Posters

Total keratometry for determination of true corneal power after myopic small incision lenticule extraction

Poster Details

First Author: N.Luft AUSTRIA

Co Author(s):    R. Lischke   W. Mayer   N. Feucht   J. Siedlecki   R. Wiltfang   D. Kook     

Abstract Details

Purpose:

To gauge the value of total keratometry (TK) to estimate corneal power change in eyes that underwent SMILE for treatment of myopia or myopic astigmatism.

Setting:

Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstraße 8, 80336 Munich, Germany

Methods:

A total of 80 eyes of 40 patients who had undergone myopic SMILE were enrolled in this cross-sectional study. Total corneal refractive power (TCRP; Pentacam HR; Wetzlar, Germany) and TK (IOL Master 700; Carl Zeiss Meditec AG, Jena, Germany) values were compared to the clinical history method (CHM). The surgically induced changes in TCRP (ΔTCRP) and TK (ΔTK) were also compared to the changes in spherical equivalent on the corneal plane (ΔSEco). Additionally, IOL power calculation using two novel formulas specifically developed for TK was theoretically compared with various established formulas optimized for post-keratorefractive surgery eyes.

Results:

The correlation between TK and CHM (R2 = 0.87, p<0.001) was stronger than between TCRP and CHM (R2 = 0.74, p<0.001). As compared with the CHM, TCRP underestimated corneal power by a mean relative error of 0.58 D and TK by 0.25 D. Linear regression analysis of ΔTCRP/ΔTK and the difference between preoperative and postoperative manifest refraction spherical equivalent at the corneal plane (Δ SEco) showed stronger correlation in ΔTK (R2 = 0.87), than in ΔTCRP (R2 = 0.74). One-way analysis of variance (ANOVA) with Bonferroni-corrected post hoc testing revealed that TK based formulas lay at the lower end of the calculated IOL power spectrum.

Conclusions:

The findings endorse TK as an accurate measure for corneal power after myopic SMILE and promise favorable refractive outcomes of IOL power calculation after SMILE using novel TK-dedicated formulas.

Financial Disclosure:

receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented, travel has been funded, fully or partially, by a competing company, receives consulting fees, retainer, or contract payments from a competing company