Comparative study of objective visual quality between FS-LASIK and SMART in myopia

AIM:To compare the changes in the objective visual quality of patients with low and moderate myopia postoperatively after transepithelial photorefractive keratectomy using the smart pulse technology(SMART)and femtosecond laser in situ keratomileusis(FS-LASIK).METHODS:Corneal higher-order aberrations(HOAs),horizontal coma,vertical coma and spherical aberration were measured using Pentacam,and cutoff for modulation transfer function(MTF cutoff),objective scatter index(OSI)and Strehl ratio(SR)was measured using an optical quality analysis system(OQAS-II),before and after operation at 1,3,and 6 mo,and data were analyzed by repeated measurement two-way analysis of variance.RESULTS:The difference in uncorrected distance visual acuity between SMART and FS-LASIK was statistically significant only 1 wk postoperatively.Approximately 86.36%and 80.69%of patients with spherical equivalent(SE)in±0.50 D were observed in the SMART and FS-LASIK groups,respectively.No significant difference was observed in SE between the two groups(P=0.509).The HOAs increased postoperatively compared with those before surgery in both groups(P<0.05).No significant difference in HOA,corneal horizontal coma,spherical aberration,ΔHOA,Δhorizontal coma,andΔspherical aberration were observed between the two group(P>0.05).Corneal vertical coma andΔcorneal vertical coma in the FS-LASIK group were higher than those in the SMART group(P<0.05).The OSI of both groups at 1 mo after surgery was higher than that before surgery(P<0.05).At 3 and 6 mo postoperatively,the OSI in the FS-LASIK group was slightly higher than that in the SMART group(P=0.040 and 0.047,respectively).At 6 mo after surgery,the MTF cutoff was statistically significant different between the two groups(P=0.026).No significant difference in SR between the FS-LASIK and SMART groups was observed at 1,3,and 6 mo postoperatively(P>0.05).CONCLUSION:The HOAs increase and visual quality is delayed in both groups postoperatively,and the long-term objective visual quality after SMART is slightly better than that after FS-LASIK.

SmartSurf^(ACE)transepithelial photorefractive keratectomy with mitomycin C enhancement after small incision lenticule extraction

Background:To evaluate predictability,stability,efficacy,and safety of transepithelial photorefractive keratectomy(TPRK)using smart pulse technology(SPT)(SmartSurface procedure)of Schwind Amaris with mitomycin C for correction of post small incision lenticule extraction(SMILE)myopic residual refractive errors.Method:This study is a prospective,non-comparative case series conducted at a private eye centre in Ismailia,Egypt,on eyes with post-SMILE myopic residual refractive errors because of undercorrection or suction loss(suction loss occurred after the posterior lenticular cut and the creation of side-cuts;redocking was attempted,and the treatment was completed in the same session with the same parameters)with myopia or myopic astigmatism.The patients were followed up post-SMILE for six months before the SmartSurface procedure,and then they were followed up for one year after that.TPRK were performed using Amaris excimer laser at 500 kHz.The main outcomes included refractive predictability,stability,efficacy,safety and any reported complications.Results:This study included 68 eyes of 40 patients out of 1920 total eyes(3.5%)with post-SMILE technique myopic residual refractive errors.The average duration between the SMILE surgery and TPRK was 6.7±0.4 months(range 6 to 8 months).The mean refractive spherical equivalent(SE)was within±0.50 D of plano correction in 100%of the eyes at 12 months post-TPRK.Astigmatism of<0.50 D was achieved in 100%of the eyes.The mean of the residual SE error showed statistically significant improvement from preoperative−1.42±0.52 D to 0.23±0.10 D(P<0.0001).Uncorrected distance visual acuity(UDVA)(measured by Snellen’s chart and averaged in logMAR units)was improved significantly to 0.1±0.07(P<0.0001).UDVA was 0.2 logMAR or better in 100%of the eyes,0.1 logMAR or better in 91.2%of the eyes,and 0.0 logMAR in 20.6%of the eyes.Corrected distance visual acuity(CDVA)remained unchanged in 79.4%of eyes.14.7%of eyes gained one line of CDVA(Snellen).5.9%of eyes gained two lines of CDVA(Snellen).Conclusion:Transepithelial photorefractive keratectomy using smart pulse technology with mitomycin C enhancement after SMILE is a safe,predictable,stable,and effective technique.