Lots of causes. There many causes for this common condition, that may lead to glaucoma. That is why it is a good to see a professional to get your eye pressure checked. Some of the risks for this are: near sightedness, family history, age over 40, history of diabetes, use of steroid medication, history of eye trauma or surgery, anything going on the eye that restricts flow of the eye fluids, and afroamericans.
Yes. Ocular hypertension usually refers to borderline glaucoma, or high pressure that hasn't caused detectable damage to the optic nerve yet and thus are suspects. A sustained rise that's too high for the nerve can lead to damage over time. There is primary and many secondary causes for glaucoma.
Genetics or injury. Dr fein has the comprehensive answer above. African americans have a high incidence of severe vision loss from open angle glaucoma and native alaskan eskimos and Asian patients have a higher incidence of blinding angle closure glaucoma than other populations. Because open angle glaucoma typically has no symptoms everyone should have an eye pressure chk by 30yrs.