# Surgical Volume for Intraocular Lens (IOL) Dislocation/Decentration and Associated Patient/Ocular Factors: A Retrospective Multicenter Study in Japan

## TL;DR

This study analyzed trends in intraocular lens surgeries and related factors in Japan from 2008 to 2014.

## Contribution

The study provides new insights into the increasing surgical volume for IOL dislocation and highlights training needs for complex IOL procedures.

## Key findings

- The number of routine cataract surgeries increased significantly from 2008 to 2014.
- Surgeries for IOL dislocation also increased significantly, while surgeries for IOL decentration and aphakia remained stable.
- Comorbidities like diabetes and uveitis did not show significant changes over the study period.

## Abstract

Purpose

This study aimed to analyze temporal changes in the number of surgeries performed for intraocular lens (IOL) dislocation/decentration and aphakia and to examine the associated patient and ocular background factors across three institutions.

Methods

We conducted a retrospective review of all cataract-related procedures performed between January 1, 2008, and December 31, 2014, at Nagoya University Hospital, Sugita Eye Hospital, and Miyake Eye Hospital. We quantified (1) the annual number of standard cataract surgeries (routine lens extraction with IOL implantation), (2) the annual number of IOL fixation procedures for aphakic eyes (including scleral fixation), and (3) the annual number of surgeries specifically for IOL dislocation/decentration (IOL explantation and/or IOL refixation including scleral fixation). Cases involving IOL fixation within three months after the primary cataract surgery were excluded from the IOL dislocation cohort. We also assessed the presence of diabetes, pseudoexfoliation (PEX), atopic dermatitis (AD), uveitis, and prior vitrectomy. Age and sex were also recorded. Institutional review board approvals were obtained at all three sites.

Results

The annual number of routine cataract surgeries increased significantly from 6,307 in 2008 to 8,469 in 2014 (p<0.01). Surgeries for IOL dislocation also showed a significant increase over the same period (p<0.01). In contrast, there was no significant trend in the annual number of IOL fixations for aphakia (p=0.73) or surgeries for IOL decentration (p=0.94). After Bonferroni correction, the proportions of comorbidities, including diabetes, uveitis, and prior vitrectomy, showed no significant change over time. The mean age of patients and the male-to-female ratio also remained stable throughout the study period.

Conclusions

While the volume of routine cataract surgery and procedures for IOL dislocation significantly increased, the surgical load for secondary IOL fixation in aphakic eyes remained constant. Given Japan's rapidly ageing population, there is an expected increase in the need to train surgeons who are proficient in IOL fixation, including scleral fixation.