Glaucoma

Partial or complete blindness caused by increased pressure in the eye and changes in the blood flow in the optic nerve that can damage cells in the retina called retinal ganglion cells.  Central vision is then lost.  Symptoms include apparent halos around light, headaches, nausea, blurred or reduced vision, or eye pain.  Treatment to decrease pressure inside the eye by medication, laser, or conventional surgery often halts the progress of the condition, but vision that has already been lost cannot be recovered.