Dr Alastair Lockwood, ophthalmologist and eye health specialist at Feel Good Contacts, said: “Glaucoma is one of the most common causes of irreversible blindness.
“It is where the optic nerve (the electrical cable that carries information from your eye to your brain) degenerates more quickly than it should, usually because the pressure within the eye is too high.
“There are different reasons why the eye pressure can increase, indeed we do need eye pressure otherwise our eyes would collapse like a balloon with no air in.
“There is therefore a continuous circulation of fluid inside the eye, and pressure rise is usually gradual and caused by increased resistance of drainage of fluid from the eye into the bloodstream.
“More rarely, the eye pressure can rise because the lens inside the eye runs out of space (the lens is one of the few things that continues growing throughout our life like our hair and nails).
“If this happens then the pressure rise can be very abrupt, high and painful – acute angle closure glaucoma.”
READ MORE: High blood pressure: The best fruit that can lower your BP that’s not a banana