Evaluating the refractive outcome of a standard industry calculator for toric intraocular lens calculation

Session Details

Session Title: Toric IOL Calculations & Alignment

Session Date/Time: Sunday 23/09/2018 | 08:00-10:00

Paper Time: 08:24

Venue: Room A5

First Author: : C.Kern GERMANY

Co Author(s): :    L. El Kaissi   K. Kortuem   M. Shajari   S. Priglinger   W. Mayer        

Abstract Details

Purpose:

To analyze astigmatic prediction errors (APE) for four different calculation methods and to evaluate the influence of posterior corneal astigmatism (PCA) for toric intraocular lens calculation.

Setting:

Ongoing prospective case series, University Eye Hospital (Ludwig Maximilan University), Munich, Germany

Methods:

We determined the refractive outcome for 37 eyes with cataract and regular astigmatism >1.0D undergoing cataract extraction followed by implantation of a toric IOL (Zeiss Torbi 709 M) calculated by the Zeiss toric calculator (ZCalc). All patients received pre- and postoperative assessment including Keratometry (IOL-Master700), corneal tomography (Pentacam) and manifest refraction. APE was calculated for four different calculation methods: ZCalc, Haigis toric suite, Barrett toric calculator and for ZCalc using total corneal refractive power (TCRP) measurements. All APE calculations were performed by vector analysis.

Results:

For ZCalc we observed a refractive prediction error of the spherical equivalent of 0.18 ± 0.42 D (p=0.16) and a mean absolute error of 0.11 D after lens constant optimization. The percentage of eyes within a certain range of refractive prediction error was 43% within ± 0.25D, 74% within ± 0.50D and 100% within ± 1.00D. Right now, we are evaluating the APE by vector analysis to compare the four different calculation methods (ZCalc, Haigis toric suite, Barret calculator and ZCalc including TCRP values). Results will be presented on the congress.

Conclusions:

Using the Zcalc for toric IOL calculation is a safe method to achieve accurate postoperative refractive outcomes with most eyes within a refractive prediction error range of ±0.5D. A slight undercorrection of 0.18 D has been observed in all eyes.

Financial Disclosure:

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