Lens meridian position as a predictor of effective lens position

Abstract

Purpose : This study produced a statistical model to predict the post-operative effective lens position (ELP) based upon pre-operative measurements of the lens meridian position (LMP) in patients undergoing femtosecond laser-assisted cataract surgery (FLACS).

Methods : This was a retrospective chart review of 104 eyes (51 right, 53 left) from 62 patients that underwent FLACS with one of four surgeons at the University of California, Irvine between July 2015 and August 2016. Inclusion criteria were completion of FLACS in at least one eye. Exclusion criteria included prior refractive surgery or vitrectomy. Pre-operative anatomic parameters were measured using the Catalys® Precision Laser System (Abbott Medical Optics, Santa Ana, CA) and the IOLMaster® 500 by Carl Zeiss Meditec (Germany). Post-operative anatomic parameters were measured using the Pentacam® by Oculus (Germany). Data analysis and visualization was performed in Microsoft Excel and R Studio.

Results : The fractional meridian position (FMP), a variable characterized in our previous work, is defined as the fraction of the total lens thickness that lies anterior to the lens meridian. A new variable, the fractional effective lens position (FELP) has now been defined as the fraction of the pre-operative lens thickness that lies anterior to the eventual effective lens position. Using a multiple linear regression model and ANOVA analysis, we have demonstrated that the FMP is the only independent pre-operative biometric variable capable of predicting the FELP in a statistically significant manner (intercept -0.28, coefficient 1.58, P = .00004). No other variable in our broad biometric analysis reached statistical significance in predicting the FELP.

Conclusions : Our latest study has demonstrated that the lens meridian position is a powerful new variable in predicting the post-operative effective lens position, which holds the potential to significantly refine the accuracy of pre-operative lens power calculations.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.