Overview
Definition
A group of eye conditions that damage the optic nerve, often (but not always) associated with abnormally high intraocular pressure (IOP).
Epidemiology
A leading cause of irreversible blindness worldwide.
Etiology & Risk Factors
- Open-Angle (Most Common): Slow clogging of the trabecular meshwork, causing gradual IOP increase.
- Angle-Closure (Emergency): Sudden blockage of aqueous humor drainage by the iris, causing a rapid, dangerous spike in IOP.
Clinical Symptoms
- Primary Open-Angle Glaucoma (POAG): Asymptomatic until late stages; gradual loss of peripheral vision (tunnel vision)
- Acute Angle-Closure Glaucoma (AACG): Sudden onset severe eye pain, blurred vision, 'halos' around lights, intensely red eye, fixed mid-dilated pupil, nausea/vomiting
Clinical Approach
Diagnosis
- Tonometry: Measures IOP (Normal is 10-21 mmHg)
- Fundoscopy: Optic disc cupping (increased cup-to-disc ratio)
- Visual Field Testing: Confirms peripheral vision loss
- Gonioscopy: Evaluates the iridocorneal angle (open vs closed)
Management
- Open-Angle: Prostaglandin analogs (Latanoprost - increases outflow), Beta-blockers (Timolol - decreases production)
- Acute Angle-Closure: EMERGENT treatment. IV Acetazolamide, topical Pilocarpine (constricts pupil to pull iris away from the angle), topical beta-blockers. Definitive treatment is Laser Peripheral Iridotomy.
Complications
- Irreversible, permanent blindness (starting with peripheral vision, progressing to central)