View source for Glaucoma

{{Short description|Group of eye diseases related to high pressure in the eye}}
{{cs1 config|name-list-style=vanc}}
{{Use dmy dates|date=January 2018}}
{{Use American English|date=December 2017}}
{{Infobox medical condition (new)
| name            = Glaucoma
| image           = Acute angle closure glaucoma.JPG
| caption         = Acute angle closure glaucoma of a person's right eye (shown at left). Note the mid-sized [[pupil (eye)|pupil]], which is non-[[pupillary light reflex|reactive to light]], and redness of the [[sclera|white part of the eye]].
| field           = [[Ophthalmology]], [[optometry]]
| symptoms        = {{hlist|[[Vision loss]]|eye pain|mid-dilated pupil|redness of the eye|[[nausea]]}}<ref name=NIH2016Fact/><ref name=Man2015/>
| complications   = 
| onset           = Gradual, or sudden<ref name=Man2015/>
| duration        = 
| causes          = 
| risks           = Increased [[intraocular pressure|pressure in the eye]], family history, [[high blood pressure]]<ref name=NIH2016Fact/>
| diagnosis       = Dilated [[eye examination]]<ref name=NIH2016Fact/>
| differential    = [[Uveitis]], trauma, [[keratitis]], [[conjunctivitis]]<ref>{{cite book| vauthors = Ferri FF |title=Ferri's differential diagnosis : a practical guide to the differential diagnosis of symptoms, signs, and clinical disorders|date=2010|publisher=Elsevier/Mosby|location=Philadelphia, PA|isbn=978-0-323-07699-9|page=Chapter G|edition=2nd}}</ref>
| prevention      = 
| treatment       = Medication, [[Laser medicine|laser]], surgery<ref name=NIH2016Fact/>
| medication      = 
| prognosis       = 
| frequency       = 6–67 million<ref name=Man2015/><ref name=GBD2015Pre>{{cite journal | title = Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015 | journal = Lancet | volume = 388 | issue = 10053 | pages = 1545–1602 | date = October 2016 | pmid = 27733282 | pmc = 5055577 | doi = 10.1016/S0140-6736(16)31678-6 | last1 = Vos | first1 = Theo | last2 = Allen | first2 = Christine | last3 = Arora | first3 = Megha | last4 = Barber | first4 = Ryan M. | last5 = Bhutta | first5 = Zulfiqar A. | last6 = Brown | first6 = Alexandria | last7 = Carter | first7 = Austin | last8 = Casey | first8 = Daniel C. | last9 = Charlson | first9 = Fiona J. | last10 = Chen | first10 = Alan Z. | last11 = Coggeshall | first11 = Megan | last12 = Cornaby | first12 = Leslie | last13 = Dandona | first13 = Lalit | last14 = Dicker | first14 = Daniel J. | last15 = Dilegge | first15 = Tina | last16 = Erskine | first16 = Holly E. | last17 = Ferrari | first17 = Alize J. | last18 = Fitzmaurice | first18 = Christina | last19 = Fleming | first19 = Tom | last20 = Forouzanfar | first20 = Mohammad H. | last21 = Fullman | first21 = Nancy | last22 = Gething | first22 = Peter W. | last23 = Goldberg | first23 = Ellen M. | last24 = Graetz | first24 = Nicholas | last25 = Haagsma | first25 = Juanita A. | last26 = Hay | first26 = Simon I. | last27 = Johnson | first27 = Catherine O. | last28 = Kassebaum | first28 = Nicholas J. | last29 = Kawashima | first29 = Toana | last30 = Kemmer | first30 = Laura | display-authors = 3 }}</ref>
| deaths          = 
}}

<!-- Definition and symptoms -->
'''Glaucoma''' is a group of eye diseases that can lead to damage of the [[optic nerve]]. The optic nerve transmits visual information from the eye to the brain. Glaucoma may cause [[vision loss]] if left untreated. It has been called the "silent thief of sight" because the loss of vision usually occurs slowly over a long period of time.<ref>{{cite press release |title=Glaucoma: The 'silent thief' begins to tell its secrets |date=21 January 2014 |publisher=National Eye Institute |url=https://nei.nih.gov/news/pressreleases/012114 |url-status=live |archive-url=https://web.archive.org/web/20150723082005/https://nei.nih.gov/news/pressreleases/012114 |archive-date=23 July 2015}}</ref> A major risk factor for glaucoma is increased pressure within the eye, known as [[Intraocular pressure|intraocular pressure (IOP)]].<ref name="NIH2016Fact">{{cite web|title=Facts About Glaucoma|url=https://nei.nih.gov/health/glaucoma/glaucoma_facts |website=National Eye Institute|access-date=29 March 2016|url-status=live|archive-date=28 March 2016 |archive-url=https://web.archive.org/web/20160328122443/https://nei.nih.gov/health/glaucoma/glaucoma_facts}}</ref> It is associated with old age, a family history of glaucoma, and certain medical conditions or the use of some medications.<ref name=":1">{{Cite web |title=Glaucoma: The 'silent thief' begins to tell its secrets {{!}} National Eye Institute |url=https://www.nei.nih.gov/about/news-and-events/news/glaucoma-silent-thief-begins-tell-its-secrets |access-date=2023-09-11 |website=www.nei.nih.gov |language=en}}</ref><!-- Cause and mechanism --> The word ''glaucoma'' comes from the [[Ancient Greek]] word {{lang|grc|γλαυκός}} ({{transliteration|grc|glaukós}}), meaning 'gleaming, blue-green, gray'.

Of the different types of glaucoma, the most common are called '''open-angle glaucoma''' and '''closed-angle glaucoma'''.<ref>{{Cite web |title=Glaucoma: MedlinePlus Medical Encyclopedia |url=https://medlineplus.gov/ency/article/001620.htm |access-date=2023-09-11 |website=medlineplus.gov |language=en}}</ref> Inside the eye, a liquid called [[Aqueous humour|aqueous humor]] helps to maintain shape and provides nutrients. The aqueous humor normally drains through the [[trabecular meshwork]]. In open-angle glaucoma, the draining is impeded, causing the liquid to accumulate and pressure inside the eye to increase. This elevated pressure can damage the optic nerve. In closed-angle glaucoma, the drainage of the eye becomes suddenly blocked, leading to a rapid increase in intraocular pressure. This may lead to [[Eye strain|intense eye pain]], [[blurred vision]], and [[nausea]]. Closed-angle glaucoma is an emergency requiring immediate attention.<ref name="NIH2016Fact" /><!-- Prevention and treatment -->

If treated early, slowing or stopping the progression of glaucoma is possible. Regular eye examinations, especially if the person is over 40 or has a family history of glaucoma, are essential for early detection.<ref>{{Cite web |title=Glaucoma - Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/glaucoma/symptoms-causes/syc-20372839 |access-date=2023-09-11 |website=Mayo Clinic |language=en}}</ref> Treatment typically includes prescription of eye drops, [[Glaucoma medication|medication]], [[Laser coagulation|laser treatment]] or [[Glaucoma surgery|surgery.]]<ref name="NIH2016Fact" /><ref name="Vass2007">{{cite journal | vauthors = Vass C, Hirn C, Sycha T, Findl O, Bauer P, Schmetterer L | title = Medical interventions for primary open angle glaucoma and ocular hypertension | journal = The Cochrane Database of Systematic Reviews | issue = 4 | pages = CD003167 | date = October 2007 | volume = 2007 | pmid = 17943780 | pmc = 6768994 | doi = 10.1002/14651858.CD003167.pub3 }}</ref> The goal of these treatments is to decrease eye pressure.<ref name="Man2015">{{cite journal |vauthors=Mantravadi AV, Vadhar N |date=September 2015 |title=Glaucoma |journal=Primary Care |volume=42 |issue=3 |pages=437–449 |doi=10.1016/j.pop.2015.05.008 |pmid=26319348}}</ref>

<!-- Epidemiology, history, society -->
Glaucoma is a leading cause of blindness in [[African Americans]], [[Hispanic and Latino Americans|Hispanic Americans]],<ref name="Ou">{{cite web | vauthors = Ou Y |title=Glaucoma in the African American and Hispanic Communities |url=https://www.brightfocus.org/glaucoma/article/glaucoma-african-american-and-hispanic-communities |website=Bright Focus Foundation |access-date= 26 June 2022}}</ref><ref name="AAO 2010">{{Cite web |date=2010-06-01 |title=Glaucoma in the African-American and Latino Communities: Studies Release More Data |url=https://www.aao.org/eyenet/article/glaucoma-in-african-american-latino-communities-st |access-date=2023-09-11 |website=American Academy of Ophthalmology |language=en}}</ref> and Asians.<ref>{{Cite journal |last1=Belamkar |first1=Aditya |last2=Harris |first2=Alon |last3=Oddone |first3=Francesco |last4=Verticchio Vercellin |first4=Alice |last5=Fabczak-Kubicka |first5=Anna |last6=Siesky |first6=Brent |date=2022-04-28 |title=Asian Race and Primary Open-Angle Glaucoma: Where Do We Stand? |journal=Journal of Clinical Medicine |volume=11 |issue=9 |pages=2486 |doi=10.3390/jcm11092486 |issn=2077-0383 |pmc=9099679 |pmid=35566612 |doi-access=free }}</ref> It occurs more commonly among older people,<ref name=NIH2016Fact/> and closed-angle glaucoma is more common in women.<ref name=Man2015/>
{{TOC limit}}

==Epidemiology==
[[File:Glaucoma world map - DALY - WHO2004.svg|thumb|upright=1.3|[[Disability-adjusted life year]] for glaucoma per 100,000&nbsp;inhabitants in 2004<ref>{{cite web |url=https://www.who.int/healthinfo/global_burden_disease/gbddeathdalycountryestimates2004.xls |title=Death and DALY estimates for 2004 by cause for WHO Member States |format=xls |work=World Health Organization |year=2004 |url-status=live |archive-url=https://web.archive.org/web/20120127191942/http://www.who.int/healthinfo/global_burden_disease/gbddeathdalycountryestimates2004.xls |archive-date=27 January 2012 }}</ref>{{Div col|small=yes|colwidth=10em}}
{{legend|#b3b3b3|no data}}
{{legend|#ffff65|fewer than 20}}
{{legend|#fff200|20–43}}
{{legend|#ffdc00|43–66}}
{{legend|#ffc600|66–89}}
{{legend|#ffb000|89–112}}
{{legend|#ff9a00|112–135}}
{{legend|#ff8400|135–158}}
{{legend|#ff6e00|158–181}}
{{legend|#ff5800|181–204}}
{{legend|#ff4200|204–227}}
{{legend|#ff2c00|227–250}}
{{legend|#cb0000|more than 250}}
{{div col end}}]]

In 2013 for the population aged 40-80 years, the global prevalence of glaucoma was estimated at 3.54%, thus affecting 64.3 million worldwide.<ref name="pmid24974815" /> The same year, 2.97 million people in North America had open-angle glaucoma. By 2040, the prevalence of all types of glaucoma was projected to increase to 111.82 million worldwide and to 4.72 million in North America.<ref name="pmid24974815">{{cite journal| last1=Tham |first1=YC |last2=Li |first2=X |last3=Wong |first3=TY|last4=Quigley |first4=HA|last5=Aung |first5=T|last6=Cheng |first6=CY| title=Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis. | journal=Ophthalmology | year= 2014 | volume= 121 | issue= 11 | pages= 2081–90 | pmid=24974815 | doi=10.1016/j.ophtha.2014.05.013 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24974815  }}</ref>

