Primary Open-Angle Glaucoma

Definition

Primary open-angle glaucoma (POAG) is a chronic, progressive optic neuropathy characterized by an open anterior chamber angle, elevated or normal intraocular pressure, and progressive visual field loss.

Epidemiology

• Most common form of glaucoma worldwide
• Prevalence increases with age, especially after 40 years
• Higher prevalence in African, Hispanic, and Asian populations
• Often asymptomatic until advanced stages
• Estimated to affect over 60 million people globally

Etiology

• Multifactorial: genetic predisposition, impaired aqueous humor outflow
• Risk factors: elevated intraocular pressure, family history, age, myopia, systemic hypertension, diabetes
• Optic nerve susceptibility varies among individuals
• Environmental factors may contribute to disease progression

Pathophysiology

• Progressive loss of retinal ganglion cells and optic nerve fibers
• Elevated IOP causes mechanical stress and ischemia at the optic nerve head
• Open angle impedes aqueous outflow at the trabecular meshwork, leading to gradual IOP elevation
• Chronic damage results in characteristic optic disc cupping and visual field loss
• Vascular dysregulation and oxidative stress contribute to neurodegeneration
• Disease progresses slowly and may be unnoticed until significant visual impairment occurs