Glaucoma

Glaucoma is a group of eye diseases that damage the optic nerve — the nerve carrying signals from the eye to the brain. It is usually (but not always) caused by raised pressure inside the eye. Glaucoma is painless in its commonest form and silently steals peripheral (side) vision first. Vision lost to glaucoma cannot be recovered — which is why early detection matters.

Main types

• Open-angle glaucoma — commonest; slow, painless loss of side vision.
• Angle-closure glaucoma — can be gradual or sudden; sudden type is an emergency.
• Normal-tension glaucoma — nerve damage even at normal pressure.
• Congenital glaucoma — in infants and young children; treatable if caught early.
• Secondary glaucoma — after eye injury, long-term steroid use, advanced diabetes, or certain other eye diseases.

Red flags — urgent acute angle-closure

• Sudden severe eye pain.
• Headache with nausea or vomiting.
• Blurred vision with coloured rings (halos) around lights.
• A red eye with a fixed, mid-dilated pupil.
• Dial 112 or get to an eye emergency immediately — permanent vision loss can occur within hours.

Who should be screened

• Anyone over 40 — periodic eye check.
• Family history of glaucoma.
• Diabetes.
• People on long-term steroid drops, inhalers or tablets.
• Previous eye injury.
• High myopia (short-sightedness).

Tests

Measurement of eye pressure (tonometry), examination of the optic nerve, a visual field test, and sometimes OCT (optical scan of the nerve). These are routine at any eye hospital.

Treatment — lifelong

• Eye drops to lower pressure — the main treatment. Most people need them for life.
• Laser treatment for certain types.
• Surgery (trabeculectomy or valve implants) when drops aren't enough.
• Do not stop drops because you feel nothing and see normally — glaucoma is silent until late.

India context

Glaucoma causes a large share of permanent blindness in India — much of it preventable with early diagnosis. Most people first learn they have glaucoma during a routine eye check for spectacles. One eye check-up every 2 years after 40 is the single most effective screening step.