Globally, glaucoma is the second-leading [[Visual_impairment#Cause|cause of blindness]],<ref name=Man2015/> while [[cataract]]s are a more common cause. In the United States, glaucoma is a leading cause of blindness for African Americans, who have higher rates of primary open-angle glaucoma,<ref>{{cite journal | vauthors = Sommer A, Tielsch JM, Katz J, Quigley HA, Gottsch JD, Javitt JC, Martone JF, Royall RM, Witt KA, Ezrine S | display-authors = 6 | title = Racial differences in the cause-specific prevalence of blindness in east Baltimore | journal = The New England Journal of Medicine | volume = 325 | issue = 20 | pages = 1412–1417 | date = November 1991 | pmid = 1922252 | doi = 10.1056/NEJM199111143252004 | doi-access = free }}</ref><ref>{{cite web |url=http://www.nei.nih.gov/NEWS/statements/marij.asp |publisher=National Eye Institute |title=Glaucoma and Marijuana use |date=21 June 2005 |url-status=dead |archive-url=https://web.archive.org/web/20091227110548/http://www.nei.nih.gov/NEWS/statements/marij.asp |archive-date=27 December 2009 }}</ref> and Hispanic Americans.<ref name="Ou"/><ref name="AAO 2010"/> Bilateral vision loss can negatively affect mobility and interfere with driving.<ref>{{cite journal | vauthors = Ramulu P | title = Glaucoma and disability: which tasks are affected, and at what stage of disease? | journal = Current Opinion in Ophthalmology | volume = 20 | issue = 2 | pages = 92–98 | date = March 2009 | pmid = 19240541 | pmc = 2692230 | doi = 10.1097/ICU.0b013e32832401a9 }}</ref>

A [[meta-analysis]] published in 2009 found that people with primary open-angle glaucoma do not have increased [[mortality rate]]s, or increased risk of cardiovascular death.<ref>{{cite journal | vauthors = Akbari M, Akbari S, Pasquale LR | title = The association of primary open-angle glaucoma with mortality: a meta-analysis of observational studies | journal = Archives of Ophthalmology | volume = 127 | issue = 2 | pages = 204–210 | date = February 2009 | pmid = 19204241 | doi = 10.1001/archophthalmol.2008.571 | doi-access =  }}</ref>

A 2024 ''JAMA Ophthalmology'' article reports that in 2022, an estimated 4.22 million people in the U.S. had glaucoma, with 1.49 million experiencing vision impairment due to the condition, according to a meta-analysis.<ref>{{Cite journal |last1=Ehrlich |first1=Joshua R. |last2=Burke-Conte |first2=Zeb |last3=Wittenborn |first3=John S. |last4=Saaddine |first4=Jinan |last5=Omura |first5=John D. |last6=Friedman |first6=David S. |last7=Flaxman |first7=Abraham D. |last8=Rein |first8=David B. |date=2024-10-17 |title=Prevalence of Glaucoma Among US Adults in 2022 |url=https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2824476 |journal=JAMA Ophthalmology |volume=142 |issue=11 |pages=1046–1053 |language=en |doi=10.1001/jamaophthalmol.2024.3884 |pmid=39418040 |pmc=11581589 |pmc-embargo-date=October 17, 2025 |issn=2168-6165}}</ref> The study found that Black adults were about twice as likely to be affected by glaucoma as White adults. Glaucoma prevalence was 1.62% among individuals aged 18 and older and 2.56% among those aged 40 and older, while vision-affecting glaucoma occurred in 0.57% and 0.91% of these age groups, respectively.<ref>{{Cite web |date=2024-01-10 |title=Glaucoma Facts And Stats - Glaucoma Research Foundation |url=https://glaucoma.org/articles/glaucoma-facts-and-stats?gad_source=1&gclid=CjwKCAjwjsi4BhB5EiwAFAL0YEML0dCrFgRQY2tn9oTD3eNw_yyBoS70ddNfzH5ZyNcrgg41PNyHhBoCi6cQAvD_BwE |access-date=2024-10-18 |language=en-US}}</ref>

==Signs and symptoms==
[[File:Acute Angle Closure-glaucoma.jpg|right|thumb|Photo showing conjunctival vessels dilated at the corneal edge (ciliary flush, circumcorneal flush) and hazy cornea characteristic of acute angle-closure glaucoma]]
{{multiple image
 | direction         = vertical
 | image1            = Eye disease simulation, normal vision.jpg
 | caption1          = A normal range of vision
 | image2            = Eye disease simulation, glaucoma.jpg
 | caption2          = The same view with advanced vision loss from glaucoma
}}
Open-angle glaucoma usually presents with no symptoms early in the course of the disease,<ref name="Stein 2021">{{cite journal |last1=Stein |first1=Joshua D. |last2=Khawaja |first2=Anthony P. |last3=Weizer |first3=Jennifer S. |title=Glaucoma in Adults—Screening, Diagnosis, and Management: A Review |journal=JAMA |date=12 January 2021 |volume=325 |issue=2 |pages=164–174 |doi=10.1001/jama.2020.21899|pmid=33433580 |s2cid=231585520 }}</ref> but it may gradually progress to involve difficulties with vision.<ref name="Stein 2021" /> It usually involves deficits in the peripheral vision followed by central vision loss as the disease progresses, but less commonly it may present as central vision loss or patchy areas of vision loss.<ref name="Stein 2021" /> On an eye examination, optic nerve changes are seen indicating damage to the optic nerve head (increased [[cup-to-disc ratio]] on [[Ophthalmoscopy|fundoscopic examination]]).<ref name="Stein 2021" />

Acute angle-closure glaucoma, a medical emergency due to the risk of impending permanent vision loss, is characterized by sudden ocular pain, seeing halos around lights, [[red eye (medicine)|red eye]], very high [[intraocular pressure]], nausea and vomiting, and suddenly decreased vision.<ref name="Stein 2021" /> Acute angle-closure glaucoma may further present with corneal edema, engorged conjunctival vessels, and a fixed and dilated pupil on examination.<ref name="AAO 1">{{cite web |title=Angle-Closure Glaucoma - American Academy of Ophthalmology |url=https://www.aao.org/education/munnerlyn-laser-surgery-center/angleclosure-glaucoma-19 |website=www.aao.org}}</ref>

Opaque specks may occur in the lens in glaucoma, known as glaukomflecken.<ref>{{cite book| vauthors = Friedman NJ, Kaiser PK, Pineda II R |title=The Massachusetts Eye and Ear Infirmary Illustrated Manual of Ophthalmology E-Book|date=2014|publisher=Elsevier Health Sciences|isbn=978-0-323-22527-4|page=234|url=https://books.google.com/books?id=g8U0AwAAQBAJ&pg=PA234|language=en}}</ref> The word is German, meaning "glaucoma-specks".

==Risk factors==
Glaucoma can affect anyone. Some people have a higher risk or susceptibility to develop glaucoma due to certain [[Risk factor (epidemiology)|risk factor]]s, including increasing age, high intraocular pressure, a family history of glaucoma, and use of steroid medications.<ref name="NIH2016Fact" /> 

=== 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" />

===Family history and genetics===
Positive family history is a risk factor for glaucoma. The relative risk of having primary open-angle glaucoma is increased about two- to four-fold for people who have a sibling with glaucoma.<ref name=yanoff>{{cite book| vauthors = Yanoff M, Duker JS |title=Ophthalmology|year=2009|publisher=Mosby Elsevier|isbn=978-0-323-04332-8|page=1096|edition=3rd}}</ref> Glaucoma, particularly primary open-angle glaucoma, is associated with [[mutation]]s in several [[gene]]s, including ''[[MYOC]], ASB10, [[WDR36]], [[Neurotrophin-4|NTF4]]'', ''[[TANK-binding kinase 1|TBK1]]'',<ref name="OMIM137760">{{OMIM|137760|Glaucoma, Primary Open Angle; POAG}}</ref> and ''[[RPGRIP1]].''<ref>{{cite journal | vauthors = Fernández-Martínez L, Letteboer S, Mardin CY, Weisschuh N, Gramer E, Weber BH, Rautenstrauss B, Ferreira PA, Kruse FE, Reis A, Roepman R, Pasutto F | display-authors = 6 | title = Evidence for RPGRIP1 gene as risk factor for primary open angle glaucoma | journal = European Journal of Human Genetics | volume = 19 | issue = 4 | pages = 445–451 | date = April 2011 | pmid = 21224891 | pmc = 3060327 | doi = 10.1038/ejhg.2010.217 }}</ref> Many of these genes are involved in critical cellular processes that are implicated in the development and progression of glaucoma, including regulation of intraocular pressure, retinal ganglion cell health, and optic nerve function.<ref name="pmid28505344">{{cite journal| author=Wiggs JL, Pasquale LR| title=Genetics of glaucoma. | journal=Hum Mol Genet | year= 2017 | volume= 26 | issue= R1 | pages= R21–R27 | pmid=28505344 | doi=10.1093/hmg/ddx184 | pmc=6074793 }} </ref> Normal-tension glaucoma, which comprises 30-90% of primary open-angle glaucoma (depending on ethnic group),<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> is also associated with genetic mutations (including ''[[OPA1]]'' and ''[[Optineurin|OPTN]]'' genes).<ref>{{OMIM|606657|Glaucoma, Normal Tension, Susceptibility to}}</ref>

Additionally, some rare genetic conditions increase the risk of glaucoma, such as [[Axenfeld–Rieger syndrome|Axenfeld-Rieger syndrome]] and [[primary congenital glaucoma]], which is  associated with mutations in ''[[CYP1B1]]'' or ''[[LTBP2]].''<ref name=":5">{{Cite journal |last1=Badawi |first1=Abdulrahman H. |last2=Al-Muhaylib |first2=Ahmed A. |last3=Al Owaifeer |first3=Adi Mohammed |last4=Al-Essa |first4=Rakan S. |last5=Al-Shahwan |first5=Sami A. |date=2019-10-01 |title=Primary congenital glaucoma: An updated review |journal=Saudi Journal of Ophthalmology |volume=33 |issue=4 |pages=382–388 |doi=10.1016/j.sjopt.2019.10.002 |pmid=31920449 |pmc=6950954 |issn=1319-4534}}</ref> They are inherited in an autosomal recessive fashion.<ref name=":5" /> Axenfeld-Rieger syndrome is inherited in an autosomal dominant fashion and is associated with ''[[PITX2]]'' or [[Forkhead box C1|''FOXC1'']].<ref>{{Citation |last1=Zamora |first1=Edgar A. |title=Axenfeld-Rieger Syndrome |date=2023 |url=http://www.ncbi.nlm.nih.gov/books/NBK538504/ |work=StatPearls |access-date=2023-09-22 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=30860739 |last2=Salini |first2=Baby}}</ref>

===Ethnicity===
The total prevalence of glaucoma is about the same in North America and Asia, but the prevalence of angle-closure glaucoma is four times higher in Asia than in North America.<ref name="pmid24974815"/>

In the United States, glaucoma is more common in African Americans, Latinos, and Asian-Americans.<ref name="Stein 2021" />

===Other===
[[File:Arterial blood flow reversal in neovascular glaucoma.gif |thumb|600px| [[Laser Doppler imaging]] reveals arterial blood flow reversal in neovascular glaucoma. The color change of the Doppler image in the central retinal artery during the cardiac cycle indicates arterial flow reversal.<ref name=Puyo2020Reversal>{{cite arXiv | vauthors = Puyo L, Paques M, Atlan M | title = Retinal blood flow reversal in out-of-plane vessels imaged with laser Doppler holography | date = 2020 | class = physics.med-ph | eprint = 2008.09813}}</ref>]]
Other factors can cause glaucoma, known as "secondary glaucoma", including prolonged use of [[anabolic steroid|steroid]]s (steroid-induced glaucoma); conditions that severely restrict blood flow to the eye, such as severe [[diabetic retinopathy]] and [[central retinal vein occlusion]] (neovascular glaucoma); [[Blast-related ocular trauma|ocular trauma]] (angle-recession glaucoma); [[plateau iris]]; and inflammation of the middle layer of the pigmented vascular eye structure ([[uveitis]]), known as [[uveitic glaucoma]].

