Glaucoma is the collective term used to describe damage to the optic nerve (optic neuropathy). Glaucoma affects two in 100 people over the age of 40 and one in 20 people aged over 80.

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What is glaucoma?

Glaucoma describes damage to the optic nerve. When sight loss occurs from Glaucoma it often begins by affecting peripheral vision.

Glaucoma is usually caused by a build-up of fluid at the front of the eye that’s blocked or not draining properly. As a result, pressure (known as intra ocular pressure) builds in the eye, damaging the optic nerve. Damage can also be caused if the optic nerve has a weak structure. 

There are several types of glaucoma, including chronic open-angle, primary angle closure, secondary glaucoma and congenital glaucoma. Chronic open-angle glaucoma is the most common type and there’s often no detectable change in your vision until significant damage has occurred. That’s one reason why having regular eye tests is so important in order to catch glaucoma early. You are entitled to a free eye test if you are over 40 and if you have a family history of Glaucoma.


Sight loss from glaucoma usually begins with your peripheral vision, often in the vision closest to the sides of your nose (mid-periphery) first. It can also affect your ability to see detail (acuity) and, if the condition progresses, it can affect the entire visual field. 


Glaucoma can be treated with drops and/or surgery.

Practical implications

If you have glaucoma, you may have difficulty with:

  • Navigating safely at dusk, night-time or on very dull winter days
  • Seeing outdoors in very bright sunlight
  • Sudden changes in lighting, for example when moving from indoors to outdoors, and it may take some time for your vision to adapt
  • Being dazzled by bright reflections on wet roads or reflective buildings
  • Moving around outside and avoiding street obstacles and hazards
  • Locating kerbs, steps and using stairs (if you have lower peripheral vision loss)

If your central vision and ability to see detail are also affected, you might have difficulty with:

  • Distinguishing colours
  • Pouring a drink
  • Selecting the right item from similar ones (different tins of fruit for example) when shopping
  • Food preparation, for example chopping vegetables safely
A picture of a man using a magnifying glass to read a bottle

Find strategies that work for you 

Our series of helpful hints and tips will help you maintain your independence while learning new skills and strategies.

Find out more about symptoms, diagnosis and treatment on the NHS website

Glaucoma UK also has some useful information.