Comparison of visual quality after corneal surface ablation and stromal ablation surgeries and analysis of the relationship between visual quality and wavefront aberrations

Abstract

Objective To compare higher order aberrations (HOA) and visual quality after corneal surface and stromal ablation surgeries;to evaluate the relationship between subjective visual perception and objective examination results of visual quality. Methods This prospective study in- cluded 116 eyes of 61 patients who underwent refractive surgery;84 eyes of 45 patients underwent laser in situ keratomileusis (LASIK) and 32 eyes of 16 patients underwent advanced surface ablation (ASA). The spherical equivalent (SE) of the LASIK group ranged from -1.25 to -8.75 D, average was (-5.85±1.77)D;the SE of the ASA group was -2.00 to -9.25 D, average was (-5.38±1.83)D. Uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BCVA), spherical and cylindrical values, SE, and wavefront aberrations of patients were recorded before ablation and 1, 3, and 6 months after ablation. A general evaluation and a comparison of pre- and postoperative visual quality and symptoms were done by the same clinician 1, 3, and 6 months after ablation surgery. Results C7, RMS3, RMS6, and RMSh of the ASA group were significantly smaller than that of the LASIK group 1 month after surgery (0.17 vs 0.32, 0.39 vs 0.50, 0.29 vs 0.38, 0.07 vs 0.09, P<0.05). Differences between the groups were smaller 3 and 6 months after surgery. Early postopera- tive scales of driving (diurnal, 2.92 vs 3.44, P<0.01;nocturnal, 2.92 vs 3.19, P<0.05), diurnal distant sight vision (3.40 vs 4.05, P<0.01), nocturnal vision (3.11 vs 3.60, P<0.01), glare (2.70 vs 2.87, P< 0.01) and general vision (3.40 vs 3.95, P<0.01) were lower in ASA group than in LASIK group, while symptoms for the two groups had no significant differences. The scales between the groups 6 months after surgery had no significant differences. Compared with best spectacle corrected vision preopera- tively, diurnal vision improved in most patients, but most patients complained about glare and noc- turnal vision. Early postoperative changes in SE and spherical values negatively correlated with noc- tamai driving, glare, and nocturnal vision vales. Nocturnal symptoms improved during the follow-up period. Symptoms of glare positively correlated with postoperative coma, spherical aberration, and HOA. Conclusion The HOA of the ASA group was smaller than that of the LASIK group. Early postoperative visual quality scales for the ASA group were lower than that of the LASIK group, but the difference disappeared 6 months post-surgery. Larger early postoperative changes in SE, spherical values, and HOA correlated with worse nocturnal visual quality and glare. Key words: Myopia; Keratomileusis,laser in situ; Keratomileusis,subepithelial,laserassisted; Keratomileusis,laser in situ,epipolis; Wavefront aberration; Quality of vision