==Pathophysiology==
[[File:Human eye cross-sectional view grayscale.png|thumb|Human eye cross-sectional view]]
The main effect of glaucoma is damage to the optic nerve. Eventually, this damage leads to vision loss, which can deteriorate with time. The underlying cause of open-angle glaucoma remains unclear. Several theories exist on its exact etiology. Intraocular pressure is a function of production of liquid aqueous humor by the [[ciliary processes]] of the eye, and its drainage through the trabecular meshwork. Aqueous humor flows from the ciliary processes into the [[posterior chamber]], bounded posteriorly by the [[Lens (anatomy)|lens]] and the [[zonules of Zinn]], and anteriorly by the [[Iris (anatomy)|iris]]. It then flows through the [[pupil]] of the iris into the [[anterior chamber]], bounded posteriorly by the iris and anteriorly by the [[cornea]].

From here, the trabecular meshwork drains aqueous humor via the scleral venous sinus ([[Schlemm's canal]]) into [[Intrascleral plexus|scleral plexuses]] and general blood circulation.<ref name=Alguire>{{cite book | vauthors = Alguire P |chapter=The Eye Chapter 118 Tonometry>Basic Science|veditors=Walker HK, Hall WD, Hurst JW |title=Clinical methods: the history, physical, and laboratory examinations |publisher=Butterworths|location=London |year=1990 |pmid=21250045 |isbn=978-0-409-90077-4 |edition=3rd |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK201/?partid=222#A3607}}</ref>

In open/wide-angle glaucoma, flow is reduced through the trabecular meshwork, due to the degeneration and obstruction of the trabecular meshwork, whose original function is to absorb the aqueous humor. Loss of aqueous humor absorption leads to increased resistance and thus a chronic, painless buildup of pressure in the eye.<ref name=Mozaffarieh2008>{{cite journal | vauthors = Mozaffarieh M, Grieshaber MC, Flammer J | title = Oxygen and blood flow: players in the pathogenesis of glaucoma | journal = Molecular Vision | volume = 14 | pages = 224–233 | date = January 2008 | pmid = 18334938 | pmc = 2267728 }}</ref>

In primary angle-closure glaucoma, the iridocorneal angle is narrowed or completely closed, obstructing the flow of aqueous humor to the trabecular meshwork for drainage. This is usually due to the forward displacement of the iris against the cornea, resulting in angle closure. This accumulation of aqueous humor causes an acute increase in pressure and damage to the optic nerve.<ref name="Stein 2021" />

The pathophysiology of glaucoma is not well understood. Several theories exist regarding the mechanism of the damage to the optic nerve in glaucoma. The biomechanical theory hypothesizes that the retinal ganglion-cell axons (which form the optic nerve head and the retinal nerve fiber layer) are particularly susceptible to mechanical damage from increases in the intraocular pressure as they pass through pores at the [[Lamina cribrosa sclerae|lamina cribrosa]]. Thus, increases in intraocular pressure would cause nerve damage as seen in glaucoma.<ref name="Stein 2021" /> The vascular theory hypothesizes that a decreased blood supply to the retinal ganglions cells leads to nerve damage. This decrease in blood supply may be due to increasing intraocular pressures, and may also be due to systemic hypotension, vasospasm, or atherosclerosis.<ref name="Stein 2021" /> This is supported by evidence that those with low blood pressure, particularly low diastolic blood pressure, are at an increased risk of glaucoma.<ref name="Stein 2021" /> 

The primary neurodegeneration theory hypothesizes that a primary neurodegenerative process may be responsible for degeneration at the optic nerve head in glaucoma.<ref name="Stein 2021" /> This would be consistent with a possible mechanism of normal tension glaucoma (those with open-angle glaucoma with normal eye pressures) and is supported by evidence showing a correlation of glaucoma with [[Alzheimer's dementia]] and other causes of cognitive decline.<ref name="Helmer 2013">{{cite journal |last1=Helmer |first1=Catherine |last2=Malet |first2=Florence |last3=Rougier |first3=Marie-Bénédicte |last4=Schweitzer |first4=Cédric |last5=Colin |first5=Joseph |last6=Delyfer |first6=Marie-Noëlle |last7=Korobelnik |first7=Jean-François |last8=Barberger-Gateau |first8=Pascale |last9=Dartigues |first9=Jean-François |last10=Delcourt |first10=Cécile |title=Is there a link between open-angle glaucoma and dementia?: The Three-City-Alienor Cohort |journal=Annals of Neurology |date=September 2013 |volume=74 |issue=2 |pages=171–179 |doi=10.1002/ana.23926|pmid=23686609 |s2cid=28166631 }}</ref><ref name="Ko 2018">{{cite journal |last1=Ko |first1=Fang |last2=Muthy |first2=Zaynah A. |last3=Gallacher |first3=John |last4=Sudlow |first4=Cathie |last5=Rees |first5=Geraint |last6=Yang |first6=Qi |last7=Keane |first7=Pearse A. |last8=Petzold |first8=Axel |last9=Khaw |first9=Peng T. |last10=Reisman |first10=Charles |last11=Strouthidis |first11=Nicholas G. |last12=Foster |first12=Paul J. |last13=Patel |first13=Praveen J. |title=Association of Retinal Nerve Fiber Layer Thinning With Current and Future Cognitive Decline: A Study Using Optical Coherence Tomography |journal=JAMA Neurology |date=1 October 2018 |volume=75 |issue=10 |pages=1198–1205 |doi=10.1001/jamaneurol.2018.1578|pmid=29946685 |pmc=6233846 }}</ref>
Both experimental and clinical studies implicate that [[oxidative stress]] plays a role in the pathogenesis of open-angle glaucoma<ref>{{Cite journal|title=Lipid peroxidation: pathophysiological and pharmacological implications in the eye|first1=Ya Fatou|last1=Njie-Mbye|first2=Madhura|last2=Chitnis|first3=Catherine|last3=Opere|first4=Sunny|last4=Ohia|date=17 January 2013|journal=Frontiers in Physiology|volume=4|page=366 |doi=10.3389/fphys.2013.00366|doi-access=free |pmid=24379787 |pmc=3863722}}</ref> as well as in Alzheimer's disease.<ref>{{Cite journal |last1=Ryan |first1=Sean K. |last2=Ugalde |first2=Cathryn L. |last3=Rolland |first3=Anne-Sophie |last4=Skidmore |first4=John |last5=Devos |first5=David |last6=Hammond |first6=Timothy R. |date=2023 |title=Therapeutic inhibition of ferroptosis in neurodegenerative disease |journal=Trends in Pharmacological Sciences |volume=44 |issue=10 |pages=674–688 |doi=10.1016/j.tips.2023.07.007 |pmid=37657967|doi-access=free }}</ref>

Degeneration of [[axon]]s of the [[retinal ganglion cell]]s (the optic nerve) is a hallmark of glaucoma.<ref name="pmid32454935">{{cite journal | vauthors = Jadeja RN, Thounaojam MC, Bartoli M, Martin PM | title = Implications of NAD<sup>+</sup> Metabolism in the Aging Retina and Retinal Degeneration | journal = Oxidative Medicine and Cellular Longevity | volume = 2020 | pages = 2692794 | date = 2020 | pmid = 32454935 | pmc = 7238357 | doi = 10.1155/2020/2692794 | doi-access = free }}</ref> The inconsistent relationship of glaucomatous [[optic neuropathy]] with increased intraocular pressure has provoked hypotheses and studies on anatomic structure, eye development, nerve compression trauma, optic nerve blood flow, excitatory neurotransmitter, trophic factor, retinal ganglion cell or axon degeneration, glial support cell, immune system, aging mechanisms of neuron loss, and severing of the nerve fibers at the scleral edge.<ref>{{cite journal |last1=Hasnain |first1=Syed S. |title=Scleral edge, not optic disc or retina, is the primary site of injury in chronic glaucoma |journal=Medical Hypotheses |date=2006 |volume=67 |issue=6 |pages=1320–1325 |doi=10.1016/j.mehy.2006.05.030 |pmid=16824694 |url=https://pubmed.ncbi.nlm.nih.gov/16824694/}}</ref><ref>{{cite journal | vauthors = Osborne NN, Wood JP, Chidlow G, Bae JH, Melena J, Nash MS | title = Ganglion cell death in glaucoma: what do we really know? | journal = The British Journal of Ophthalmology | volume = 83 | issue = 8 | pages = 980–986 | date = August 1999 | pmid = 10413706 | pmc = 1723166 | doi = 10.1136/bjo.83.8.980 }}</ref><ref name=Levin2008>{{cite journal | vauthors = Levin LA, Peeples P | title = History of neuroprotection and rationale as a therapy for glaucoma | journal = The American Journal of Managed Care | volume = 14 | issue = 1 Suppl | pages = S11–S14 | date = February 2008 | pmid = 18284310 }}</ref><ref name=Varma2008>{{cite journal | vauthors = Varma R, Peeples P, Walt JG, Bramley TJ | title = Disease progression and the need for neuroprotection in glaucoma management | journal = The American Journal of Managed Care | volume = 14 | issue = 1 Suppl | pages = S15–S19 | date = February 2008 | pmid = 18284311 }}</ref><ref name=Hernandez2008>{{cite journal | vauthors = Hernández M, Urcola JH, Vecino E | title = Retinal ganglion cell neuroprotection in a rat model of glaucoma following brimonidine, latanoprost or combined treatments | journal = Experimental Eye Research | volume = 86 | issue = 5 | pages = 798–806 | date = May 2008 | pmid = 18394603 | doi = 10.1016/j.exer.2008.02.008 }}</ref><ref name=Knox2007>{{cite journal | vauthors = Knox DL, Eagle RC, Green WR | title = Optic nerve hydropic axonal degeneration and blocked retrograde axoplasmic transport: histopathologic features in human high-pressure secondary glaucoma | journal = Archives of Ophthalmology | volume = 125 | issue = 3 | pages = 347–353 | date = March 2007 | pmid = 17353405 | doi = 10.1001/archopht.125.3.347 | doi-access =  }}</ref><ref name="CanJOphth42-3-3">{{cite journal |title=Issue on neuroprotection |journal=Can. J. Ophthalmol. |volume=42 |issue=3 |date=June 2007 |issn=1715-3360 |url=http://pubs.nrc-cnrc.gc.ca/cjo/cjo42-03.html |url-status=dead |archive-url=https://archive.today/20070512122154/http://pubs.nrc-cnrc.gc.ca/cjo/cjo42-03.html |archive-date=12 May 2007 }}{{page needed|date=June 2021}}</ref>

==Diagnosis==
[[File:Glaukompapille2.jpg|thumb|Optic nerve in advanced glaucoma disease]]
[[File:Optic disc topography, case 1, R, glaucoma.png|thumb|Glaucoma (right eye) with significant optic disc involvement. 80-year-old man. Optic disc topography.]]
Screening for glaucoma is an integral part of a standard eye examination performed by optometrists and ophthalmologists.<ref name="mayo22">{{cite web |title=Glaucoma diagnosis |url=https://www.mayoclinic.org/diseases-conditions/glaucoma/diagnosis-treatment/drc-20372846 |publisher=Mayo Clinic |access-date=22 September 2023 |date=30 September 2022}}</ref> The workup for glaucoma involves taking a thorough case history, with the emphasis on assessment of risk factors. 

