Primary Angle-Closure Glaucoma

Definition

Primary angle-closure glaucoma (PACG) is a type of glaucoma characterized by sudden or chronic closure of the anterior chamber angle, leading to increased intraocular pressure (IOP) and optic nerve damage.

Epidemiology

• More common in East Asian populations than in Caucasians
• Typically affects individuals over 40 years of age
• Females are at higher risk due to shallower anterior chambers
• Accounts for approximately 50% of glaucoma-related blindness worldwide
• Often unilateral initially but can affect both eyes over time

Etiology

• Anatomical predisposition: shallow anterior chamber, narrow angle, thick lens
• Hyperopia (farsightedness) increases risk
• Age-related lens thickening
• Family history of angle-closure glaucoma
• Triggers: pupillary dilation (dim light, medications), emotional stress, certain drugs (anticholinergics, sympathomimetics)

Pathophysiology

• Anterior chamber angle closure impedes aqueous humor drainage through trabecular meshwork
• Sudden angle closure causes acute rise in IOP
• Optic nerve head damage occurs due to elevated IOP and ischemia
• Peripheral anterior synechiae (PAS) may develop in chronic cases
• Acute episodes lead to corneal edema, anterior chamber inflammation, and visual symptoms
• Chronic closure causes progressive optic neuropathy and visual field loss