Prediction of refractive outcomes with toric intraocular lens implantation

Abstract

Purpose: To evaluate and compare the accuracy of different methods to measure and predict postoperative astigmatism with toric intraocular lens (IOL) implantation.

Setting: Ein-Tal Ophthalmology Center, Tel-Aviv, Israel.

Design: Retrospective case series.

Methods: Postoperative corneal astigmatism was measured with 3 devices (IOLMaster 500; optical low-coherence reflectometry [OLCR]-based Lenstar LS 900; Atlas topographer) and compared with the manifest astigmatic refractive outcome in patients with toric IOLs. The error in the predicted residual astigmatism was calculated by vector analysis according to the measurement and calculation method used to predict the required toric IOL cylinder power.

Results: The centroid errors in predicted residual astigmatism were against the rule with the Alcon and Holladay toric calculators (0.53 to 0.56 diopter [D]), were lower with the Baylor nomogram (0.21 to 0.26 D), and were lowest for the Barrett toric calculator (0.01 to 0.16 D) (P <.001). The Barrett toric calculator had the lowest median absolute error in predicted residual astigmatism (0.35 to 0.54 D, all devices) compared with the Alcon and Holladay toric calculators with or without the Baylor nomogram (P <.021). The Barrett toric calculator and the OLCR device achieved the most accurate results; 75.0% and 97.1% of eyes were within ±0.50 D and ±0.75 D of the predicted residual astigmatism, respectively.

Conclusion: Prediction of astigmatic outcomes with toric IOLs can be improved with appropriate measuring devices and methods to establish the required toric IOL power.