The baseline glaucoma evaluation tests include intraocular pressure measurement by using tonometry, [[anterior chamber angle]] assessment by [[optical coherence tomography]], inspecting the drainage angle ([[gonioscopy]]), and [[retinal nerve fiber layer]] assessment with a [[fundus (eye)|fundus]] examination, measuring corneal thickness ([[pachymetry]]), and [[visual field]] [[Perimetry|testing]].<ref name=mayo22/>

=== Types ===
{{More citations needed section|date=August 2015}}
Glaucoma has been classified into specific types:<ref name="Paton">{{cite journal |vauthors=Paton D, Craig JA |year=1976 |title=Glaucomas. Diagnosis and management |journal=Clinical Symposia |volume=28 |issue=2 |pages=1–47 |pmid=1053095}}</ref>

===Primary glaucoma and its variants===
Primary glaucoma (H40.1-H40.2) includes primary open-angle glaucoma (chronic open-angle, chronic simple, glaucoma simplex) which can be high-tension or low-tension, and primary angle closure glaucoma (primary closed-angle, narrow-angle, pupil-block, acute congestive), which can manifest as acute, chronic, intermittent, or superimposed on chronic open-angle closure glaucoma (also called "combined mechanism" glaucoma).

Other variants of primary glaucoma include:
*[[Pigment dispersion syndrome|Pigmentary glaucoma]]
*[[Exfoliation glaucoma]], also known as pseudoexfoliative glaucoma or glaucoma capsulare
*[[Primary juvenile glaucoma]]

'''Primary angle closure glaucoma''' is caused by contact between the iris and trabecular meshwork, which in turn obstructs outflow of the aqueous humor from the eye. This contact between iris and trabecular meshwork (TM) may gradually damage the function of the meshwork until it fails to keep pace with aqueous production, and the pressure rises. In over half of all cases, prolonged contact between iris and TM causes the formation of synechiae (effectively "scars").

These cause permanent obstruction of aqueous outflow. In some cases, pressure may rapidly build up in the eye, causing pain and redness (symptomatic, or so-called "acute"-angle closure). In this situation, the vision may become blurred, and halos may be seen around bright lights. Accompanying symptoms may include a headache and vomiting.

Diagnosis is made from physical signs and symptoms - pupils mid-dilated and unresponsive to light, cornea edematous (cloudy), reduced vision, redness, and pain. However, the majority of cases are asymptomatic. Prior to the very severe loss of vision, these cases can only be identified by examination, generally by an eye-care professional.

===Developmental glaucoma===
Developmental glaucoma (Q15.0)
*[[Primary congenital glaucoma]]
*Infantile glaucoma
*Glaucoma associated with hereditary or familial diseases

===Secondary glaucoma===
[[Secondary glaucoma]] (H40.3-H40.6) encompasses numerous subtypes: inflammatory glaucoma (all types of uveitis, Fuchs heterochromic iridocyclitis); phacogenic glaucoma (angle-closure with mature [[cataract]], phacoanaphylactic glaucoma from [[lens capsule]] rupture, [[phacolytic glaucoma]], [[lens subluxation]]); glaucoma secondary to intraocular hemorrhage ([[hyphema]], [[Hemolysis|hemolytic]]/erythroclastic glaucoma); traumatic glaucoma (angle recession glaucoma); postsurgical glaucoma (aphakic pupillary block, ciliary block); neovascular glaucoma; drug-induced glaucoma (corticosteroid-induced, alpha-chymotrypsin); and glaucoma of miscellaneous origin (associated with [[Eye neoplasm|intraocular tumors]], [[Retinal detachment|retinal detachments]], severe chemical burns, [[essential iris atrophy]], or toxic glaucoma).

'''Neovascular glaucoma''', an uncommon type of glaucoma, is difficult or nearly impossible to treat, and is often caused by proliferative [[diabetic retinopathy]] (PDR) or [[central retinal vein occlusion]] (CRVO). It may also be triggered by other conditions that result in [[ischemia]] of the [[retina]] or [[ciliary body]]. Individuals with poor blood flow to the eye are highly at risk for this condition.

Neovascular glaucoma results when new, abnormal vessels begin developing in the angle of the eye that begin blocking the drainage. People with such condition begin to rapidly lose their eyesight. Sometimes, the disease appears very rapidly, especially after cataract surgery procedures.

'''Toxic glaucoma''' is open-angle glaucoma with an unexplained significant rise of intraocular pressure following unknown pathogenesis. Intraocular pressure can sometimes reach {{convert|80|mmHg|abbr=on}}. It characteristically manifests as ciliary body inflammation and massive trabecular edema that sometimes extends to Schlemm's canal. This condition is differentiated from malignant glaucoma by the presence of a deep and clear anterior chamber and a lack of aqueous misdirection. Also, the corneal appearance is not as hazy. A reduction in visual acuity can occur followed neuroretinal breakdown.

===Absolute glaucoma===
Absolute glaucoma (H44.5) is the end stage of all types of glaucoma. The eye has no vision, absence of [[pupillary light reflex]] and [[pupillary response]], and has a stony appearance. Severe pain is present in the eye. The treatment of absolute glaucoma is a destructive procedure like cyclocryoapplication, cyclophotocoagulation, or injection of 99% alcohol.

==Visual field defects in glaucoma==
{{see also|Visual field}}
[[File:Bjerrums area and types of scotomas on the visual field.png|thumb|Bjerrums area and types of scotomas on the visual field]]
In glaucoma visual field defects result from damage to the [[retinal nerve fiber layer]] (RNFL). Field defects are seen mainly in primary open angle glaucoma. Because of the unique anatomy of the RNFL, many noticeable patterns are seen in the visual field. Most of the early glaucomatous changes are seen within the central visual field, mainly in Bjerrum's area, 10-20° from fixation.<ref name="Parson-GL">{{cite book |title=Parsons' diseases of the eye |publisher=Elsevier |isbn=978-81-312-3818-9 |pages=288–295 |edition=22nd |chapter=Glaucoma|date=15 July 2015 }}</ref>

Following are the common glaucomatous field defects:

* '''Generalized depression''': Generalized depression is seen in early stages of glaucoma and many other conditions. Mild constriction of central and peripheral visual field due to isopter contraction comes under generalized depression. If all the isopters show similar depression to the same point, it is then called a contraction of visual field. Relative paracentral scotomas are the areas where smaller and dimmer targets are not visualized by the patient.<ref name="Parson-GL" /> Larger and brighter targets can be seen. Small paracentral depressions, mainly superonasal are seen in normal tension glaucoma (NTG).<ref name="Kanski-GL">{{cite book | vauthors = Salmon JF |title=Kanski's Clinical ophthalmology |publisher=Elsevier |edition=9th |chapter=Glaucoma|pages=362–365}}</ref> The generalized depression of the entire field may be seen in cataract also.<ref name="Eyerounds">{{cite web | vauthors = Carroll JN, Johnson CA |title=Visual Field Testing: From One Medical Student to Another |url=https://eyerounds.org/tutorials/VF-testing/ |date=2013-08-22}}</ref>
* '''Baring of blind spot''': "Baring of blind spot" means exclusion of blind spot from the central field due to inward curve of the outer boundary of 30° central field.<ref name="Khurana-GL">{{cite book | vauthors = Khurana AK, Khurana B|title=Comprehensive ophthalmology |publisher=Jaypee, The Health Sciences Publisher |isbn=978-93-5152-657-5 |pages=223–224 |edition=6th |chapter=Glaucoma|date=31 August 2015 }}</ref> It is only an early non-specific visual field change, without much diagnostic value in glaucoma.<ref name="Khurana-GL"/>
* '''Small wing-shaped Paracentral scotoma''': Small wing-shaped Paracentral scotoma within Bjerrum's area is the earliest clinically significant field defect seen in glaucoma. It may also be associated with nasal steps. Scotoma may be seen above or below the blind spot.<ref name="Khurana-GL"/>
* '''Siedel's sickle-shaped scotoma''': Paracentral scotoma joins with the [[Blind spot (vision)|blind spot]] to form the [[Seidel sign]]. 
* '''Arcuate or Bjerrum's scotoma''':[[File:Visual field arcuate scotoma.png|thumb|Arcuate scotoma]]  It is formed at later stages of glaucoma by extension of Seidel's scotoma in an area either above or below the fixation point to reach the horizontal line. Peripheral breakthrough may occur due to damage of nerve fibers.<ref name="Khurana-GL"/>
* '''Ring or Double arcuate scotoma''': Two arcuate scotomas join to form a Ring or Double arcuate scotoma. This defect is seen in advanced stages of glaucoma.
* '''Roenne's central nasal step''': It is created when two arcuate scotomas run in different arcs to form a right angled defect. This is also seen in advanced stages of glaucoma.
* '''Peripheral field defects''': Peripheral field defects may occur in early or late stages of glaucoma. Roenne's peripheral nasal steps occur due to contraction of peripheral isopter.<ref name="Khurana-GL"/>
* '''Tubular vision''': [[File:Eye disease simulation, retinitis pigmentosa.jpg|thumb|Tubular vision]] Since macular fibers are the most resistant to glaucomatous damage, the central vision remains unaffected until end stages of glaucoma. Tubular vision or [[Tunnel vision]] is the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision. It is seen in the end stages of glaucoma. [[Retinitis pigmentosa]] is another disease that causes tubular vision.<ref>{{cite web|title = Retinitis pigmentosa|url = http://ghr.nlm.nih.gov/condition/retinitis-pigmentosa|website = Genetics Home Reference}}</ref>
* '''Temporal island of vision''': It is also seen in end stages of glaucoma. The temporal islands lie outside of the central 24 to 30° visual field,<ref>{{cite web | vauthors = Themes UF |title=Visual Fields in Glaucoma |url=https://entokey.com/visual-fields-in-glaucoma/#:~:text=The%20typical%20visual%20field%20in,24%20to%2030%C2%B0%C2%B0 |website=Ento Key |date=11 July 2016}}</ref> so it may not be visible with standard central field measurements done in glaucoma.

