Abstract
Purpose :
Reduced accuracy of intraocular lens (IOL) power calculation in eyes with previous corneal refractive surgery is a clinical challenge. Many studies report single surgeon outcomes, and 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 IOL Master Haigis-L formula in patients who have had previous myopic or hyperopic LASIK or PRK.
Methods :
Retrospective case series of all patients with previous refractive surgery who had uneventful phacoemulsification surgery with IOL power calculation using the IOL Master 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. Mean patient age was 63 ± 9.7 years. 58248 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. Comparison to the average IOL power recommended by the ASCRS online calculator for myopic eyes showed a higher IOL power was selected.
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. Using the ASCRS IOL calculator in myopic laser eyes would give less myopic outcomes. The hyperopic Haigis-L algorithm demonstrated accuracy in predicting and achieving target outcomes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.