Comparison of visual outcomes after variable spot scanning ablation versus wavefront-optimized myopic LASIK

Area of Science:

• Ophthalmology
• Refractive Surgery

Background:

• Laser-assisted in situ keratomileusis (LASIK) is a common procedure for correcting myopia and myopic astigmatism.
• Advancements in excimer laser technology aim to improve refractive and visual outcomes while minimizing side effects.

Purpose of the Study:

• To compare the refractive and visual results of two distinct LASIK ablation profiles: Variable Spot Scanning (VSS) and Wavefront-Optimized (WFO).
• To evaluate the induction of spherical aberration by each ablation profile.

Main Methods:

• A prospective study involving 100 eyes of 50 myopic patients undergoing LASIK.
• Patients were randomized into two groups: VSS ablation (VISX STAR S4/IR) and WFO ablation (WaveLight Allegretto Wave Eye-Q).
• Outcomes measured included manifest refraction, visual acuity (uncorrected and corrected distance), wavefront analysis, and contrast sensitivity at various postoperative intervals.

Main Results:

• Both VSS and WFO groups achieved comparable mean postoperative spherical equivalent (-0.14 ± 0.2 D for VSS, -0.15 ± 0.28 D for WFO) and visual acuity.
• A high percentage of eyes in both groups were within ±0.5 diopters of the intended correction.
• While both methods induced positive spherical aberration, the WFO group showed a statistically significant higher induction (0.195 ± 0.171 µm) compared to the VSS group (0.041 ± 0.046 µm).

Conclusions:

• Variable Spot Scanning (VSS) and Wavefront-Optimized (WFO) ablation demonstrate similar efficacy and safety in correcting myopia and myopic astigmatism.
• Both ablation profiles induce positive spherical aberration, with WFO resulting in a significantly greater increase.
• The choice of ablation profile may influence the induction of higher-order aberrations, particularly spherical aberration.