==Screening==
The [[United States Preventive Services Task Force]] stated, as of 2013, that there was insufficient evidence to recommend for or against screening for glaucoma.<ref>{{cite journal | vauthors =  | title = Summaries for patients. Screening for glaucoma: U.S. Preventive Services Task Force recommendation statement | journal = Annals of Internal Medicine | volume = 159 | issue = 7 | pages = I-28 | date = October 2013 | pmid = 23836133 | doi = 10.7326/0003-4819-159-6-201309170-00685 | doi-access =  | s2cid = 219991894 }}</ref> Therefore, there is no national screening program in the US. Screening, however, is recommended starting at age 40 by the American Academy of Ophthalmology.<ref name=Man2015/>

There is no screening program in the UK, however opportunistic testing is recommended for at-risk groups, including free eye tests.<ref>{{Cite journal |last=Hamid |first=Sana |last2=Desai |first2=Parul |last3=Hysi |first3=Pirro |last4=Burr |first4=Jennifer M. |last5=Khawaja |first5=Anthony P. |date=2021-08-03 |title=Population screening for glaucoma in UK: current recommendations and future directions |url=https://www.nature.com/articles/s41433-021-01687-8 |journal=Eye |language=en |volume=36 |issue=3 |pages=504–509 |doi=10.1038/s41433-021-01687-8 |issn=1476-5454 |pmc=8873198 |pmid=34345031}}</ref><ref>{{Cite web |last=Court |first=Molly |date=2025-02-23 |title=Who is eligible for a free NHS-funded eye test? Full list |url=https://www.westerntelegraph.co.uk/news/24955939.eligible-free-nhs-funded-eye-test-full-list/ |access-date=2025-05-07 |website=Western Telegraph}}</ref>

{{anchor|Management}} <!-- This avoids broken links from articles section-linking to the old section name.  See WP:ANCHOR. -->

==Treatment==
The goal of glaucoma management for patients with increased intraocular pressure is to decrease the intraocular pressure (IOP), thus slowing the progression of glaucoma and preserving the quality of life for patients, with minimal side-effects.<ref name=Necker2006>{{cite journal | vauthors = Noecker RJ | title = The management of glaucoma and intraocular hypertension: current approaches and recent advances | journal = Therapeutics and Clinical Risk Management | volume = 2 | issue = 2 | pages = 193–206 | date = June 2006 | pmid = 18360593 | pmc = 1661659 | doi = 10.2147/tcrm.2006.2.2.193 | doi-access = free }}</ref><ref name=Parikh2007>{{cite journal | vauthors = Parikh RS, Parikh SR, Navin S, Arun E, Thomas R | title = Practical approach to medical management of glaucoma | journal = Indian Journal of Ophthalmology | volume = 56 | issue = 3 | pages = 223–230 | date = 1 May 2008 | pmid = 18417824 | pmc = 2636120 | doi = 10.4103/0301-4738.40362 | doi-access = free }}</ref><ref name=":4"/> This requires appropriate diagnostic techniques and follow-up examinations, and judicious selection of treatments for the individual patient. Although increased IOP is only one of the major risk factors for glaucoma, lowering it via various pharmaceuticals and/or surgical techniques is currently the mainstay of glaucoma treatment. 

Vascular flow and neurodegenerative theories of glaucomatous optic neuropathy have prompted studies on various neuroprotective therapeutic strategies, including nutritional compounds, some of which may be regarded by clinicians as safe for use now, while others are on trial.<ref name="DOI10.1016/B978-0-323-88442-6.00039-X">Yu Jun Wo, Ching‐Yu Cheng, Rachel S. Chong: ''Vascular health and glaucoma.'' In: Kevin Gillmann, Kaweh Mansouri (Eds.): ''The Science of Glaucoma Management. From Translational Research to Next-Generation Clinical Practice'', Elsevier 2023, ISBN 978-0-323-88443-3, p.&nbsp;63–79, {{doi|10.1016/B978-0-323-88442-6.00039-X}}, [https://books.google.com/books?id=Sn-HEAAAQBAJ&dq=glaucoma+%22vascular+health%22&pg=PA74 preview Google Books].</ref><ref name="pmid34575340">{{cite journal| author=Konieczka K, Flammer J| title=Treatment of Glaucoma Patients with Flammer Syndrome. | journal=J Clin Med | year= 2021 | volume= 10 | issue= 18 | page=4227 | pmid=34575340 | doi=10.3390/jcm10184227 | doi-access=free | pmc=8467118 }} </ref><ref name="pmid32282348">{{cite journal |author1=Labkovich M |author2=Jacobs EB |author3=Bhargava S |author4=Pasquale LR |author5=Ritch R | title=Ginkgo Biloba Extract in Ophthalmic and Systemic Disease, With a Focus on Normal-Tension Glaucoma. | journal=Asia Pac J Ophthalmol (Phila) | year= 2020 | volume= 9 | issue= 3 | pages= 215–225 | pmid=32282348 | doi=10.1097/APO.0000000000000279 | pmc=7299225 }} </ref> Mental stress is also considered as consequence and cause of vision loss which means that stress management training, [[autogenic training]] and other techniques to cope with stress can be helpful.<ref>{{cite journal | vauthors = Sabel BA, Wang J, Cárdenas-Morales L, Faiq M, Heim C | title = Mental stress as consequence and cause of vision loss: the dawn of psychosomatic ophthalmology for preventive and personalized medicine | journal = The EPMA Journal | volume = 9 | issue = 2 | pages = 133–160 | date = June 2018 | pmid = 29896314 | pmc = 5972137 | doi = 10.1007/s13167-018-0136-8 }}</ref><ref name="pmid26449918">{{cite journal| author=Bertelmann T, Strempel I| title=[Self-relaxation techniques for glaucoma patients. Significance of autogenic training, hypnosis and music therapy]. | journal=Ophthalmologe | year= 2016 | volume= 113 | issue= 2 | pages= 102–10 | pmid=26449918 | doi=10.1007/s00347-015-0139-y | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26449918  }} </ref>

===Medication===
{{Main|Glaucoma medication}}
There are several pressure-lowering medication groups that could be used in lowering the IOP, usually eyedrops. The choice of medication usually depends on the dose, duration and the side effects of each medication. However, in general, [[prostaglandin analogue]]s are the first-line treatment for glaucoma.<ref name=":4">{{Cite journal |last1=Weinreb |first1=Robert N. |last2=Aung |first2=Tin |last3=Medeiros |first3=Felipe A. |date=2014-05-14 |title=The Pathophysiology and Treatment of Glaucoma: A Review |journal=JAMA |language=en |volume=311 |issue=18 |pages=1901–1911 |doi=10.1001/jama.2014.3192 |pmid=24825645 |pmc=4523637 |issn=0098-7484}}</ref><ref name=":3">{{Cite journal |last1=Schuster |first1=Alexander K. |last2=Erb |first2=Carl |last3=Hoffmann |first3=Esther M. |last4=Dietlein |first4=Thomas |last5=Pfeiffer |first5=Norbert |date=2020-03-27 |title=The Diagnosis and Treatment of Glaucoma |journal=Deutsches Ärzteblatt International |volume=117 |issue=13 |pages=225–234 |doi=10.3238/arztebl.2020.0225 |pmid=32343668 |pmc=7196841 |issn=1866-0452}}</ref>

Prostaglandin analogues, such as [[latanoprost]], [[bimatoprost]] and [[travoprost]], reduce the IOP by increasing the aqueous fluid outflow through the draining angle. It is usually prescribed once daily at night. The systemic side effects of this class are minimal. However, they can cause local side effects including redness of the conjunctiva, change in the iris color and eyelash elongation.<ref name=":4" /><ref name=":3" />

There are several other classes of medications that could be used as a second-line in case of treatment failure or presence of contraindications to prostaglandin analogues.<ref>{{Cite journal |last1=Wagner |first1=Isabella V. |last2=Stewart |first2=Michael W. |last3=Dorairaj |first3=Syril K. |date=December 2022 |title=Updates on the Diagnosis and Management of Glaucoma |journal=Mayo Clinic Proceedings: Innovations, Quality & Outcomes |language=en |volume=6 |issue=6 |pages=618–635 |doi=10.1016/j.mayocpiqo.2022.09.007|pmid=36405987 |pmc=9673042 }}</ref><ref name=":3" /> These include:

* Topical [[beta-adrenergic receptor antagonists]], such as [[timolol]], [[levobunolol]], and [[betaxolol]], decrease aqueous humor production by the epithelium of the [[ciliary body]].
* [[Alpha2-adrenergic agonist]]s, such as [[brimonidine]] and [[apraclonidine]], work by a dual mechanism, decreasing aqueous humor production and increasing uveoscleral outflow.
* Less-selective [[Alpha-adrenergic agonist|alpha agonists]], such as [[epinephrine]], decrease aqueous humor production through vasoconstriction of ciliary body blood vessels, useful only in open-angle glaucoma. Epinephrine's mydriatic effect, however, renders it unsuitable for closed-angle glaucoma due to further narrowing of the uveoscleral outflow (i.e. further closure of trabecular meshwork, which is responsible for absorption of aqueous humor).
* [[Miosis|Miotic agents]] ([[parasympathomimetic]]s), such as [[pilocarpine]], work by contraction of the [[ciliary muscle]], opening the [[trabecular meshwork]] and allowing increased outflow of the aqueous humour. [[Echothiophate]], an acetylcholinesterase inhibitor, is used in chronic glaucoma.
* [[Carbonic anhydrase inhibitors]], such as [[dorzolamide]], [[brinzolamide]], and [[acetazolamide]], lower secretion of aqueous humor by inhibiting carbonic anhydrase in the ciliary body.

Each of these medicines may have local and systemic side effects. Wiping the eye with an absorbent pad after the administration of eye drops may result in fewer adverse effects.<ref name="Xu">{{cite journal | vauthors = Xu L, Wang X, Wu M | title = Topical medication instillation techniques for glaucoma | journal = The Cochrane Database of Systematic Reviews | volume = 2017 | issue = 2 | pages = CD010520 | date = February 2017 | pmid = 28218404 | pmc = 5419432 | doi = 10.1002/14651858.CD010520.pub2 }}</ref> Initially, glaucoma drops may reasonably be started in either one or in both eyes.<ref name="BMC Ophthalmol">{{cite journal | vauthors = Leffler CT, Amini L | title = Interpretation of uniocular and binocular trials of glaucoma medications: an observational case series | journal = BMC Ophthalmology | volume = 7 | pages = 17 | date = October 2007 | pmid = 17916260 | pmc = 2093925 | doi = 10.1186/1471-2415-7-17 | doi-access = free }}</ref>

==== Adherence ====
Poor [[Adherence (medicine)|compliance with medications]] and follow-up visits is a major reason for treatment failure and disease progression in glaucoma patients. Poor adherence could lead to increased complication rates, thus increasing the need of non-pharmacological interventions including surgery. Patient education and communication must be ongoing to sustain successful treatment plans for this lifelong disease with no early symptoms.<ref>{{Cite journal |last1=Quaranta |first1=Luciano |last2=Novella |first2=Alessio |last3=Tettamanti |first3=Mauro |last4=Pasina |first4=Luca |last5=Weinreb |first5=Robert N. |last6=Nobili |first6=Alessandro |date=October 2023 |title=Adherence and Persistence to Medical Therapy in Glaucoma: An Overview |journal=Ophthalmology and Therapy |language=en |volume=12 |issue=5 |pages=2227–2240 |doi=10.1007/s40123-023-00730-z |pmid=37311908 |pmc=10441906 |issn=2193-8245}}</ref>

===Laser===
Argon laser [[trabeculoplasty]] (ALT) may be used to treat open-angle glaucoma, but this is a temporary solution, not a cure. A 50-μm argon laser spot is aimed at the trabecular meshwork to stimulate the opening of the mesh to allow more outflow of aqueous fluid. Usually, half of the angle is treated at a time. Traditional laser trabeculoplasty uses a thermal argon laser in an [[argon]] laser trabeculoplasty procedure.

