Posters

Comparison of corneal biomechanical changes between small incision lenticule extraction and laser assisted in situ keratomileusis using ocular response analyser and the CorVis ST machines

Poster Details

First Author: M.Abdalla EGYPT

Co Author(s):    O. Ibrahim   I. Osman           

Abstract Details

Purpose:

Comparing corneal biomechanical properties of femtosecond small incision lenticule extraction (SMILE) versus laser assisted in situ keratomileusis (LASIK) using the Ocular Response Analyser and the CorVis ST.

Setting:

Roayah Vision Correction Center, Alexandria, Egypt & International femto LASIK center Cairo

Methods:

Fifty eyes equally divided into two groups; Group I included eyes that underwent SMILE procedures using VisuMax® 500 kHz laser system (Carl Zeiss Meditec, Jena, Germany) and Group II included eyes that underwent LASIK procedures using the EX500 Allegretto excimer laser platform (WaveLight GmbH, Erlangen, Germany)& Moria SBK microkeratome. The Ocular Response Analyser (ORA) and the CorVis (CST) measured the corneal biomechanical changes before and after surgeries.

Results:

A statistically significant increase in deformation amplitude occurred following LASIK of 18.8% ±3 and on the contrary the smile group showed an increase of 5.3%±2. A weak correlation was found between postoperative decrease in deformation amplitude and the parameters examined.Corneal hysteresis decreased following LASIK is much more significant in comparison with the smile group. Postoperative reduction in hysteresis did not correlate with the amount or percentage of corneal tissue removed, nor with optical zone or patient age.

Conclusions:

Both LASIK and SMILE substantially decreased the corneal biomechanical properties with greater reduction in the LASIK group. FINANCIAL DISCLOUSRE: One or more of the authors receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented