Accuracy of the new IOL power calculation formulas in eyes with long axial length

Session Details

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

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

Paper Time: 15:22

Venue: Room A2

First Author: : J.Coelho PORTUGAL

Co Author(s): :    C. Abreu   P. Baptista   M. Lume   R. Salgado   P. Meneres   M. Brochado     

Abstract Details

Purpose:

To compare the accuracy of the newer intraocular lens (IOL) power calculation formulas in eyes with axial length (AL) superior to 26 mm.

Setting:

Department of Ophthalmology of a tertiary referral centre in Oporto, Portugal - Centro Hospitalar Universitario do Porto

Methods:

Retrospective chart review of patients who underwent cataract surgery with IOL implantation from January to December 2017. Inclusion criteria were an AL superior to 26 mm, availability of preoperative AL, preoperative ACD data, 1-month postoperative refraction data and uneventful surgery. AL, corneal power and anterior chamber depth (ACD) were measured with IOL Master. Third generation formulas (Hoffer Q, SRK/T and Holladay) and fourth generation formula (Haigis, Barrett Universal II and Hill-RBF) were used to predict IOL powers. The predictive accuracy of the formulas was analysed by comparison of the mean error (ME) and the mean absolute error (MAE).

Results:

Seventy-four eyes (48 patients) were included. Mean AL was 28.01±2.01mm. Mean postoperative spherical equivalent was -0.76±0.76 diopters. ME and MAE from the Barrett formula were the smallest (-0.165±0.574 and 0.416±0.426) followed by the Hill-RBF formula, ME and MAE from the Hoffer Q formula were the largest (-0.754±0.763 and 0.790±0.725, respectively). Difference in ME and MAE between formulas was significant (P<0.0001). All third-generation formulas presented statistically significant differences in MAE between the group with AL between 26 and 29mm and the group with AL>29mm, with better results in the smaller AL group. In eyes with AL>29mm, Barret presented the smallest MAE.

Conclusions:

IOL power prediction may be inaccurate in high myopic patients. In our study, the Barrett Universal II formula and the Hill-RBF formula produced more accurate results in high myopic eyes. In eyes with AL superior to 29 mm the refractive results are even less predictable however fourth generation formulas, Barret Universal II formula followed by Hill-RBF formula, presented smallest ME and MAE.

Financial Disclosure:

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