Gender differences in intraocular lens power calculation: comparison of 7 formulae in 2849 patients

Session Details

Session Title: IOL Power Calculations

Session Date/Time: Sunday 11/09/2016 | 16:00-18:00

Paper Time: 17:00

Venue: Hall C2

First Author: : J.Kane AUSTRALIA

Co Author(s): :    A. Van Heerden                    

Abstract Details

Purpose:

To assess the effect gender has on the accuracy of the commonly used intraocular lens (IOL) power formulae (Barrett Universal 2, Haigis, Hoffer Q, Holladay 1, Holladay 2, SRK/T and the T2 formula) using optimised lens constants where possible.

Setting:

A large tertiary centre over the past 5 years.

Methods:

Retrospective analysis of patients undergoing cataract surgery over the past 5 years. Pre-operative measurements, operative details and post-operative refraction in patients undergoing uncomplicated cataract surgery were collected. Optimised lens constants for each formula (excluding Barrett Universal 2) were calculated. The optimised lens constants were used to calculate the predicted refractive outcome in each of the 7 formulae and compared to the actual refractive outcome. Analysis was then performed based on patient gender. Sub-analysis was performed based on axial length groups and anterior chamber depth groups.

Results:

Results obtained using only one eye from each study subject are presented. The Barrett Universal 2 formula had a lower mean absolute error (MAE) for males compared with females (0.372 vs 0.397). For the remaining formulae females had a lower MAE than males: Haigis (0.411 vs 0.430), Hoffer Q (0.419 vs 0.435), Holladay 1 (0.403 vs 0.412), Holladay 2 (0.417 vs 0.426), SRK/T (0.410 vs 0.415) and T2 formula (0.405 vs 0.409). The gender differences between formulae became more pronounced at extremes of axial length and anterior chamber depth.

Conclusions:

There exists a difference in the results of the commonly used IOL power formulae based on gender. For all except the Barrett Universal 2 formula females have lower MAE’s than males. The utility of either separate lens constants based on gender, a correction factor for each formula based on gender or a new IOL power formulae using gender as a variable to lower MAE’s requires further investigation.

Financial Disclosure:

NONE