Glaucoma is the name given to a group of diseases which cause progressive gradual degeneration of the optic nerve and eventually blindness.  Glaucoma is caused by a number of factors which can include high internal pressure of the eye, poor blood flow to the eye, over 35 years of age, and genetic factors.  Glaucoma affects the peripheral vision, and often goes unnoticed by the patient.  Very rarely, glaucoma can affect people very suddenly making them feel sick and causing pain to the eyes – in these cases immediate urgent assessment is advised.  If left untreated, vision loss cannot be restored only halted.  As there are usually no early warning signs, regular eye exams are crucial especially for over 35 year olds and people with a family history of glaucoma.