Posters

Comparison of the accuracy of 2 IOL power calculation formulae using total keratometry

Poster Details

First Author: A.Abdul Hamid UK

Co Author(s):                        

Abstract Details

Purpose:

The purpose of the study was conducted to evaluate and compare the accuracy of the refractive prediction determined by the calculation formulas for different intraocular lens (IOL) powers for patients undergoing refractive lens exchange with a non toric trifocal IOL.

Setting:

Optegra Eye Hospital, London

Methods:

This study reviewed 200 eyes from 100 patients who underwent refractive lens exchange and IOL implantation. The refractive mean numerical error (MNE) and mean absolute error (MAE) of the IOL power calculation formulas Z Calc (CZM, Jena) and Barrett Universal II in conjunction with Total Keratometry (TK) using the IOLMaster 700 (CZM, Jena) were examined and compared. The MNE and MAE at different axial lengths (AL) were compared, and the percentage of every refractive error absolute value for each formula was calculated at ±0.25D, ±0.50D and ±1.00D.

Results:

We found the results from the 2 Formulae comparable. For Z Calc 44 % of eyes were within +/- 0.25 D, 84% within +/-0.5D and 100% within +/-1.00D respectively. For Barret Universal II the results were 46%, 85% and 100% respectively. The MNE was -0.30 fro Z Calc and -0.33 for Barrett II. The MAE was 0.47 and 0.5 respectively. There were no statistically significant difference between the 2 groups.

Conclusions:

Both Z Calc and Barrett Universal II used with TK yield very accurate IOL power calculations and can be used interchangeably if required.

Financial Disclosure:

receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented