Area Under the Modular Transfer Function Curve Does Not Predict Convolved E Image Quality

Abstract

Purpose: : The purpose of this analysis was to examine and relate the area under the curve modular transfer function (MTF) values and convolved E image quality for a set of intraocular lens designs.

Methods: : A series of intraocular lens (IOL) designs representing single vision spherical and aspheric lenses were modeled in Zemax^TM. The Zemax^TM model consisted of a 43 D paraxial cornea and the IOL. The intraocular lens designs all used commonly used optical surfaces that could be lathed or molded using current technology. A set of area under the curve MTF values were recorded for different object positions, and related to convolved single letter images representing a 20/20 Snellen letter. Observers subjectively ranked the convolved E’s on a scale of 1 to 3 with 1 being best image quality.

Results: : Image quality for the convolved E’s differed noticeably for the series of test designs. The conventional assumption is that a larger area under the curve MTF value indicates better image quality. However, in this standard set of 3 intraocular lenses better E’s as ranked by 3 observers were associated with lower area under the curve MTF values 42% of the times.

Conclusions: : Area under the MTF curve alone is not an absolute predictor of image quality.

Keywords: optical properties • aberrations • intraocular lens