ESCRS - PP06.11 - Lasik Flap Visual Outcomes And Thickness Comparison Between A New Femtosecond Laser And Ifs

Lasik Flap Visual Outcomes And Thickness Comparison Between A New Femtosecond Laser And Ifs

Published 2022 - 40th Congress of the ESCRS

Reference: PP06.11 | Type: Free paper | DOI: 10.82333/31dz-x269

Authors: Mahipal Singh Sachdev* 1 , Brian Schwam 2 , Ritika Sachdev 1 , Raghav Malik 1 , Michal Laron 3 , Andrew Voorhees 4 , Hong Fu 3 , Ying Wang 3 , Luis Vargas 5

1Cataract & Refractive Surgery,Centre For Sight,New Delhi,India, 2Johnson & Johnson Surgical Vision,Jacksonville,United States, 3Johnson & Johnson Surgical Vision,Milpitas,United States, 4Johnson & Johnson Surgical Vision,Milpitas,India, 5Johnson & Johnson Surgical Vision,Irvine,United States

Purpose

To evaluate the flap thickness and visual outcomes for Laser In-situ Keratomileusis (LASIK) with a new femtosecond (FS) laser compared to iFS. 

Setting

This clinical trial is part of a new FS laser development project and is performed at 2 clinical sites in India. This is a randomized, single arm, contra-lateral, prospective treatment study.

Methods

A prospective, multicenter, open-label, randomized clinical study was performed in 87 subjects scheduled for LASIK.  For each subject, flap creation was randomized using a new FS laser on one eye and iFS on the fellow eye. Mean baseline MRSE was -3.61±1.99 D for the new FS laser and -3.66±1.94 D for iFS group.  UCVA, MRSE and anterior segment Optical Coherence Tomography (OCT) measurements (3 images on each eye) were obtained at 1-week, 1-month, and 3-months after LASIK.  All flaps were planned to 110 µm, and comparison of average achieved flap thickness and standard deviation (SD) was done between the two groups. Correlations between baseline corneal pachymetry and mean keratometry values and flap thickness were also evaluated. 

Results

Mean MRSE was similar and within ±0.25 D for both groups at all post-op visits. UCVA was 20/20 or better in 82.8% of eyes at 1-week and 96.5% at 3-months in both groups. 

Mean achieved flap thickness using the new FS laser was 109.7 µm (±5.0 SD), 111.3 µm (±5.3), and 112.4 µm (±7.5 SD) at 1-week, 1-month, and 3-months, respectively. Mean achieved flap thickness using iFS was 120.9 µm (±5.6 SD), 123.3 µm (±6.0), and 123.5 µm (±7.1 SD) at the same time points (paired t-test <0.0001 at all visits). Variability was similar. No association was found between baseline corneal thickness or mean keratometry and achieved flap thickness based on regression models with non-significant p-values at all time points.

Conclusions

Early feasibility of a new femtosecond laser demonstrates excellent visual outcomes and accuracy when creating flaps for LASIK, at least comparable to the iFS. Both systems were able to achieve consistent flap thicknesses with similar variability.