Posters

Accuracy of IOL power calculations for monovision

Poster Details

First Author: A.Turnbull UK

Co Author(s):    W. Hill   G. Barrett                 

Abstract Details

Purpose:

To investigate the accuracy of intraocular lens (IOL) power calculation methods when targeting myopia compared with emmetropia, in the context of monovision.

Setting:

Lions Eye Institute, Perth, Australia

Methods:

88 consecutive patients undergoing bilateral, sequential cataract surgery with a plan of modest monovision were analyzed. Target refraction was approximately plano (distance eye) and -1.25D (near eye). Prediction error was determined by comparing the actual postoperative refraction with the predicted postoperative refraction, calculated by the Barrett Universal II (BUII), Hill-RBF version 2.0 (Hill-RBF 2.0), Haigis, Holladay I, SRK/T and Hoffer Q formulae. The dataset was divided into distance and near eye subgroups. Mean and median absolute error (MAE; MedAE), and percentage of eyes within +/-0.25, +/-0.50, +/-0.75 and +/-1.00D of refractive target was compared.

Results:

There was a consistent trend for lower refractive accuracy in the eyes targeted for near. BUII and Hill-RBF 2.0 were the most accurate overall and least affected by this phenomenon, with 1.1% and 4.6% fewer eyes respectively in the near subgroup achieving +/-0.50D of target. Haigis and SRK/T were most affected, with 15.9% and 12.5% fewer near eyes achieving +/-0.50D of target (p <0.05). Holladay I and Hoffer Q occupied the middle ground, with 6.8% and 10.2% fewer near eyes achieving +/-0.50D of target.

Conclusions:

IOL-power calculation formulae appear to be less accurate when targeting myopia compared with emmetropia. BUII and Hill-RBF 2.0 represent good options when planning pseudophakic monovision as they are least affected by this phenomenon and can be used for both distance and near eyes.

Financial Disclosure:

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