Quality of Vision After LASIK, PRK and FemtoLASIK: An Analysis Using the Double Pass Imaging System HD AnalyzerTM(®)

PURPOSE: Analyze and compare the quality of vision of Photorefractive keratectomy (PRK), LASER in situ keratomileusis with mechanical microkeratome (LASIK) and femtosecond-assisted LASIK (FS-LASIK) using the double-pass imaging system HD AnalyzerTM(®). SETTING: Ophthalmology department of Centro Hospitalar Universitário do Porto (CHUPorto). DESIGN: Retrospective, non-randomized, single center study. METHODS: Analysis of three equivalent groups of patients submitted to PRK, LASIK and FS-LASIK at our department. The objective quality of vision assessment included the objective scatter index (OSI), the modular transfer function cutoff frequency (MTF) and the predicted visual acuity within the 100% (PVA), 20% (PVA20) and 9% contrast levels (PVA9) that were evaluated at baseline, 1st week, 1 and 6 months after surgery. RESULTS: 118 eyes were included: 40 underwent LASIK, 43 FS-LASIK and 35 PRK. The mean age was 30.6±4.6 years old and 56% were female. There was a significant impact concerning the type of procedure in the objective quality of vision analysis (Repeated measures ANOVA): the FS-LASIK group showed lower OSI values overtime [F(1,2)=4.566, p=0.012, OSI 0.83±0.53 (FS-LASIK) vs 0.87±0.47 (PRK) and 1.21±1.44 (LASIK)], higher MTF values [F(1,2)=6.569, p=0.002, MTF 40.17±8.33 vs 32.37±11.4 (PRK) and 30.26±10.28 (LASIK)], higher PVA 100% [F(1,2)=10.871, p<0.001], PVA 20% [F(1,2)=9.737, p<0.001] and PVA 9% [F(1,2)=6.335), p=0.003]. CONCLUSION: In our study, FS-LASIK showed an excellent optical performance through the HD AnalyzerTM technology, with significantly lower OSI and higher MTF, PVA100, PVA20 and PVA9 values. According to our results, this procedure seems to be superior to PRK and LASIK regarding visual quality objective parameters.