Not everyone with low eye pressure or high eye pressure develops glaucoma. Even individuals with normal eye pressure can develop glaucoma, according to the National Eye Institute. The possibility that people have glaucoma depends on the level of eye pressure they can tolerate without damaging the optic nerve.
Glaucoma is an eye disease that damages a person's optic nerve, which results in the loss of vision, as defined by the National Eye Institute. Normally, a clear fluid in the anterior chamber of the eye flows in and out continuously through what is known as the open angle. In the most common type of glaucoma, open-angle glaucoma, the fluid flows slowly. This builds up eye pressure to a high level that eventually damages the optic nerve.
Another form of glaucoma develops in people with normal eye pressure and is called low-tension or normal-tension glaucoma, as explained by the National Eye Institute. Further lowering eye pressure through eye drops or pills may or may not delay the progression of the disease.
Two other forms of glaucoma are described by the National Eye Institute. In angle-closure glaucoma, the open angle is blocked and the fluid does not drain, which leads to sudden high pressure. Emergency treatment is necessary in this case to avoid blindness. Glaucoma can also appear in babies at birth as congenital glaucoma.