Overview
Glaucoma is a group of eye conditions in which the optic nerve, which connects the eye to the brain, is damaged. It is usually caused by increased pressure in the eye (intraocular pressure), though it can occur with normal pressure. It is the leading cause of irreversible blindness worldwide and typically has no symptoms until significant damage has occurred.
How common is it?
Glaucoma becomes more common with age. NHS England estimates that about 2 in 100 people aged 40 to 59 and 10 in 100 people over 75 in the UK are affected.
Causes and risk factors
Fluid produced inside the eye drains through a small channel. When drainage is impaired, pressure builds up and gradually damages the optic nerve fibres, starting from the peripheral visual field.
Common risk factors
- Age over 40
- Family history of glaucoma (first-degree relative)
- High intraocular pressure
- Black African or Caribbean ancestry (higher risk)
- Long-sightedness (angle closure) or short-sightedness (open angle)
- Prolonged use of steroid eye drops or medications
- Eye injury or previous eye inflammation
Symptoms
- Usually NO symptoms in the early stages
- Gradual loss of peripheral (side) vision, which may only be noticed late
- In acute angle-closure glaucoma: sudden severe eye pain, headache, blurred vision, halos around lights, nausea
When to see a doctor
Go to an emergency department immediately for sudden severe eye pain, a red eye with blurred vision, or suddenly seeing rainbow haloes around lights, especially with nausea or headache. Do not wait for every symptom or drive yourself. Have routine eye tests at least every 2 years, or as advised.
Diagnosis
Intraocular pressure measurement, visual field testing, and optic disc assessment (ophthalmoscopy or OCT scanning) diagnose glaucoma. Gonioscopy assesses the drainage angle.
Treatments
Eye drops to lower intraocular pressure
Prostaglandin analogues (latanoprost), beta-blockers (timolol), and other drops lower eye pressure. Use prescribed drops consistently. Treatment is usually long term, but an eye specialist may change drops or recommend laser or surgery. Do not stop drops yourself.
Laser treatment
Selective laser trabeculoplasty (SLT) improves drainage and can reduce or replace the need for eye drops in suitable patients.
Surgery (trabeculectomy or drainage implants)
Creates a new drainage channel for fluid when drops and laser fail to control pressure adequately.
Self-care and lifestyle
- Use eye drops exactly as prescribed, including on days when you feel well
- Attend all follow-up appointments as progression must be monitored
- Inform all your doctors and dentists that you have glaucoma
- Have routine eye tests at least every 2 years, or more often if your optometrist advises because of your risk. Follow the separate monitoring schedule set by your glaucoma specialist.
Prevention
Glaucoma cannot be fully prevented, but early detection through regular eye tests and consistent treatment preserve vision. Family members of people with glaucoma should have regular eye screening.
Sources for targeted updates
Updated: 24 October 2026. Targeted corrections to treatment, self-care, urgent-care guidance, frequency, key facts. This update covers the named sections; a full review of the remaining guide is pending.