Nd:YAG laser peripheral iridotomy (LPI) may be used in patients susceptible to or affected by angle closure glaucoma or [[pigment dispersion syndrome]]. During laser iridotomy, laser energy is used to make a small, full-thickness opening in the iris to equalize the pressure between the front and back of the iris, thus correcting any abnormal bulging of the iris. In people with narrow angles, this can uncover the trabecular meshwork. In some cases of intermittent or short-term angle closure, this may lower the eye pressure. Laser iridotomy reduces the risk of developing an attack of acute angle closure. In most cases, it also reduces the risk of developing chronic angle closure or of adhesions of the iris to the trabecular meshwork. [[Computational fluid dynamics]] (CFD) simulations have shown that an optimal iridotomy size to relieve the pressure differential between the anterior and posterior side of the iris is around 0.1&nbsp;mm to 0.2&nbsp;mm.<ref>{{Cite journal |last1=Cai |first1=Jian-Cheng |last2=Chen |first2=Yan-Ling |last3=Cao |first3=Yue-Hong |last4=Babenko |first4=Andrii |last5=Chen |first5=Xi |date=2022-02-01 |title=Numerical study of aqueous humor flow and iris deformation with pupillary block and the efficacy of laser peripheral iridotomy |url=https://www.sciencedirect.com/science/article/pii/S0268003322000092 |journal=Clinical Biomechanics |language=en |volume=92 |pages=105579 |doi=10.1016/j.clinbiomech.2022.105579 |pmid=35085976 |s2cid=246361118 |issn=0268-0033|url-access=subscription }}</ref> This coincides with clinical practice of LPI where an iridotomy size of 150 to 200 microns is commonly used. However, larger iriditomy sizes are sometimes necessary.

===Surgery===
[[File:Conventional surgery to treat glaucoma EDA11.JPG|thumb|Conventional surgery to treat glaucoma makes a new opening in the [[trabecular meshwork]], which helps fluid to leave the eye and lowers intraocular pressure.]]
{{Main|Glaucoma surgery}}

Both [[Laser surgery|laser]] and conventional surgeries are performed to treat glaucoma. Surgery is the primary therapy for those with [[congenital]] glaucoma.<ref>{{OMIM|231300|Glaucoma, Congenital: GLC3 Buphthalmos}}</ref> Generally, these operations are a temporary solution, as there is not yet a cure for glaucoma.

====Canaloplasty====
[[Canaloplasty]] is a nonpenetrating procedure using micro[[catheter]] technology. To perform a canaloplasty, an incision is made into the eye to gain access to the [[Schlemm's canal]] in a similar fashion to a viscocanalostomy. A microcatheter will circumnavigate the canal around the iris, enlarging the main drainage channel and its smaller collector channels through the injection of a sterile, gel-like material called [[viscoelastic]]. The catheter is then removed and a suture is placed within the canal and tightened.

By opening the canal, the pressure inside the eye may be relieved, although the reason is unclear, since the canal (of Schlemm) does not have any significant fluid resistance in glaucoma or healthy eyes. Long-term results are not available.<ref>{{cite journal | vauthors = Shingleton B, Tetz M, Korber N | title = Circumferential viscodilation and tensioning of Schlemm canal (canaloplasty) with temporal clear corneal phacoemulsification cataract surgery for open-angle glaucoma and visually significant cataract: one-year results | journal = Journal of Cataract and Refractive Surgery | volume = 34 | issue = 3 | pages = 433–440 | date = March 2008 | pmid = 18299068 | doi = 10.1016/j.jcrs.2007.11.029 | s2cid = 23904366 }}</ref><ref>{{cite journal | vauthors = Lewis RA, von Wolff K, Tetz M, Korber N, Kearney JR, Shingleton B, Samuelson TW | title = Canaloplasty: circumferential viscodilation and tensioning of Schlemm's canal using a flexible microcatheter for the treatment of open-angle glaucoma in adults: interim clinical study analysis | journal = Journal of Cataract and Refractive Surgery | volume = 33 | issue = 7 | pages = 1217–1226 | date = July 2007 | pmid = 17586378 | doi = 10.1016/j.jcrs.2007.03.051 | s2cid = 36397585 }}</ref>

====Trabeculectomy====
The most common conventional surgery performed for glaucoma is the [[trabeculectomy]]. Here, a partial thickness flap is made in the scleral wall of the eye, and a window opening is made under the flap to remove a portion of the trabecular meshwork. The scleral flap is then sutured loosely back in place to allow fluid to flow out of the eye through this opening, resulting in lowered intraocular pressure and the formation of a bleb or fluid bubble on the surface of the eye.

Scarring can occur around or over the flap opening, causing it to become less effective or lose effectiveness altogether. Traditionally, chemotherapeutic adjuvants, such as [[mitomycin C]] (MMC) or [[5-fluorouracil]] (5-FU), are applied with soaked sponges on the wound bed to prevent filtering blebs from scarring by inhibiting fibroblast proliferation. Contemporary alternatives to prevent the scarring of the meshwork opening include the sole or combinative implementation of nonchemotherapeutic adjuvants such as the Ologen collagen matrix, which has been clinically shown to increase the success rates of surgical treatment.<ref>{{cite journal | vauthors = Dada T, Sharma R, Sinha G, Angmo D, Temkar S | title = Cyclodialysis-enhanced trabeculectomy with triple Ologen implantation | journal = European Journal of Ophthalmology | volume = 26 | issue = 1 | pages = 95–97 | year = 2016 | pmid = 26044372 | doi = 10.5301/ejo.5000633 | s2cid = 83593 }}</ref><ref>{{cite journal | vauthors = Yuan F, Li L, Chen X, Yan X, Wang L | title = Biodegradable 3D-Porous Collagen Matrix (Ologen) Compared with Mitomycin C for Treatment of Primary Open-Angle Glaucoma: Results at 5 Years | journal = Journal of Ophthalmology | volume = 2015 | issue = 637537 | pages = 637537 | year = 2015 | pmid = 26078875 | pmc = 4452460 | doi = 10.1155/2015/637537 | doi-access = free }}</ref><ref name="pmid23640614">{{cite journal | vauthors = Tanuj D, Amit S, Saptorshi M, Meenakshi G | title = Combined subconjunctival and subscleral ologen implant insertion in trabeculectomy | journal = Eye | volume = 27 | issue = 7 | pages = 889 | date = July 2013 | pmid = 23640614 | pmc = 3709396 | doi = 10.1038/eye.2013.76 }}</ref><ref>{{cite journal | vauthors = Cillino S, Casuccio A, Di Pace F, Cagini C, Ferraro LL, Cillino G | title = Biodegradable collagen matrix implant versus mitomycin-C in trabeculectomy: five-year follow-up | journal = BMC Ophthalmology | volume = 16 | issue = 24 | pages = 24 | date = March 2016 | pmid = 26946419 | pmc = 4779569 | doi = 10.1186/s12886-016-0198-0 | doi-access = free }}</ref>

Collagen matrix prevents scarring by randomizing and modulating fibroblast proliferation in addition to mechanically preventing wound contraction and adhesion.

====Glaucoma drainage implants====
{{Main|Glaucoma valve}}
The first glaucoma drainage implant was developed in 1966.<ref>{{cite web |url=http://www.glaucoma.org.nz/memberFiles/Eyelights11-05.pdf |title=Eyelights Newsletter: About Glaucoma New Zealand |publisher=Glaucoma.org |access-date=20 February 2014 |url-status=live |archive-url=https://web.archive.org/web/20150113141756/http://glaucoma.org.nz/memberFiles/Eyelights11-05.pdf |archive-date=13 January 2015 }}</ref> Since then, several types of implants have followed on from the original: the Baerveldt tube shunt, or the valved implants, such as the Ahmed glaucoma valve implant or the ExPress Mini Shunt and the later generation pressure ridge Molteno implants. These are indicated for glaucoma patients not responding to maximal medical therapy, with previous failed guarded filtering surgery (trabeculectomy). The flow tube is inserted into the anterior chamber of the eye, and the plate is implanted underneath the conjunctiva to allow a flow of aqueous fluid out of the eye into a chamber called a [[bleb (medicine)|bleb]].

*The first-generation Molteno and other nonvalved implants sometimes require the ligation of the tube until the bleb formed is mildly fibrosed and water-tight.<ref name=VicrylTie>{{cite journal | vauthors = Molteno AC, Polkinghorne PJ, Bowbyes JA | title = The vicryl tie technique for inserting a draining implant in the treatment of secondary glaucoma | journal = Australian and New Zealand Journal of Ophthalmology | volume = 14 | issue = 4 | pages = 343–354 | date = November 1986 | pmid = 3814422 | doi = 10.1111/j.1442-9071.1986.tb00470.x | doi-access = free }}
</ref> This is done to reduce postoperative hypotony—sudden drops in postoperative intraocular pressure.
* Valved implants, such as the Ahmed glaucoma valve, attempt to control postoperative hypotony by using a mechanical valve.
* Ab interno implants, such as the Xen Gel Stent, are transscleral implants by an ab interno procedure to channel aqueous humor into the non-dissected Tenon's space, creating a subconjunctival drainage area similar to a bleb.<ref>{{cite journal | vauthors = Lewis RA | title = Ab interno approach to the subconjunctival space using a collagen glaucoma stent | journal = Journal of Cataract and Refractive Surgery | volume = 40 | issue = 8 | pages = 1301–1306 | date = August 2014 | pmid = 24943904 | doi = 10.1016/j.jcrs.2014.01.032 }}</ref><ref>{{cite web|title=Xen Gel Stent|url=http://www.aquesys.com/xen.aspx|website=AqueSys|access-date=27 June 2015|url-status=dead|archive-url=https://web.archive.org/web/20150629022832/http://aquesys.com/xen.aspx|archive-date=29 June 2015}}</ref> The implants are transscleral and different from other ab interno implants that do not create a transscleral drainage, such as iStent, CyPass, or Hydrus.<ref>{{cite news|title=Advances in Glaucoma Filtration Surgery|url=http://glaucomatoday.com/2014/04/advances-in-glaucoma-filtration-surgery|access-date=27 June 2015|publisher=Glaucoma Today|url-status=live|archive-url=https://web.archive.org/web/20150629194028/http://glaucomatoday.com/2014/04/advances-in-glaucoma-filtration-surgery|archive-date=29 June 2015}}</ref><ref>{{cite journal | vauthors = Otarola F, Virgili G, Shah A, Hu K, Bunce C, Gazzard G | title = Ab interno trabecular bypass surgery with Schlemm´s canal microstent (Hydrus) for open angle glaucoma | journal = The Cochrane Database of Systematic Reviews | volume = 2020 | issue = 3 | pages = CD012740 | date = March 2020 | pmid = 32147807 | pmc = 7061024 | doi = 10.1002/14651858.cd012740.pub2 }}</ref>

The ongoing scarring over the conjunctival dissipation segment of the shunt may become too thick for the aqueous humor to filter through. This may require preventive measures using antifibrotic medications, such as 5-fluorouracil or mitomycin-C (during the procedure), or other nonantifibrotic medication methods, such as collagen matrix implant,<ref>{{cite journal | vauthors = Rosentreter A, Schild AM, Dinslage S, Dietlein TS | title = Biodegradable implant for tissue repair after glaucoma drainage device surgery | journal = Journal of Glaucoma | volume = 21 | issue = 2 | pages = 76–78 | date = February 2012 | pmid = 21278584 | doi = 10.1097/IJG.0b013e3182027ab0 | s2cid = 40206358 }}</ref><ref name="Capsule excision and Ologen implant">{{cite journal | vauthors = Rosentreter A, Mellein AC, Konen WW, Dietlein TS | title = Capsule excision and Ologen implantation for revision after glaucoma drainage device surgery | journal = Graefe's Archive for Clinical and Experimental Ophthalmology = Albrecht von Graefes Archiv für Klinische und Experimentelle Ophthalmologie | volume = 248 | issue = 9 | pages = 1319–1324 | date = September 2010 | pmid = 20405139 | doi = 10.1007/s00417-010-1385-y | s2cid = 10384646 }}</ref> or biodegradable spacer, or later on create a necessity for revision surgery with the sole or combinative use of donor patch grafts or collagen matrix implant.<ref name="Capsule excision and Ologen implant"/>

====Laser-assisted nonpenetrating deep sclerectomy====
The most common surgical approach currently used for the treatment of glaucoma is trabeculectomy, in which the sclera is punctured to alleviate intraocular pressure.

