Eye models for the prediction of contrast vision in patients with new intraocular lens designs.

Theoretical calculations of the polychromatic modulation transfer function (MTF) and wave-front aberration were performed with physiological eye models. These eye models have an amount of spherical aberration that is representative of a normal population of pseudophakic eyes implanted with two different types of intraocular lens (IOL) made from high-refractive-index silicone. These theoretical calculations were compared with the measured contrast sensitivity function (CSF) under mesopic lighting conditions and with wave-front aberration (obtained with a Hartmann-Shack wave-front sensor) collected from 37 patients bilaterally implanted with the same types of lens.

A new intraocular lens design to reduce spherical aberration of pseudophakic eyes.

Purpose: The aim of this study was to design and evaluate in the laboratory a new intraocular lens (IOL) intended to provide superior ocular optical quality by reducing spherical aberration.

Methods: Corneal topography measurements were performed on 71 cataract patients using an Orbscan I. The measured corneal surface shapes were used to determine the wavefront aberration of each cornea.

Determining the imaging quality of intraocular lenses.

Purpose: To validate the proposed optical requirements of a draft international standard for intraocular lenses (IOLs).

Setting: Eight optical testing laboratories in the United States, Germany, Japan, and The Netherlands.

Methods: The testing laboratories performed modulation transfer function (MTF) tests on various IOLs using a model eye and visual resolution tests in air.

Prediction of intraocular lens power using the lens haptic plane concept.

Purpose: To test algorithms for the preoperative estimation of the lens haptic plane (LHP) and to assess these in terms of predictability of postoperative refraction.

Setting: S:t Erik's Eye Hospital, Stockholm, Sweden.

Methods: Preoperative axial length, anterior chamber depth (ACD), and cataractous lens thickness were measured in consecutive cases scheduled for phacoemulsification and posterior chamber intraocular lens (IOL) implantation.

Accuracy in determining intraocular lens dioptric power assessed by interlaboratory tests.

Purpose: To describe a testing program conducted by a standards group as a guide for setting international tolerances for intraocular lens (IOL) dioptric power.

Setting: Multicenter study.

Methods: Seven biconvex, poly(methyl methacrylate) IOLs ranging in power from 10.

Standardized methods for assessing the imaging quality of intraocular lenses.

The relative merits of three standardized methods for assessing the imaging quality of intraocular lenses are discussed based on theoretical modulation-transfer-function calculations. The standards are ANSI Z80.7 1984 from the American National Standards Institute, now superseded by ANSI Z80.