Sex differences in canine anterior chamber dimensions: Potential implications for primary angle-closure glaucoma.

Abstract

OBJECTIVES: This study aimed to explore anatomical differences in the aqueous humor (AH) outflow pathway between male and female dogs using ultrasound biomicroscopy (UBM). ANIMALS STUDIED: Clinical data were collected from 30 eyes of 30 dogs (15 males: 10 right eyes, 5 left eyes; and 15 females: 7 right eyes, 8 left eyes) treated at the Veterinary Medical Teaching Hospital of Chungbuk National University, South Korea, between August 2018 and February 2024. PROCEDURE: The study conducted an in-depth UBM examination, specifically observing peripheral anterior chamber depth (ACD), geometric iridocorneal angle (ICA), and angle-opening distance (AOD) alongside measurements of ciliary cleft width (CCW), length (CCL), and area (CCA), and assessed the longitudinal fibers of ciliary muscle thickness (Lf-CMT) and the longitudinal and radial fibers of ciliary muscle thickness (LRf-CMT) for sex-based differences. RESULTS: The study identified a significant sex difference in peripheral ACD, with females displaying shallower depths compared to males, potentially clarifying the higher incidence of glaucoma in female dogs. No significant sex differences were found in ICA, AOD, CC parameters, or ciliary muscle parameters measurements. CONCLUSION: This research uncovered that peripheral ACD is significantly shallower in females than in males, potentially indicating a risk factor that could contribute to the development of primary angle-closure glaucoma.