|Classification and external resources|
For most individuals, the normal range of introcular pressure is between 10 mmHg and 21 mmHg. Elevated intraocular pressure is an important risk factor for glaucoma. The Ocular Hypertension Treatment Study, a large, multicentered, randomized clinical trial, determined that topical ocular hypotensive medication delays or prevents the onset of Primary Open-Angle Glaucoma. Accordingly, most individuals with consistently elevated intraocular pressures of greater than 21mmHg, particularly if they have other risk factors, are treated in an effort to prevent vision loss from glaucoma.
The pressure within the eye is maintained by the balance between the fluid that enters the eye through the ciliary body and the fluid that exits the eye through the trabecular meshwork.
Ocular hypertension is treated with either medications or laser. Medications that lower intraocular pressure work by decreasing aqueous humor production and/or increasing aqueous humor outflow. Laser trabeculoplasty works by increasing outflow. The cannabinoids found in cannabis sativa and indica (marijuana) have been shown to reduce intraocular pressure, by up to 50% for approximately four to five hours. But due to the duration of effect, significant side-effect profile, and lack of research proving efficacy, the American Glaucoma Society issued a position statement in 2009 against the use of marijuana as a treatment for glaucoma. 
- American Academy of Ophthalmology[dead link]
- American Optometric Association - Ocular Hypertension
- webMD - Tonometry
- eMedicine - Glaucoma Overview
- Kass, M.A. (2002). "The Ocular Hypertension Treatment Study.". Arch Ophthalmol 120 (6): 701–713.
- Jampel, H (2010). "American Glaucoma Society Position Statement: Marijuana and the treatment of glaucoma". J Glaucoma 19 (2): 75.