The most common type of glaucoma affects people who are in their middle age or the elderly lot. Due to hereditary tendency, relatives of people with this form of glaucoma are at a higher risk of developing this disease. Dr Chuah Kay-Leong states that people who are short-sighted are also at risk.

This kind of glaucoma is not noticed for several years because it progresses slowly. It also until the end stage does not affect the straight-ahead vision and reading vision. People with this kind of glaucoma also experience a slow loss of night vision and side vision.

Glaucoma eye drops does well for this kind of glaucoma but surgery is also needed in some cases. An additional drainage channel for the eye fluid to relieve the eye pressure is provided by the surgery.

This is the commonest type of glaucoma among the Chinese.

Dr Chuah said, "It affects the middle age and elderly, especially women. There is a sudden severe increase of pressure in the eye, resulting in permanent blindness if the eye pressure is not brought down promptly."