Outcomes of the Haigis-L formula for calculating intraocular lens power after myopic and hyperopic laser refractive surgery in a tertiary teaching hospital

Session Details

Session Title: IOL Power Calculations

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

Paper Time: 16:48

Venue: Hall C2

First Author: : C.da Costa Paula UK

Co Author(s): :    Y. Shweikh   R. Deshmukh   M. Restori   V. Saw           

Abstract Details

Purpose:

Reduced accuracy of intraocular lens (IOL) power calculation in eyes with previous corneal refractive surgery is a clinical challenge. Online calculators and several formulae including the Haigis-L formula have been developed to facilitate accurate IOL power selection following laser vision correction. In comparison to available data on outcomes in eyes with previous myopic laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK), there is limited data on outcomes of the Haigis-L hyperopic formula. In this study we report outcomes from a tertiary teaching hospital using the Haigis-L formula in patients who have had previous myopic or hyperopic LASIK or PRK.

Setting:

Moorfields Eye Hospital, London, UK

Methods:

Retrospective case series of all patients with previous myopic or hyperopic refractive surgery (LASIK or PRK) who had uneventful phacoemulsification surgery with IOL power calculation using the Haigis-L formula at Moorfields Eye Hospital between January 2012 and April 2015. Exclusion criteria were complicated surgery, coexisting conditions potentially confounding the refraction, lack of information about myopic vs hyperopic surgery, and implantation of a multifocal or toric IOL. Statistical analysis: mean values were compared using the Student t test if normally distributed. The Fisher chi-square test was used to analyze proportions. P values were 2 sided with significance of less than 0.05.

Results:

63 eyes (44 patients) were analysed. 48 eyes (76%) had previous myopic laser surgery; 42/48 eyes (87.5%) had axial lengths >25.0mm. 15 eyes (24%) had previous hyperopic laser. For myopic Haigis-L, the mean arithmetic prediction (MAPD) error was -0.58 D  1.46 and the mean absolute (MA) error was 1.2 D  1.01. For hyperopic Haigis-L, the MAPD error was 0.07 D  0.84 D and the MA error was 0.67 D  0.47. Predictability of being within 0.50 D and 1.00 D of target was 25.0% and 52.1% for myopic eyes, and 33.3% and 66.7 % for hyperopic eyes.

Conclusions:

The arithmetic prediction error for myopic Haigis-L in this study is larger than previously described, but close to that reported in eyes with axial length >25mm. The hyperopic Haigis-L algorithm demonstrated accuracy in predicting and achieving target outcomes.

Financial Disclosure:

NONE