Editing Glaucoma (section)

=== Ocular hypertension ===
[[Ocular hypertension]] (increased pressure within the eye) is an important risk factor for glaucoma, but only about 10-70% of people - depending on ethnic group - with primary open-angle glaucoma actually have elevated ocular pressure.<ref name="pmid26886116">{{cite journal| author=Kim KE, Park KH| title=Update on the Prevalence, Etiology, Diagnosis, and Monitoring of Normal-Tension Glaucoma. | journal=Asia Pac J Ophthalmol (Phila) | year= 2016 | volume= 5 | issue= 1 | pages= 23–31 | pmid=26886116 | doi=10.1097/APO.0000000000000177 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26886116  }}, (review) (open access).</ref> Ocular hypertension&mdash;an intraocular pressure above the traditional threshold of {{cvt|21|mmHg|hPa}} or even above {{cvt|24|mmHg|hPa}}&mdash;is not necessarily a pathological condition, but it increases the risk of developing glaucoma. 

A study with 1636 persons aged 40-80 who had an intraocular pressure above 24{{nbsp}}mmHg in at least one eye, but no indications of eye damages, showed that after five years, 9.5% of the untreated participants and 4.4% of the treated participants had developed glaucomatous symptoms, meaning that only about one in 10 untreated people with elevated intraocular pressure will develop glaucomatous symptoms over that period of time.<ref name="pmid29501371" /> Given these results, the clinical decision to treat everyone with elevated intraocular pressure with glaucoma therapy as a preventative measure is a matter of debate.<ref name="pmid29501371" /> As of 2018, most ophthalmologists favored treatment of those with additional risk factors.<ref name="pmid29501371">{{cite journal| author=Gordon MO, Kass MA| title=What We Have Learned From the Ocular Hypertension Treatment Study. | journal=Am J Ophthalmol | year= 2018 | volume= 189 | issue=  | pages= xxiv-xxvii | pmid=29501371 | doi=10.1016/j.ajo.2018.02.016 | pmc=5915899 }} </ref>

For eye pressures, a value of {{cvt|21|mmHg|hPa|disp=flip}} above [[atmospheric pressure]] {{cvt|760|mmHg|hPa|disp=flip}} is often used, with higher pressures leading to a greater risk.<ref name="Man2015" /><ref>{{cite book |url=https://books.google.com/books?id=vbWWuX1dgjYC&pg=PA180 |title=Glaucoma |vauthors=Rhee DJ |date=2012 |publisher=Wolters Kluwer Health/Lippincott Williams & Wilkins |isbn=978-1-60913-337-5 |edition=2nd |location=Philadelphia |page=180 |oclc=744299538}}</ref> However, some may have high eye pressure for years and never develop damage.<ref name="Man2015" /> Conversely, optic nerve damage may occur with normal pressure, known as normal-tension glaucoma.<ref>{{cite journal |vauthors=Mi XS, Yuan TF, So KF |date=16 September 2014 |title=The current research status of normal tension glaucoma |journal=Clinical Interventions in Aging |volume=9 |pages=1563–1571 |doi=10.2147/CIA.S67263 |pmc=4172068 |pmid=25258525 |doi-access=free}}</ref> In case of above-normal intraocular pressure, the mechanism of open-angle glaucoma is believed to be the impeded exit of aqueous humor through the trabecular meshwork, while in closed-angle glaucoma, the [[iris (anatomy)|iris]] blocks the trabecular meshwork.<ref name="Man2015" /> Diagnosis is achieved by performing an [[eye examination]].<ref name="NIH2016Fact" /> Often, the optic nerve shows an abnormal amount of [[optic cup (anatomical)|cupping]].<ref name="Man2015" />