Last Updated: August 16, 2022

Glaucoma is a group of eye conditions, the common feature of which is characteristic damage of the optic nerve which transmits light signals to the brain. Left untreated, glaucoma can cause irreversible vision loss. Currently, the only established modifiable risk factor for glaucoma is elevated pressure inside the eye.

Glaucoma falls under theEyes & VisionandHealthy Aging & Longevitycategories.

What is glaucoma?

Glaucoma is a group of eye conditions (typically classified as open- or closed-angle, and primary or secondary) characterized by progressive damage to the optic nerve head. Because the optic nerve transmits visual information from the eye to the brain, glaucoma can lead to vision problems if not treated early, and can eventually cause irreversible vision loss if left untreated.[1]

What are the main signs and symptoms of glaucoma?

Open-angle glaucoma is usually asymptomatic in the early stages, with visual symptoms developing subtly and gradually over time. The most common visual symptoms reported are needing more light, blurry vision, seeing glare, and difficulty seeing objects in peripheral vision.[2]

Angle-closure glaucoma can present chronically, often without symptoms. However, it can also present acutely, with a sudden increase in the pressure inside the eye causing symptoms that include blurry vision, reddening of the eye, intense eye pain, severe headache, and nausea and vomiting.[3]

How is glaucoma diagnosed?

A complete eye exam for glaucoma diagnosis typically includes five tests:[4]

  • Tonometry; to measure intraocular pressure
  • Pachymetry; to measure the thickness of the cornea
  • Ophthalmoscopy; to examine the optic nerve for damage
  • Perimetry; to assess the field of vision
  • Gonioscopy; to measure the eye’s anterior chamber angle
What are some of the main medical treatments for glaucoma?

Elevated intraocular pressure (pressure inside the eye) is so far the only treatable risk factor for glaucoma. As such, current management strategies all aim to lower intraocular pressure. Depending on the situation, this is achieved with medications (applied topically to the eye or taken orally), laser treatment, surgery, or a combination of any of these.[5]

Have any supplements been studied for glaucoma?

Limited preliminary evidence suggests that a handful of supplements may have beneficial effects in glaucoma by reducing intraocular pressure, improving inner retinal function, increasing blood flow, or slowing visual field loss. These supplements include ginkgo biloba, blackcurrant anthocyanins, epigallocatechin-gallate, vitamin B3, and Erigeron breviscapus (a Chinese herb).[6][7]

How could diet affect glaucoma?

The available evidence examining the links between dietary patterns or dietary components and glaucoma risk is limited, mostly observational, and often conflicting. That said, the consumption of fruits and vegetables rich in vitamin A, carotenes, and nitrate has been linked to a reduced risk of glaucoma. Moreover, some studies have linked caffeinated tea intake with a lower risk of glaucoma. On the other hand, caffeine and caffeinated coffee transiently increase intraocular pressure (a risk factor for glaucoma onset and progression) in individuals with glaucoma, but do not seem to affect individuals without glaucoma.[8]

Are there any other treatments for glaucoma?

A small number of studies have examined the potential efficacy of non-medical glaucoma treatments, including exercise, cannabis, acupuncture, and relaxation techniques.

The effects of exercise on intraocular pressure have been mixed, and seem to depend on the type and intensity of exercise. While marijuana use has been shown to effectively reduce intraocular pressure, its effects are short-lived, requiring dosing of 8–10 times per day for a sustained therapeutic effect. Clear evidence supporting the efficacy of acupuncture and relaxation techniques is lacking.[9][10][11][12]

What causes glaucoma?

Although the exact causes of primary glaucoma have not yet been established, in most cases, the level of intraocular pressure is related to the degree of glaucomatous damage observed. Independently or in addition to intraocular pressure, other factors — including an insufficient supply of oxygen to the optic nerve head, excessive stimulation of the glutamate system, and the formation of free radicals and inflammatory cytokines — may individually or collectively contribute to the development of glaucomatous damage.[13][14]

