Ocular hypertension is when the pressure in your eyes, your intraocular pressure (IOP), is higher than normal. An IOP reading of 21 mmHg, millimeters of mercury, or higher generally signifies ocular hypertension.

Let’s take a quick look at the anatomy of the eye before we go further.
The space between the cornea, the clear front surface of the eye, and the lens inside the eye is filled with a clear fluid called the aqueous humor. This fluid provides nutrients to the anterior part of the eye and helps maintain the shape of the eye by keeping it pressurized.

The aqueous humor is produced 24/7 by a structure called the ciliary body, and it drains from the eye through a mesh-like tube called the trabecular meshwork. This structure is located in the angle formed where the cornea and iris meet.

IOP can become high if the ciliary body produces too much aqueous or if the aqueous drains too slowly through the trabecular meshwork. Some steroids and other medications can increase the risk of ocular hypertension. An injury to the eye or trauma to the eye can throw off the balance between aqueous production and drainage causing a build-up in pressure.

Your eye doctor may prescribe drops to help increase outflow drainage of aqueous or slow down the production of aqueous to treat ocular hypertension.

References
Heiting, G. (2018). Ocular hypertension: five causes of high eye pressure. All About Vision. Retrieved December 13, 2019, from http://allaboutvision.com/conditions/hypertension.htm
Berdhal, J. (2019). Glaucoma: symptoms, treatment and prevention. All About Vision. Retrieved December 13, 2019, from http://allaboutvision.com/conditions/glaucoma.htm