A Comparison of Visual Acuity, Refractive Outcomes, and Satisfaction Between LASIK Performed with a Microkeratome and a Femto Laser Nauman hashmani (MBBS), sharif hashmani (FCPS) Hashmanis Hospital, pakistan

Financial Interests There are no financial interests to note.

The World on the Modalities Two meta-analysis have been conducted in 2012 Neither found better efficacy However one found a better predictability in the FAL One found fewer HOAs in the FAL arm Both these incorporated low frequency high impulse lasers. Some studies demonstrate a difference in recovery time as the primary difference, in terms of refractive outcomes and efficacy. Another meta-analysis demonstrates differences in the various femto lasers used.

Methods This was a retrospective study involving two arms: LASIK with a Hansatome microkeratome (HM) and LASIK with a femto laser (FAL) 687 patients (1366 eyes) were included 1137 eyes treated by HM 229 by FAL Study period was from January 2013 to August 2016 Three different surgeons took part in the HM arm; 1 surgeon in FAL arm All surgeries at the Hashmanis Hospital Patients were followed up 1 month after the procedure to evaluate for: Visual Acuity using the Snellen chart Refraction using objective and subjective techniques

Results: Preoperative Measurements We found no statistically significant difference in preoperative parameters. Table 1: Preoperative Data   Variable Hansatome Microkeratome (n=1137*) Femto-Assisted Laser (n=229*) P-value Age (Years) 25.0 ± 5.8 (18.0 to 50.0) 27.0 ± 7.3 (18.0 to 52.0) Gender, eyes (M/F) 474/663 72/157 Sphere (D) -4.3 ± 2.8 (-19.0 to 7.0) -4.3 ± 2.3 (-9.8 to 6.8) 0.656 Cylinder (D) -1.0 ± 1.0 (-6.0 to 5.0) -1.0 ± 1.3 (-12.8 to 3.3) 0.713 Spherical Equivalent (D) -4.5 ± 2.8 (-19.5 to 8.0) -4.5 ± 2.5 (-13.4 to 8.0) 0.977 * = Number of eyes Abbreviations: D, diopters; SE, Spherical Equivalent

Results: Postoperative Measurements All postoperative outcomes were statistically significant. Table 2: Postoperative Data Variable Hansatome Microkeratome (n=1137*) Femto-Assisted Laser (n=229*) P-value Sphere (D) 0.0 ± 1.28 (-10.8 to 6.8) 0.3 ± 0.7 (-5.5 to 1.8) <0.001 Cylinder (D) -0.5 ± 0.5 (-4.5 to 1.5) -0.5 ± 0.6 (-5.0 to 1.0) Spherical Equivalent (D) -0.3 ± 1.3 (-11.6 to 6.8) 0.0 ± 0.7 (-6.0 to 1.6) Notes: * = Number of eyes Abbreviations: D, diopters; SE, Spherical Equivalent 

Results: Efficacy (Visual Acuity) We yielded a efficacy index of 1.00 for the FAL arm. The HM arm yielded a lower 0.84 efficacy index.

Results: Astigmatism

Results: Predictability Predictability index of the FAL arm: 92.1 percent Predictability index of the HM arm: 82.2 percent

Results: Spherical Equivalent

Results: Patient Satisfaction 93.3 percent were satisfied with the FAL. 91.4 percent were satisfied with HM.

Limitations This was a retrospective analysis We could not measure higher order aberrations (HOA) We could not measure contrast sensitivity We only had 1 month follow up

Conclusion We found superior outcomes in the FAL arm in almost all areas. Patients were satisfied more with the FAL arm despite its significantly higher cost.

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