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Effect of repeatability and increments of automated keratometry on astigmatism correction with toric intraocular lens
Session Title: Intraoperative Biometry and Correction of Astigmatism
Session Date/Time: Monday 07/10/2013 | 08:00-10:00
Paper Time: 09:51
Venue: Main Lecture Hall (Ground Floor)
First Author: : Y.Ninomiya JAPAN
Co Author(s): : Y. Kanazawa Y. Kojima N. Maeda
To discuss repeatability and scale increments of automated keratometry and their influence on the usage of the toric intraocular lens (IOL) and on astigmatism correction.
Yukioka Hospital, Osaka, Japan
The study enrolled 131 eyes of 82 patients. Preoperative corneal astigmatism was measured in the different (0.01D and 0.25D) scale increment setting of automated keratometer (KR-8800, Topcon Corp, Tokyo, Japan) on separate days. An arithmetic astigmatism in 0.25D scale increment was also calculated from that of 0.01D scale increment. These three types of corneal astigmatism were comparatively evaluated by the results of the web-based calculator (http://www.acrysoftoriccalculator.com/), such as indication and style selection of toric IOL (AcrySof IQ Toric IOL, Alcon Laboratories, Inc) and simulated residual astigmatism.
Different scale increments caused no significant difference of simulated residual astigmatism. The repeatability of calculated IOL selection and axis location was low in eyes with a small amount of astigmatism. True standard deviation of test-retest discrepancy in the size of corneal astigmatism was 0.293D.
The effectuation of the toric IOL was simulated to diverge in case of small astigmatism. Still, the scale increment of 0.25D presented moderate sensitivity. The nomogram is expected for more precise astigmatism correction with toric IOL implantation.
... research is funded, fully or partially, by a company producing, developing or supplying the product or procedure presented