Purpose: To present evidence-based concepts that will explain mechanisms of angle-closure glaucoma.
Design: Review of published evidence and personal perspective.
Methods: Literature review and clinical research using imaging devices.
Results: When the pupil dilates, the iris typically decreases its volume by losing extracellular fluid. Eyes with angle-closure lose less iris volume with pupil dilation, contributing to obstruction of the trabecular meshwork. Expansion of choroidal volume is a dynamic phenomenon and is a major risk factor in angle-closure. The mechanism of malignant glaucoma seems likely to result from poor conductivity of fluid through the vitreous, and past suggestions that it results from "misdirected" aqueous are not consistent with physiological principles.
Conclusions: Angle-closure and angle-closure glaucoma result from disturbed physiological mechanisms more than from simple anatomic measures, and future predictive testing can exploit knowledge of these factors.