Open AccessDetermination of Personalized IOL-Constants for the Haigis Formula under Consideration of Measurement Precision
Author(s) -
Simon Schröder,
Christina Leydolt,
Rupert Menapace,
Timo Eppig,
Achim Langenbucher
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0158988
Subject(s) - mathematics , least squares function approximation , formalism (music) , observational error , inverse , statistics , non linear least squares , intraocular lens , explained sum of squares , algorithm , optics , physics , geometry , art , musical , estimator , visual arts
The capabilities of a weighted least squares approach for the optimization of the intraocular lens (IOL) constants for the Haigis formula are studied in comparison to an ordinary least squares approach. The weights are set to the inverse variances of the effective optical anterior chamber depth. The effect of random measurement noise is simulated 1 times using data from N = 69 cataract patients and the measurement uncertainty of two different biometers. A second, independent data set ( N = 33) is used to show the differences that can be expected between both methods. The weighted least squares formalism reduces the effect of measurement error on the final constants. In more than 64% it will result in a better approximation, if the measurement errors are estimated correctly. The IOL constants can be calculated with higher precision using the weighted least squares method.