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Comparison of visual outcomes after correcting myopia using the variable spot scanning refractive procedure versus the wavefront optimized procedure

Poster Details

First Author: M.Khalifa EGYPT

Co Author(s):    E. Mosallam              

Abstract Details


Compare effectiveness of variable spot scanning (VSS) Refractive ablation versus wavefront optimized ablation (WFO) for the correction of spherical and sphero-cylindrical myopia.


Horus Vision Correction Center & Alex Eye Center, Alexandria, Egypt.


A prospective consecutive comparative multicentre masked study of 2 groups, each 50 eyes of myopia with or without astigmatism. Both groups had LASIK using M2 microkeratome (MORIA). VSS group was treated with VSS Refractive ablation with Star S4IR excimer laser (AMO) and WFO group was treated with wavefront-optimized ablation with Allegretto Eye-Q excimer laser (Alcon). Visual outcome was evaluated preoperatively and 3 months after surgery including contrast sensitivity (CS) with the CVS-1000 (Vector Vision) and HOA's with the Wave Scan aberrometer (AMO).


Mean pre and postop. SE in VSS gp were - 3.8 (±1.98) and -0.14 (± 0.2), and in WFO gp -4.03 (±2.25) and -0.15 (± 0.28) without significant difference between groups. After 3 months, no significant difference between groups in UCVA (P=0.465), BCVA (P=0.416), and SE (P=0.303). Efficacy and safety indices were 105 and 110 in VSS, and 101 and 106 in WFO. Attempted vs. achieved correlation of SE was r= 0.966 in VSS and r= 0.9656 in WFO. Mean induced +ve SA was 0.041 µm (P=0.00) in VSS and 0.195 µm (P=0.00) in WFO with significant difference between 2 gps (P=0.000).


VSS refractive and wavefront optimized ablations are equally effective, safe, and predictable in treating myopia with or without astigmatism. Both ablations induced minimal but significant positive spherical aberration, which was significantly higher with wavefront optimized ablation than with VSS ablation. FINANCIAL INTEREST: One of more of the authors... research is funded, fully or partially, by a company producing, developing or supplying the product or procedure presented

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