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Accuracy of toric IOL power calculation using Haigis-T formula with standard K-readings compared to new true keratometry measurement using posterior cornea surface curvature

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Session Details

Session Title: Pseudophakic IOLs: Toric, Multifocal, Accommodative

Session Date/Time: Monday 09/10/2017 | 14:30-16:00

Paper Time: 15:46

Venue: Room 4.1

First Author: : E.Fabian GERMANY

Co Author(s): :                        

Abstract Details


To compare post-operative refractive outcomes of toric IOL calculation based on measured anterior and posterior corneal surface curvature. True Keratometry (TK) of the IOLMaster 700 to classic methods using telecentric one-zone (1z) keratometry as well as telecentric 3-zone (3z) keratometry of the IOLMaster 700, accounting for anterior corneal curvature only were used.


Augen Centrum Rosenheim, Germany.


IOL power calculation (Haigis-T), cataract surgery and IOL-Implantation (ZEISS CT Asphina 409 M) were performed in 32 eyes using clinic’s standard pre-, intra- and post-operative clinical procedures. Cylinder (cyl) and spherical equivalent (SEQ) post-op refractive outcome was assessed by manifest refraction at a minimum of 8 week after surgery. Additionally, raw data were collected using an export function available in the device software (IOLMaster 700) pre- and at least 6 weeks post-surgery. Internal prototype software (Carl Zeiss Meditec AG) was applied to generate TK power values from pre- and post-surgical data including anterior and posterior surfaces of the cornea.


Results present preliminary prediction errors for 32 cases. Further data collection is ongoing and more data will be presented. Mean absolute Haigis-T error for SEQ was 0.36D +/- 0.3D with 1z keratometry; 0.34D +/- 0.28D with 3z keratometry and 0.30D +/- 0.26D with TK. Mean absolute error of CYL was 0.70D +/- 0.39D; 0.62D +/- 0.28D and 0.46D +/-0.26D respectively.


The IOLMaster 700 True Keratometry values, based on anterior and posterior corneal surface curvatures, show favourable results for CYL and SEQ outcome performance when compared to classic anterior corneal surface keratometry.

Financial Disclosure:

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

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