Variety of factors. Person who has immediate relative with glaucoma (parents or siblings), with large cupped optic nerves and high eye pressures (above 21), with history of blunt eye trauma would i think be at most risk for glaucoma.
Very high pressure. The highest risk is if your eye pressure was extremely high, for example iop 60 (most population is 10-21). This type of pressure, if an acute rise, is often symptomatic with red eye, pain, decreased vision.