Nonpenetrating deep sclerectomy (NPDS) surgery is a similar, but modified, procedure, in which instead of puncturing the scleral bed and trabecular meshwork under a scleral flap, a second deep scleral flap is created, excised, with further procedures of deroofing the Schlemm's canal, upon which, percolation of liquid from the inner eye is achieved and thus alleviating intraocular pressure, without penetrating the eye. NPDS is demonstrated to have significantly fewer side effects than trabeculectomy.<ref>{{cite journal | vauthors = Chiselita D | title = Non-penetrating deep sclerectomy versus trabeculectomy in primary open-angle glaucoma surgery | journal = Eye | volume = 15 | issue = Pt 2 | pages = 197–201 | date = April 2001 | pmid = 11339590 | doi = 10.1038/eye.2001.60 | doi-access = free }}</ref> However, NPDS is performed manually and requires higher level of skills that may be assisted with instruments<!-- to achieve a lengthy learning curve-->.{{Citation needed|date=May 2009}}   In order to prevent wound adhesion after deep scleral excision and to maintain good filtering results, NPDS as with other non-penetrating procedures is sometimes performed with a variety of biocompatible spacers or devices, such as the Aquaflow collagen wick,<ref>{{cite journal |url=https://www.reviewofophthalmology.com/article/making-the-case-for-nonpenetrating-surgery |title=Making the Case for Nonpenetrating Surgery|journal=Review of Ophthalmology| vauthors = Ahmed IK |volume=12|issue=9|date=1 September 2005}}</ref> ologen Collagen Matrix,<ref name="pmid23640614" /><ref>{{cite journal | vauthors = Aptel F, Dumas S, Denis P | title = Ultrasound biomicroscopy and optical coherence tomography imaging of filtering blebs after deep sclerectomy with new collagen implant | journal = European Journal of Ophthalmology | volume = 19 | issue = 2 | pages = 223–230 | year = 2009 | pmid = 19253238 | doi = 10.1177/112067210901900208 | s2cid = 22594085 }}</ref><ref>{{cite conference | vauthors = Matthew SJ, Sarkisian S, Nathan B, James MR  |title=Initial experience using a collagen matrix implant (ologen) as a wound modulator with canaloplasty: 12 month results |url=http://www.abstractsonline.com/Plan/ViewAbstract.aspx?mID=2866&sKey=aa4eef9a-b55d-43a5-a9f7-c71c79616c08&cKey=7035e4dc-493a-4f51-adae-eedc3adbe114&mKey=%7BF0FCE029-9BF8-4E7C-B48E-9FF7711D4A0E%7D |date=May 2012 |conference=ARVO |location=Ft. Lauderdale }}</ref> or Xenoplast glaucoma implant.<ref>{{cite web |vauthors=Anisimova SY, Anisimova SI, Larionov EV |title=Biological drainage – Xenoplast in glaucoma surgery (experimental and 10-year of clinical follow-up) |url=http://www.oic.it/~egscopenaghen2012/posters/june18/P2.24/poster.pdf |date=2012 |publisher=EGS Congress |location=Copenhagen |url-status=live |archive-url=https://web.archive.org/web/20131017051726/http://www.oic.it/~egscopenaghen2012/posters/june18/P2.24/poster.pdf |archive-date=17 October 2013 }}</ref>

Laser-assisted NPDS is performed with the use of a CO<sub>2</sub> laser system. The laser-based system is self-terminating once the required scleral thickness and adequate drainage of the intraocular fluid have been achieved. This self-regulation effect is achieved as the CO<sub>2</sub> laser essentially stops ablating as soon as it comes in contact with the intraocular percolated liquid, which occurs as soon as the laser reaches the optimal residual intact layer thickness.

==== Clear lens extraction ====
{{main|Clear lens extraction}}
For people with chronic closed-angle glaucoma, lens extraction can relieve the block created by the pupil and help regulate the intraocular pressure.<ref>{{cite journal | vauthors = Ong AY, Ng SM, Vedula SS, Friedman DS | title = Lens extraction for chronic angle-closure glaucoma | journal = The Cochrane Database of Systematic Reviews | volume = 2021 | issue = 3 | pages = CD005555 | date = March 2021 | pmid = 33759192 | pmc = 8094223 | doi = 10.1002/14651858.CD005555.pub3 }}</ref> A study found that CLE is even more effective than laser peripheral [[iridotomy]] in patients with angle closure glaucoma.<ref>{{Cite journal |last1=Tanner |first1=Luke |last2=Gazzard |first2=Gus |last3=Nolan |first3=Winifred P. |last4=Foster |first4=Paul J. |date=January 2020 |title=Has the EAGLE landed for the use of clear lens extraction in angle-closure glaucoma? And how should primary angle-closure suspects be treated? |journal=Eye |language=en |volume=34 |issue=1 |pages=40–50 |doi=10.1038/s41433-019-0634-5 |pmid=31649349 |issn=1476-5454|pmc=7002615 }}</ref> A systematic review comparing lens extraction and laser peripheral [[Iridectomy|iridotomy]] for treating acute primary angle closure found that lens extraction potentially provides better [[intraocular pressure]] control and reduces medication needs over time. However, it remains uncertain if it significantly lowers the risk of [[Relapse|recurrent episodes]] or reduces the need for additional [[Surgery|operations]].<ref>{{Cite journal |last1=Ong |first1=Ariel Yuhan |last2=McCann |first2=Paul |last3=Perera |first3=Shamira A |last4=Lim |first4=Fiona |last5=Ng |first5=Sueko M |last6=Friedman |first6=David S |last7=Chang |first7=Dolly |date=2023-03-08 |editor-last=Cochrane Eyes and Vision Group |title=Lens extraction versus laser peripheral iridotomy for acute primary angle closure |journal=Cochrane Database of Systematic Reviews |language=en |volume=2023 |issue=3 |pages=CD015116 |doi=10.1002/14651858.CD015116.pub2 |pmc=9994579 |pmid=36884304}}</ref> 

=== Treatment approaches for primary glaucoma ===
'''Primary angle closure glaucoma:''' Once any symptoms have been controlled, the first line (and often definitive) treatment is laser [[iridotomy]]. This may be performed using either Nd:YAG or argon lasers, or in some cases by conventional incisional surgery. The goal of treatment is to reverse and prevent contact between the iris and trabecular meshwork. In early to moderately advanced cases, iridotomy is successful in opening the angle in around 75% of cases. In the other 25%, laser iridoplasty, medication (pilocarpine) or incisional surgery may be required.

'''Primary open-angle glaucoma:''' Prostaglandin agonists work by opening uveoscleral passageways. Beta-blockers, such as timolol, work by decreasing aqueous formation. [[Carbonic anhydrase inhibitor]]s decrease bicarbonate formation from ciliary processes in the eye, thus decreasing the formation of aqueous humor. Parasympathetic analogs are drugs that work on the trabecular outflow by opening up the passageway and constricting the pupil. Alpha 2 agonists ([[brimonidine]], [[apraclonidine]]) both decrease fluid production (via inhibition of AC) and increase drainage. A review of people with primary open-angle glaucoma and ocular hypertension concluded that medical IOP-lowering treatment slowed down the progression of visual field loss.<ref name="Vass2007" />

=== Neovascular glaucoma ===
[[anti–vascular endothelial growth factor therapy|Anti-VEGF agents]] as injectable medications, along with other standard of care treatment for decreasing intraocular pressure, may improve pressure in people with neovascular glaucoma for short periods of time.<ref name=":0">{{Cite journal |last1=Rittiphairoj |first1=Thanitsara |last2=Roberti |first2=Gloria |last3=Michelessi |first3=Manuele |date=2023-04-03 |title=Anti-vascular endothelial growth factor for neovascular glaucoma |url= |journal=The Cochrane Database of Systematic Reviews |volume=4 |issue=4 |pages=CD007920 |doi=10.1002/14651858.CD007920.pub4 |issn=1469-493X |pmc=10069372 |pmid=37010901 }}</ref> Evidence suggests that this improvement may last 4–6 weeks.<ref name=":0" /> There is no sufficient evidence to suggest that anti-VEGF medications are effective either for short-term or for longer-term treatment.<ref name=":0" /> The short, medium, and long-term safety of anti-VEGF treatment has not been well investigated.<ref name=":0" />

=== Other ===
*[[Cannabis]] is not suggested for treatment of glaucoma by the [[American Glaucoma Society]] for adults or for children.<ref>{{Cite journal |last1=Grossman |first1=Adriana L. |last2=Javitt |first2=Matthew J. |last3=Moster |first3=Steven J. |last4=Grajewski |first4=Alana L. |last5=Beck |first5=Allen D. |last6=Blieden |first6=Lauren S. |last7=Bitrian |first7=Elena |last8=Chang |first8=Ta C. |last9=Freedman |first9=Sharon F. |last10=Hodapp |first10=Elizabeth |last11=Joos |first11=Keren M. |last12=Reiser |first12=Bibiana J. |last13=Tanna |first13=Angelo P. |date=2019-11-01 |title=American Glaucoma Society Position Statement on Cannabinoid Use in Pediatric Glaucoma Patients |url=https://www.sciencedirect.com/science/article/pii/S2589419619302492 |journal=Ophthalmology Glaucoma |language=en |volume=2 |issue=6 |pages=365–366 |doi=10.1016/j.ogla.2019.07.007 |pmid=32672568 |s2cid=214292703 |issn=2589-4196|url-access=subscription }}</ref><ref>{{cite journal |vauthors=Jampel H |date=February 2010 |title=American glaucoma society position statement: marijuana and the treatment of glaucoma |journal=Journal of Glaucoma |volume=19 |issue=2 |pages=75–76 |doi=10.1097/ijg.0b013e3181d12e39 |pmid=20160576}}</ref>
*[[Sepetaprost]], investigational new drug

==Prognosis==
In open-angle glaucoma, the typical progression from normal vision to complete blindness takes about 25 years to 70 years without treatment, depending on the method of estimation used.<ref name=Heijl>{{cite journal | vauthors = Heijl A, Bengtsson B, Hyman L, Leske MC | title = Natural history of open-angle glaucoma | journal = Ophthalmology | volume = 116 | issue = 12 | pages = 2271–2276 | date = December 2009 | pmid = 19854514 | doi = 10.1016/j.ophtha.2009.06.042 | url = https://lup.lub.lu.se/record/1500002 | type = Submitted manuscript }}</ref>

== History ==
The association of elevated intraocular pressure (IOP) and glaucoma was first described by Englishman [[Richard Banister]] in 1622: "...that the Eye be grown more solid and hard, then naturally it should be...".<ref>{{cite book | vauthors = Bannister R | title = Treatise of One Hundred and Thirteen Diseases of the Eyes and Eyelids. | location = London | date = 1622 }}</ref> Angle-closure glaucoma was treated with cataract extraction by John Collins Warren in Boston as early as 1806.<ref name="Ophthalmology and Eye Diseases">{{cite journal | vauthors = Leffler CT, Schwartz SG, Wainsztein RD, Pflugrath A, Peterson E | title = Ophthalmology in North America: Early Stories (1491-1801) | journal = Ophthalmology and Eye Diseases | volume = 9 | pages = 1179172117721902 | year = 2017 | pmid = 28804247 | pmc = 5533269 | doi = 10.1177/1179172117721902 }}</ref> The invention of the ophthalmoscope by [[Hermann Helmholtz]] in 1851 enabled ophthalmologists for the first time to identify the pathological hallmark of glaucoma, the excavation of the optic nerve head due to retinal ganglion cell loss. The first reliable instrument to measure intraocular pressure was invented by Norwegian ophthalmologist [[Hjalmar August Schiøtz]] in 1905. About half a century later, [[Hans Goldmann]] in Bern, Switzerland, developed his applanation tonometer which still today - despite numerous new innovations in diagnostics - is considered the gold standard of determining this crucial pathogenic factor. In the late 20th century, further pathomechanisms beyond elevated IOP were discovered and became the subject of research like insufficient blood supply – often associated with low or irregular blood pressure – to the retina and optic nerve head.<ref>{{cite book | vauthors = Albert D, Edwards D | title = The History of Ophthalmology |publisher=Wiley | location = Cambridge, Mass. | date = 1996 }}</ref> The first drug to reduce IOP, [[pilocarpine]], was introduced in the 1870s; other major innovations in pharmacological glaucoma therapy were the introduction of [[beta blocker]] eye drops in the 1970s and of [[prostaglandin analogue]]s and topical (locally administered) [[carbonic anhydrase inhibitor]]s in the mid-1990s. Early surgical techniques like iridectomy and fistulating methods have recently been supplemented by less invasive procedures like small implants, a range of options now widely called MIGS (micro-invasive glaucoma surgery).

