Glaucoma

What it is

Glaucoma damages the optic nerve that carries vision to the brain. It is a leading cause of irreversible blindness worldwide. Eye pressure is a major risk factor, but some people develop glaucoma with normal pressure (normal-tension glaucoma).

Open-angle versus angle-closure

Primary open-angle glaucoma is slow, painless and chronic — drainage channels clog gradually. Angle-closure glaucoma happens when the iris blocks drainage suddenly or intermittently, causing a rapid pressure rise. Acute angle-closure is an emergency with severe pain, headache, nausea, halos and blurred vision.

Risk factors and screening

Higher risk with age over 40, family history, African-Caribbean or Hispanic heritage for open-angle types, East Asian heritage for angle closure, diabetes, short-sightedness, long-term steroid use and previous eye injury. Adults should have regular eye tests including pressure, optic nerve examination and visual field testing when indicated.

Diagnosis

Tests include eye pressure (tonometry), optic nerve assessment (with OCT imaging in many clinics), visual field tests and gonioscopy to examine the drainage angle. One high pressure reading does not always mean glaucoma — repeated measures and nerve appearance matter.

Treatment pathway

Treatment lowers pressure to slow further damage — it cannot reverse existing loss.

• Daily pressure-lowering drops — see the using glaucoma drops guide for technique
• Laser trabeculoplasty (SLT) to improve drainage in open-angle disease
• Laser iridotomy for angle-closure risk
• Surgery (trabeculectomy, MIGS devices) when drops and laser are insufficient

Living with glaucoma

Lifelong monitoring is needed even when pressure is controlled. Report side effects from drops — alternatives exist. Tell all doctors you use glaucoma medicines before surgery. Driving rules depend on visual field results in your country.