Examine Database: Glaucoma
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  1. ^Robert N Weinreb, Tin Aung, Felipe A MedeirosThe pathophysiology and treatment of glaucoma: a reviewJAMA.(2014 May 14)
  2. ^Cindy X Hu, Camila Zangalli, Michael Hsieh, Lalita Gupta, Alice L Williams, Jesse Richman, George L SpaethWhat do patients with glaucoma see? Visual symptoms reported by patients with glaucomaAm J Med Sci.(2014 Nov)
  3. ^Blanca C Flores-Sánchez, Andrew J TathamAcute angle closure glaucomaBr J Hosp Med (Lond).(2019 Dec 2)
  4. ^Ravi Thomas, Klaus Loibl, R ParikhEvaluation of a glaucoma patientIndian J Ophthalmol.(2011 Jan)
  5. ^Joshua D Stein, Anthony P Khawaja, Jennifer S WeizerGlaucoma in Adults-Screening, Diagnosis, and Management: A ReviewJAMA.(2021 Jan 12)
  6. ^Foroogh Fahmideh, Nicoletta Marchesi, Annalisa Barbieri, Stefano Govoni, Alessia PascaleNon-drug interventions in glaucoma: Putative roles for lifestyle, diet and nutritional supplementsSurv Ophthalmol.(2021 Sep 23)
  7. ^James R Tribble, Flora Hui, Melissa Jöe, Katharina Bell, Vicki Chrysostomou, Jonathan G Crowston, Pete A WilliamsTargeting Diet and Exercise for Neuroprotection and Neurorecovery in GlaucomaCells.(2021 Feb 1)
  8. ^Adi M Al Owaifeer, Abdulaziz A Al TaisanThe Role of Diet in Glaucoma: A Review of the Current EvidenceOphthalmol Ther.(2018 Jun)
  9. ^Ming Ming Zhu, Jimmy Shiu Ming Lai, Bonnie Nga Kwan Choy, Jennifer Wei Huen Shum, Amy Cheuk Yin Lo, Alex Lap Ki Ng, Jonathan Cheuk Hung Chan, Kwok Fai SoPhysical exercise and glaucoma: a review on the roles of physical exercise on intraocular pressure control, ocular blood flow regulation, neuroprotection and glaucoma-related mental healthActa Ophthalmol.(2018 Sep)
  10. ^K GreenMarijuana smoking vs cannabinoids for glaucoma therapyArch Ophthalmol.(1998 Nov)
  11. ^Simon K Law, Lin Wang, Tianjing LiAcupuncture for glaucomaCochrane Database Syst Rev.(2020 Feb 7)
  12. ^G Kaluza, I Strempel, H MaurerStress reactivity of intraocular pressure after relaxation training in open-angle glaucoma patientsJ Behav Med.(1996 Dec)
  13. ^Josef Flammer, Selim Orgül, Vital P Costa, Nicola Orzalesi, Günter K Krieglstein, Luis Metzner Serra, Jean-Paul Renard, Einar StefánssonThe impact of ocular blood flow in glaucomaProg Retin Eye Res.(2002 Jul)
  14. ^Shoeb Ahmad S, Abdul Ghani S, Hemalata Rajagopal TCurrent Concepts in the Biochemical Mechanisms of Glaucomatous Neurodegeneration.J Curr Glaucoma Pract.(2013)
  15. ^Mantravadi AV, Vadhar NGlaucoma.Prim Care.(2015-Sep)
  16. ^Rozpędek-Kamińska W, Wojtczak R, Szaflik JP, Szaflik J, Majsterek IThe Genetic and Endoplasmic Reticulum-Mediated Molecular Mechanisms of Primary Open-Angle Glaucoma.Int J Mol Sci.(2020-Jun-11)
  17. ^Anthea Worley, Karen Grimmer-SomersRisk factors for glaucoma: what do they really mean?Aust J Prim Health.(2011)
  18. ^Goel M, Picciani RG, Lee RK, Bhattacharya SKAqueous humor dynamics: a review.Open Ophthalmol J.(2010-Sep-03)
  19. ^Killer HE, Pircher ANormal tension glaucoma: review of current understanding and mechanisms of the pathogenesis.Eye (Lond).(2018-05)
  20. ^Chen Y, Hughes G, Chen X, Qian S, Cao W, Wang L, Wang M, Sun XGenetic Variants Associated With Different Risks for High Tension Glaucoma and Normal Tension Glaucoma in a Chinese Population.Invest Ophthalmol Vis Sci.(2015-Apr)
Examine Database References
  1. Heart Rate - Merritt JC, Crawford WJ, Alexander PC, Anduze AL, Gelbart SSEffect of marihuana on intraocular and blood pressure in glaucomaOphthalmology.(1980 Mar)
  2. Intraocular Pressure - Terai N, Gedenk A, Spoerl E, Pillunat LE, Stodtmeister RThe short-term effect of flavonoid-rich dark chocolate on retinal vessel diameter in glaucoma patients and age-matched controlsActa Ophthalmol.(2014 Aug)
  3. Intraocular Pressure - Parisi V, Coppola G, Centofanti M, Oddone F, Angrisani AM, Ziccardi L, Ricci B, Quaranta L, Manni GEvidence of the neuroprotective role of citicoline in glaucoma patientsProg Brain Res.(2008)
  4. Ocular Blood Flow - Park JW, Kwon HJ, Chung WS, Kim CY, Seong GJShort-term effects of Ginkgo biloba extract on peripapillary retinal blood flow in normal tension glaucomaKorean J Ophthalmol.(2011 Oct)