperative period, refractive regression may aggravate. There was no significant correlation between postoperative refractive regression and higher order aberrations.