Does glaucoma always affect both eyes?

Glaucoma often affects both eyes, but not always equally — one eye can be more advanced than the other, which is why both eyes are tested and monitored individually.

Is vision lost to glaucoma reversible?

Unfortunately, vision already lost to glaucoma is permanent. Treatment can slow or stop further damage, which is why early detection matters so much.

Can lifestyle changes help manage glaucoma?

Yes — regular exercise, a balanced diet rich in antioxidants, avoiding smoking, and protecting your eyes from injury all support overall eye health alongside your prescribed treatment.

Do glasses or contact lenses treat glaucoma?

No — glasses and contacts correct refractive errors like short-sightedness, but they don't treat or slow glaucoma. Glaucoma needs its own dedicated treatment.

Is glaucoma more common in men or women?

Some types are slightly more common in one sex, but overall risk depends far more on age, ethnicity and family history than on gender alone.

Glaucoma: What It Is, Symptoms, Causes, Types & Treatment

Quick Answer

Glaucoma is a group of eye conditions that damage the optic nerve, usually linked to raised eye pressure, and is a leading cause of irreversible blindness worldwide. Early stages are often symptom-free, which is why it's called the “silent thief of sight”— regular eye exams are the only reliable way to catch it before vision loss occurs. Treatment ranges from daily eye drops to laser and surgery, and can't reverse existing damage but can stop it progressing further.

What Is Glaucoma?

Glaucoma damages the optic nerve, the structure that carries visual information from your eye to your brain. It's most often caused by a build-up of fluid pressure inside the eye, though some people develop glaucoma with entirely normal pressure. Left untreated, it causes permanent peripheral vision loss that can progress to central vision loss and blindness.

Because early glaucoma rarely causes noticeable symptoms, many people don't realise they have it until significant damage has already occurred — which is exactly why comprehensive eye exams matter, even when your vision feels fine.

Symptoms of Glaucoma

Often no symptoms at all in the early stages
Subtle, then progressive loss of peripheral (side) vision
Halos around lights, particularly at night
Sudden severe eye pain, nausea or vomiting — a medical emergency

Causes & Risk Factors

The main driver is raised eye pressure from impaired fluid drainage, though genetics, injury and other health conditions all play a role. Key risk factors include:

Family history of glaucomaAge over 40, especially over 60African, Asian or Hispanic ethnicityPrevious eye injuryLong-term steroid useDiabetes, hypertension or migraineThin corneas

Types of Glaucoma

Glaucoma isn't one disease — primary open-angle glaucoma is the most common form, progressing slowly and silently. Angle-closure glaucoma can develop suddenly as a medical emergency. Other forms include normal-tension, secondary, congenital and exfoliative glaucoma, each with its own cause and risk profile.

For a detailed breakdown of each type, read our full guide: What Are the Different Types of Glaucoma?

Worried about your glaucoma risk?

A comprehensive eye exam, including pressure testing and optic nerve imaging, is the best way to catch glaucoma early.

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How Glaucoma Is Diagnosed

Glaucoma can't be detected by a simple vision check alone. A combination of tests builds a complete picture:

Tonometry

Measures the pressure inside the eye.

Visual Field Test

Checks for blind spots and peripheral vision loss.

OCT Scan

Detailed imaging of the optic nerve and retinal nerve fibres.

Gonioscopy

Examines the drainage angle to classify open vs angle-closure glaucoma.

Pachymetry

Measures corneal thickness, which affects how pressure readings are interpreted.

Treatment Options

There's no cure for glaucoma, but early and ongoing treatment can prevent or slow further vision loss. Most people start with daily eye drops, step up to laser treatment if needed, and only consider surgery when drops and laser can't control pressure adequately. Very few glaucoma patients ever need surgery.

If you'd like to understand the surgical options in more depth, read: Glaucoma Surgery Explained: Trabeculectomy, MIGS & Tube Shunts

Living with glaucoma is a lifelong process

Attending every follow-up, using medications exactly as prescribed, and reporting any vision changes promptly are the habits that protect your sight over the long term.

Conclusion

Glaucoma doesn't have to mean losing your sight — but it does require ongoing care. With regular eye exams from age 40 (earlier if you have risk factors), early diagnosis, and consistent treatment, most people retain good functional vision for life.

Frequently Asked Questions

Glaucoma can't always be prevented, but regular eye exams, a healthy lifestyle, and controlling risk factors like high blood pressure and diabetes can all help reduce your risk of vision loss.

Written by

Dr Mariana Sheales

Dr Mariana Sheales manages glaucoma at Clarity Eye Surgeons, from diagnosis and drops through to laser and surgical care, alongside cataract surgery and diabetic eye disease.

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