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Related Experiment Video

Updated: Jun 27, 2026

Synthesis of Soft Polysiloxane-urea Elastomers for Intraocular Lens Application

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Published on: March 8, 2019

Simplification of a Three-Constant Intraocular Lens Calculation Formula to a Single-Constant Approach: The Haigis

Achim Langenbucher¹, Nóra Szentmáry^1,2, Alan Cayless³

¹Department of Experimental Ophthalmology, Saarland University, 66424 Homburg, Germany.

Diagnostics (Basel, Switzerland)

|June 26, 2026

Summary

This summary is machine-generated.

A simplified Haigis intraocular lens (IOL) formula with a single constant and optimized keratometer index maintains prediction accuracy. This modification aids clinical implementation for better refractive outcomes.

Keywords:

Haigis formula biometry cataract surgery formula optimization intraocular lens

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Automated Compression Testing of the Ocular Lens

Published on: April 5, 2024

Area of Science:

Ophthalmology
Biomedical Engineering
Optical Engineering

Background:

The Haigis formula is a widely used method for intraocular lens (IOL) power calculation.
It utilizes a three-constant effective lens position (ELP) model.
Simplification could improve clinical utility and accuracy.

Purpose of the Study:

To develop and validate a simplified Haigis IOL power calculation formula.
The modification aims to reduce the ELP model to a single constant.
Inclusion of an optimized keratometer index and axial length correction is proposed.

Main Methods:

Retrospective analysis of a large multicentric dataset (Dataset 1: 22,466 eyes, 113 IOL models).
Optimization of Haigis constants and keratometer index using nonlinear programming with Cooke's axial length correction.
Cross-validation on an independent dataset (Dataset 2: 3181 eyes, 6 IOL models) comparing classical Haigis, modified triplet, and two single-constant models (H1, H2).

Main Results:

An optimized keratometer index (1.3296 ± 0.0003) was derived, significantly lower than the classical value.
Single-constant models (H1 and H2) demonstrated comparable or reduced prediction errors versus the classical Haigis formula.
The H1 approach (single constant acting on IOL power) showed marginally superior performance; parameter stability was confirmed via bootstrapping.

Conclusions:

A single-constant modification of the Haigis formula is feasible.
Incorporating an optimized keratometer index and axial length correction maintains prediction accuracy.
The simplified formula offers easier clinical implementation for intraocular lens power calculation.