# Ultrasound biomicroscopy-based quantitative assessment of anterior segment biometric changes in contralateral eyes of unilateral neovascular glaucoma: a retrospective case-control study

## TL;DR

This study uses ultrasound biomicroscopy to detect early structural changes in the unaffected eyes of patients with neovascular glaucoma, especially in the elderly.

## Contribution

The study introduces UBM as a tool for identifying high-risk anterior segment changes in fellow eyes of unilateral neovascular glaucoma patients.

## Key findings

- Fellow eyes showed shallower anterior chambers and narrower angles compared to controls.
- Elderly patients exhibited more pronounced structural differences with strong diagnostic indicators like IC, ACD, and AOD750.
- UBM parameters correlated with age and showed potential for early risk screening.

## Abstract

Neovascular glaucoma (NVG) is a blinding ocular disease secondary to severe retinal ischemic disorders, characterized by rapid progression and severe visual impairment. While most studies focus on diagnosis and intervention of affected eyes in NVG, systematic evaluation of structural status and potential risks in fellow eyes remains insufficient.

This study aims to quantitatively analyze anterior segment structures in fellow eyes of unilateral NVG patients using ultrasound biomicroscopy (UBM), identify differences from normal eyes, and investigate age-related variations in anterior segment parameters along with their diagnostic efficacy.

This retrospective case-control study included fellow eyes of unilateral NVG patients (observation group) and age- and gender-matched normal eyes (control group). UBM-measured parameters included anterior chamber depth (ACD), angle opening distance (AOD500/750), trabecular-iris angle (TIA500/750), iris thickness (IT500/750/2000), iris convexity (IC), trabecular-ciliary process distance (TCPD), and iris-cornea posterior surface distance (ICPD). Age-stratified analysis, parameter correlation, and ROC curve evaluation were performed.

Compared with controls, the observation group showed significantly shallower anterior chambers (reduced ACD), narrower angles (decreased AOD/TIA), and posterior iris bowing (elevated IC) (all p < 0.05). These differences were more pronounced in elderly subgroups, with IC, ACD, and AOD750 demonstrating strong discriminative power in ROC analysis (AUC > 0.7). Correlation analysis revealed AOD500 was positively associated with ACD and TIA but negatively with IC and IT750, suggesting interconnected angle anatomy modulated by age.

Fellow eyes of unilateral NVG patients exhibit multiple abnormal anterior segment alterations despite being clinically unaffected, particularly in the elderly. UBM provides reliable quantitative indicators for early high-risk identification, with IC, ACD, and AOD750 serving as potential warning parameters, laying a theoretical foundation for risk screening models and preventive strategies.