Ocular hypertension
Ocular hypertension | |
---|---|
Specialty | Ophthalmology |
Ocular hypertension is the presence of elevated fluid pressure inside the eye (intraocular pressure), usually with no optic nerve damage or visual field loss.[1][2]
For most individuals, the normal range of intraocular pressure is between 10 mmHg and 21 mmHg.[3][4] Elevated intraocular pressure is an important risk factor for glaucoma. One study found that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma.[5] 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.
Pathophysiology
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.[6]
Diagnosis
The condition is diagnosed using ocular tonometry and glaucoma evaluation. Increased IOP without glaucomatous changes (in optic disc or visual field) is considered as ocular hypertension.[6]
Treatment
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 regarding the use of marijuana as a treatment for glaucoma.[7]
Research
The LiGHT trial compared the effectiveness of eye drops and selective laser trabeculoplasty for ocular hypertension and open angle glaucoma. Both treatments contributed to a similar quality of life but most people undergoing laser treatment were able to stop using eye drops. Laser trabeculoplasty was also shown to be more cost-effective.[8]
References
- ^ "Ocular Hypertension, Glaucoma & Eye Drops" (PDF). American Academy of Ophthalmology. June 2002. Archived from the original (PDF) on 25 November 2005.
- ^ "Ocular Hypertension". American Optometric Association.
- ^ "Tonometry". webMD.
- ^ "Glaucoma Overview". eMedicine. Archived from the original on 2008-07-04. Retrieved 2005-12-28.
- ^ Kass MA, Heuer DK, Higginbotham EJ, Johnson CA, Keltner JL, Miller JP, et al. (June 2002). "The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma". Archives of Ophthalmology. 120 (6): 701–713. doi:10.1001/archopht.120.6.701. PMID 12049574.
- ^ a b Salmon, John F. (2020). "Glaucoma". Kanski's clinical ophthalmology : a systematic approach (9th ed.). Edinburgh: Elsevier. ISBN 978-0-7020-7713-5. OCLC 1131846767.
- ^ Jampel H (February 2010). "American glaucoma society position statement: marijuana and the treatment of glaucoma". Journal of Glaucoma. 19 (2): 75–76. doi:10.1097/ijg.0b013e3181d12e39. PMID 20160576.
- ^ Gazzard G, Konstantakopoulou E, Garway-Heath D, Garg A, Vickerstaff V, Hunter R, et al. (April 2019). "Selective laser trabeculoplasty versus eye drops for first-line treatment of ocular hypertension and glaucoma (LiGHT): a multicentre randomised controlled trial". Lancet. 393 (10180): 1505–1516. doi:10.1016/S0140-6736(18)32213-X. PMC 6495367. PMID 30862377.; Lay summary in: "A laser eye procedure can be effective and safe if used early as treatment for glaucoma". NIHR Evidence. National Institute for Health and Care Research. 4 June 2019. doi:10.3310/signal-000774.
Plain English summary