Vector analysis of astigmatism correction after PRK, FS-LASIK, and SMILE for myopic astigmatism.

Abstract

To compare astigmatic correction among photorefractive keratectomy (PRK), femtosecond laser-assistedin situkeratomileusis(FS-LASIK), and small-incision lenticule extraction (SMILE). This prospective study enrolled 157 eyes that underwent three procedures (59 PRK, 47 FS-LASIK, and 51 SMILE) for the treatment of myopia with low to high astigmatism (- 0.25 to - 4.50 D). Ocular residual astigmatism (ORA) was calculated by vector analysis using refractive (RA) and corneal astigmatism. Vector analysis results were compared in different procedures in the two RA groups (low ≤ 1.00 D and high > 1.00 D) at 3 and 12months postoperatively. There were no significant between-group differences in postoperative safety and efficacy outcomes (all P > 0.05). No significant differences were found in postoperative cylinders between all surgical groups (all p > 0.05), except for 3months postoperative ORA in FS-LASIK (P = 0.004). At 12months, 77%, 59.2%, and 50% of eyes attainemmetropia in the FS-LASIK, SMILE, and PRK groups, respectively. Vector analysis showed comparable values for surgical induced astigmatism, target induced astigmatism, mean error, and angle of error between groups at 12months. Significant differences were observed only in the correction index and difference vector parameters in the astigmatic > 1.00 D group at 3months (P < 0.001), and FS-LASIK was preferable. One-year outcomes revealed that PRK, FS-LASIK, and SMILE were all equally effective in correcting myopic astigmatism. However, FS-LASIK demonstrated more favorable astigmatism correction in eyes with astigmatism > 1.00D in early postoperatively.