# Optimizing axial length estimation for intraocular lens power calculation in phacovitrectomy for macula-off retinal detachment

## TL;DR

This study compares methods to estimate eye length for lens calculations in retinal detachment surgery, finding a simple algorithm and fellow eye measurements to be reliable.

## Contribution

The study introduces and evaluates novel decision algorithms for axial length estimation in a specific surgical context.

## Key findings

- The simple algorithm achieved the lowest mean absolute prediction error (0.31 ± 0.55 mm) for axial length estimation.
- The fellow eye's axial length measured via IOL Master provided a reliable alternative when the affected eye's measurement was not feasible.
- Bland-Altman analysis showed good agreement between preoperative and postoperative axial length measurements using the IOL Master.

## Abstract

To evaluate methods of preoperative axial length (AL) estimation for intraocular lens (IOL) power calculation in patients with macula-off rhegmatogenous retinal detachment (RRD). These methods included optical biometry, A-scan biometry, and novel decision algorithms.

A retrospective analysis of prospectively collected data was conducted at a tertiary hospital from January 2018 to December 2023. Preoperative and postoperative AL measurements were obtained using optical biometry (IOL Master 700, Zeiss, Germany) and A-scan biometry (VuMAX, Sonomed, USA). The primary outcome was the mean absolute prediction error (MAE) between postoperative AL and preoperative estimates generated by five methods, including two novel algorithms.

The study included 56 patients (56 eyes). The lowest MAE was achieved using the simple algorithm (0.31 ± 0.55 mm), followed by the AL of the fellow eye measured via IOL Master (0.34 ± 0.60 mm), and the advanced algorithm (0.36 ± 0.62 mm). A Kruskal-Wallis H test found no statistically significant difference in MAE across the five methods (P = 0.118). Bland-Altman analysis demonstrated good agreement between preoperative and postoperative AL measurements obtained with the IOL Master.

For patients undergoing phacovitrectomy for macula-off RRD, the simple algorithm provides accurate AL estimation for IOL power calculation. In cases where AL measurement of the affected eye is not feasible using the IOL Master, the fellow eye’s AL is a reliable alternative.