Drugs, alcohol, smoking and certain medications can contribute to macular degeneration. Glaucoma Glaucoma is an eye condition in which the optic nerve is damaged by raised pressure within the eye. Intra-ocular pressure is not directly related to blood pressure. If the fluid cannot escape because the channels become narrowed or blocked, then intra-ocular pressure rises. This increased pressure damages the optic nerve that sends visual information to the brain.
Damage progresses very slowly and destroys vision gradually, starting with the side vision.
One eye covers for the other, and the person remains unaware of any problem until a majority of nerve fibres has been destroyed and a large part of vision has been destroyed. If treatment is delayed, these defects can become permanent and severely affect vision. People with glaucoma may not know they have it. The pressure in the eye usually rises slowly so that the symptoms may not be noticed. There is no pain and the eyesight will seem to be unchanged.