Glaucoma is a progressive eye disease in which elevated pressure within the eye damages the optic nerve. This can lead to serious vision loss of not detected and treated early. The optic nerve is the nerve that takes all of the information the eye sees and transmits that information to the brain. The elevated pressure is due to either an increase in the production, or a decrease in the drainage, of fluid normally produced inside your eye. Glaucoma is one of the leading causes of blindness in Canada.