Glaucoma is a common eye condition where the optic nerve, which connects the eye to the brain, becomes damaged. It's usually caused by fluid building up in the front part of the eye, which increases pressure inside the eye. Glaucoma can lead to loss of vision if it's not diagnosed and treated early. It can affect people of all ages, but is most common in adults in their 70s and 80s.
It causes optic nerve damage due to changes in the pressure in the eye and can lead to loss of peripheral (side) vision which means that people with this condition may not see things or people that are approaching from the side.
People who are developing glaucoma are often unaware that there is anything wrong but it can be detected by special tests at the opticians.