===Etymology===
The word "glaucoma" comes from the [[Ancient Greek]] {{lang|grc|γλαύκωμα}},<ref>{{OEtymD|glaucoma}}</ref> a derivative of {{lang|grc|γλαυκός}} ''(glaukos),''<ref>{{LSJ|glauko/s1|γλαυκός|ref}}.</ref> which commonly described the color of eyes which were not dark (i.e. blue, green, light gray). Eyes described as {{lang|grc|γλαυκός}} due to disease might have had a gray cataract in the Hippocratic era, or, in the early Common Era, the greenish pupillary hue sometimes seen in angle-closure glaucoma.<ref name="Lef2015">{{cite journal | vauthors = Leffler CT, Schwartz SG, Giliberti FM, Young MT, Bermudez D | title = What was Glaucoma Called Before the 20th Century? | journal = Ophthalmology and Eye Diseases | volume = 7 | pages = 21–33 | date = 2015 | pmid = 26483611 | pmc = 4601337 | doi = 10.4137/OED.S32004 | url = http://www.la-press.com/what-was-glaucoma-called-before-the-20th-century-article-a5118-abstract?article_id=5118 | url-status = live | archive-url = https://web.archive.org/web/20160423184924/http://www.la-press.com/what-was-glaucoma-called-before-the-20th-century-article-a5118-abstract?article_id=5118 | archive-date = 23 April 2016 }}</ref><ref name="Clinical Ophthalmology">{{cite journal | vauthors = Leffler CT, Schwartz SG, Hadi TM, Salman A, Vasuki V | title = The early history of glaucoma: the glaucous eye (800 BC to 1050 AD) | journal = Clinical Ophthalmology | volume = 9 | pages = 207–215 | year = 2015 | pmid = 25673972 | pmc = 4321651 | doi = 10.2147/OPTH.S77471 | doi-access = free }}</ref> This colour is reflected in the Chinese word for glaucoma, 青光眼 ''(qīngguāngyǎn),'' literally “[[cyan]]-light eye”. An alternative hypothesis connects the name to the Ancient Greek noun for 'owl',<ref>{{Cite journal |last1=Tsatsos |first1=Michael |last2=Broadway |first2=David |date=November 2007 |title=Controversies in the history of glaucoma: is it all a load of old Greek? |journal=The British Journal of Ophthalmology |volume=91 |issue=11 |pages=1561–1562 |doi=10.1136/bjo.2007.114298 |issn=0007-1161 |pmc=2095442 |pmid=17947272}}</ref> {{lang|grc|γλαύξ}} or {{lang|grc|γλαῦξ}} (both ''glaux'').

==Research==
[[File:Exploring-Eye-Movements-in-Patients-with-Glaucoma-When-Viewing-a-Driving-Scene-pone.0009710.s001.ogv|thumb|right|Scientists track eye movements in glaucoma patients to check vision impairment while driving.]]

=== Eye drops vs. other treatments ===
The TAGS randomised controlled trial investigated if eye drops or trabeculectomy is more effective in treating advanced primary open-angle glaucoma. After two years researchers found that vision and quality of life are similar in both treatments. At the same time eye pressure was lower in people who underwent surgery and in the long-run surgery is more cost-effective.<ref>{{Cite journal |date=2022-03-31 |title=Advanced glaucoma: surgery lowers pressure in the eye more effectively than eye drops |url=https://evidence.nihr.ac.uk/alert/advanced-glaucoma-surgery-is-effective/ |journal=NIHR Evidence |type=Plain English summary |language=en |publisher=National Institute for Health and Care Research |doi=10.3310/alert_49606|s2cid=247918434 |url-access=subscription }}</ref><ref>{{cite journal | vauthors = King AJ, Fernie G, Hudson J, Kernohan A, Azuara-Blanco A, Burr J, Homer T, Shabaninejad H, Sparrow JM, Garway-Heath D, Barton K, Norrie J, McDonald A, Vale L, MacLennan G | display-authors = 6 | title = Primary trabeculectomy versus primary glaucoma eye drops for newly diagnosed advanced glaucoma: TAGS RCT | journal = Health Technology Assessment | volume = 25 | issue = 72 | pages = 1–158 | date = November 2021 | pmid = 34854808 | doi = 10.3310/hta25720 | doi-access = free | hdl = 2164/18078 | hdl-access = free }}</ref>

The LiGHT trial compared the effectiveness of eye drops and selective laser trabeculoplasty for open angle glaucoma. Both 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.<ref name="Gazzard_2019">{{cite journal | vauthors = Gazzard G, Konstantakopoulou E, Garway-Heath D, Garg A, Vickerstaff V, Hunter R, Ambler G, Bunce C, Wormald R, Nathwani N, Barton K, Rubin G, Buszewicz M | display-authors = 6 | title = Selective laser trabeculoplasty versus eye drops for first-line treatment of ocular hypertension and glaucoma (LiGHT): a multicentre randomised controlled trial | journal = Lancet | volume = 393 | issue = 10180 | pages = 1505–1516 | date = April 2019 | pmid = 30862377 | pmc = 6495367 | doi = 10.1016/S0140-6736(18)32213-X }}; {{lay source |template=cite web |date= 4 June 2019 |title=A laser eye procedure can be effective and safe if used early as treatment for glaucoma |url=https://evidence.nihr.ac.uk/alert/a-laser-eye-procedure-can-be-effective-and-safe-if-used-early-as-treatment-for-glaucoma | work =NIHR Evidence |quote = Plain English summary |publisher=National Institute for Health and Care Research |doi=10.3310/signal-000774 }}</ref>

===Comparison of effects of brimonidine and timolol===
A 2013 [[Cochrane Collaboration|Cochrane systematic review]] compared the effect of brimonidine and timolol in slowing the progression of open angle glaucoma in adult participants.<ref name="Sena">{{cite journal | vauthors = Sena DF, Lindsley K | title = Neuroprotection for treatment of glaucoma in adults | journal = The Cochrane Database of Systematic Reviews | volume = 1 | pages = CD006539 | date = January 2017 | issue = 1 | pmid = 28122126 | pmc = 5370094 | doi = 10.1002/14651858.CD006539.pub4 }}</ref> The results showed that participants assigned to brimonidine showed less visual field progression than those assigned to timolol, though the results were not significant, given the heavy [[Lost to follow-up|loss-to-followup]] and limited evidence.<ref name=Sena/> The mean intraocular pressures for both groups were similar. Participants in the brimonidine group had a higher occurrence of side effects caused by medication than participants in the timolol group.<ref name=Sena/>

==Social disparities in glaucoma care and research==

A study conducted in UK showed that people living in an area of high deprivation were likely to be diagnosed in the later stage of the disease.<ref>{{cite journal | vauthors = Day F, Buchan JC, Cassells-Brown A, Fear J, Dixon R, Wood F | title = A glaucoma equity profile: correlating disease distribution with service provision and uptake in a population in Northern England, UK | journal = Eye | volume = 24 | issue = 9 | pages = 1478–1485 | date = September 2010 | pmid = 20508654 | doi = 10.1038/eye.2010.73 | s2cid = 23130257 | doi-access = free }}</ref> It also showed that there were lack of professional ophthalmic services in the area of high deprivation.

A study in 2017 shows that there is a huge difference in the volume of glaucoma testing depending on the type of insurance in the US.<ref>{{cite journal | vauthors = Elam AR, Andrews C, Musch DC, Lee PP, Stein JD | title = Large Disparities in Receipt of Glaucoma Care between Enrollees in Medicaid and Those with Commercial Health Insurance | journal = Ophthalmology | volume = 124 | issue = 10 | pages = 1442–1448 | date = October 2017 | pmid = 28583710 | pmc = 6145133 | doi = 10.1016/j.ophtha.2017.05.003 }}</ref> Researchers reviewed 21,766 persons age ≥ 40 years old with newly diagnosed open-angle glaucoma (OAG) and found that Medicaid recipients had substantially lower volume of glaucoma testing performed compared to patients with commercial health insurance.

Results from a meta-analysis of 33,428 primary open-angle glaucoma (POAG) participants published in 2021 suggest that there are substantial ethnic and racial disparities in clinical trials in the US.<ref>{{cite journal | vauthors = Allison K, Patel DG, Greene L | title = Racial and Ethnic Disparities in Primary Open-Angle Glaucoma Clinical Trials: A Systematic Review and Meta-analysis | journal = JAMA Network Open | volume = 4 | issue = 5 | pages = e218348 | date = May 2021 | pmid = 34003274 | pmc = 8132140 | doi = 10.1001/jamanetworkopen.2021.8348 }}</ref> Although ethnic and racial minorities have a higher disease burden, the 70.7% of the study participants was White as opposed to 16.8% Black and 3.4% Hispanic/Latino.

==See also==

* [[Jay Horwitz]] (born 1945), New York Mets executive born with glaucoma

== References ==
{{Reflist}}

== External links ==
{{Portal|Medicine}}
* [https://www.sciencedirect.com/science/article/pii/S2667376222000130 Role of ocular blood flow in normal tension glaucoma], Advances in Ophthalmology Practice and Research, Volume 2, Issue 1, May–June 2022.
* [https://www.ncbi.nlm.nih.gov/books/NBK1135/  GeneReview/NCBI/NIH/UW entry on Primary Congenital Glaucoma]

{{Medical condition classification and resources
| DiseasesDB     = 5226
| ICD11          = {{ICD11|9C61}}
| ICD10          = {{ICD10|H40}}, {{ICD10|H42}}
| ICD9           = {{ICD9|365}}
| ICDO           =
| OMIM           =
| MedlinePlus    = 001620
| eMedicineSubj  = oph
| eMedicineTopic = 578
| MeshID         = D005901
}}
{{Eye pathology}}
{{Authority control}}

[[Category:Glaucoma| ]]
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[[Category:Blindness]]
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