Comparison of current IOL power calculation methodologies

Session Details

Session Title: IOL Power Calculations, Post-LASIK & Extreme Eyes

Session Date/Time: Tuesday 25/09/2018 | 14:00-16:00

Paper Time: 14:00

Venue: Room A2

First Author: : B.Feijoo PORTUGAL

Co Author(s): :    F. Ribeiro   T. Ferreira   L. Zabala   P. Guerra   C. Goncalves   J. Couceiro     

Abstract Details

Purpose:

To evaluate the accuracy of 6 intraocular lens (IOL) calculation methodologies: SRK-T, Barret Universal II, Ladas Superformula, PhacoOptics, RBF and Panacea.

Setting:

Department of Ophthalmology, Hospital da Luz Lisboa, Portugal

Methods:

Retrospective case series comparison. We enrolled 188 eyes. All of them had had routine ocular examination and optic biometry (Lenstar) preoperatively and then underwent phacoemulsification with implantation of a monofocal IOL. We compared the postoperative residual subjective spherical equivalent with the predicted refractive outcome using each methodology. We also used a Montecarlo pseudo-population with infrequent combinations of biometric parameters for predicting IOL power.

Results:

The mean absolute error (MAE) ranged 0.25D-0.31D with the different methodologies. RBF with the lowest MAE was significantly different from Superformula. All strategies achieved greater than 70,7% of eyes within ± 0,50 D of intended refraction. Hill-RBF provided the lowest MAE in short (< 22 mm) and long eyes (>24.5 mm), and Barret in average eyes (22-24,5 mm). In long eyes we found statistically significant differences between Hill-RBF and Superformula and between PhacoOptics and Superformula. In Montecarlo analysis the range of variation in IOL power calculation tend to be wider, with 1,00 D difference in more than 50% of cases.

Conclusions:

All methodologies provided acceptable results enabling a refractive outcome within ± 1,00 D of intended refraction in 93% of cases. Hill-RBF showed the lowest MAE in our sample, but only statistically different from Ladas Superformula. Currently, because there is not a single methodology that can be used in all cases, only a customized approach incorporating the newer technologies and formulas will enable better refractive results.

Financial Disclosure:

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