To investigate the alterations in wavefront aberration, contrast sensitivity (CS) and objective scatter index (OSI) at early posterative period after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) combind with accelerated corneal collagen crosslinking (ACXL).

This was a prospective, non-randomized controlled study. From June 2020 to March 2021, 140 eyes of 70 patients with thin cornea and myopic astigmatism were enrolled in Beijing Tongren Eye Center. The patients were assigned to FS-LASIK-ACXL group (70 eyes of 35 patients) and FS-LASIK group (70 eyes of 35 patients). Refractive surgery was began with a Visumax femtosecond laser made corneal flap, followed by a Ex500 excimer laser aided corneal ablation. For eyes in ACXL group, ACXL was performed immediately after the FS-LASIK. Patients were followed up at 1 day, 1 week, 1 month and 3 months. Repeated measures analysis of variance and independent sample t-tests were used to compare the difference in above refractive parameters between two groups.

The baseline spherical equivalent (SE) in ACXL group and FS-LASIK group were -7.52±1.88 D and -7.63±1.96 D, respectively, which decreased to -0.03±0.59 D and -0.03±0.56 D, repectively at 3 months after the surgery (F=246.73, P<0.001;F=236.78, P<0.001). Both procedures significantly improve the LogMAR uncorrected distance visual acuity (UDVA) of the patients (1.30±0.28 to -0.09±0.07 in ACXL group and 1.31±0.21 to -0.08±0.06 in FS-LASIK group) at 3-month follow-up (F=400.32, P<0.001;F=703.42, P<0.001). The surface asymmetry index (SAI), root mean square value of high-order aberrations (RMSh) and OSI achieved significantly increase in both groups at all follow-up times (P<0.05). The surface regularity index (SRI) decreased in FS-LASIK group, but increased in ACXL group, and achieved the highest value at 1 month (F=10.92, P<0.001;F=3.20, P=0.047). Postoperatively, Log values of CS in FS-LASIK group increased at 1.5, 3.0, 6.0, 12.0 and 18.0 cycles per degree (c/d) (P<0.05), while this parameter only increased at 3.0 and 6.0 c/d in the ACXL group (F=7.07, P=0.001; F=3.31, P=0.039). The total scores for quality of vision increased in both groups after the surgery, and achieved the highest values at 1 month (F=2.85, P=0.040; F=3.27, P=0.025).

Although increased corneal irregularity and scattering index occur in the early post-operative period after FS-LASIK combined with ACXL and may subsequently impact the CS and subjective feelings, the post-operative visual acuity and refractive diopter are still satisfactory.

laser in situ keratomileusis; corneal collagen crosslinking; visual quality; wavefront aberration; contrast sensitivity