TELL glaucoma patients that they have green eyes and they would protest. That's because glaucoma is known as qing guang yen in Mandarin, which literally translates to "green light eye," says consultant ophthalmologist Dr Chuah Kay-Leong.

The Chinese term for glaucoma is a misnomer and confusing. When Dr Chuah mentions the word for glaucoma in Chinese to his patients, they always brush it off. One patient says: "No, I don't see any green light in my eye."

Then, Dr Chuah, a specialist in cornea, external eye diseases, cataract and refractive surgery, has to explain what glaucoma means. He has not the faintest idea how the Chinese term for glaucoma came about.

Glaucoma is a disease in which the optic nerve is damaged, leading to progressive vision loss. It is often associated with increased pressure (intraocular pressure) of the fluid in the eye. Some people develop glaucoma as a result of raised eye pressure. But those with normal eye pressure can also end up with it because of a weak optic nerve.