Glaucoma is a group of eye diseases which result in damage to the optic nerve and vision loss . Open-angle gl auc oma develops slowly over time and there is no pain. Side vision may begin to decrease followed by central vision resulting in blindness if not treated. Glaucoma Risk factors for glaucoma include : increased pressure in the eye , a family history of the condition migraines , high blood pressure , and obesity . . National Eye Institute . Retrieved 29 March 2016 .