Although the normal pressure lies between 10-21 mmHg, even if your pressure is more than 21 mmHg you may not have glaucoma. A person is diagnosed to have glaucoma only if the optic nerve is damaged. In addition if your cornea is thicker, then the eye pressure may be over-estimated by the measuring instrument. If you have increased eye pressure but no damage to the optic nerve, you do not have glaucoma but you are at an increased risk for developing it, and should discuss management with your ophthalmologist.
This condition is known as ocular hypertension (see Ocular hypertension and Intraocular pressure).
