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Can supplements lower eye pressure?

Not reliably. Fish oil capsules lowered eye pressure slightly in 105 adults whose pressure was already normal (grade C), and black currant extract lowered it in two small studies. A 2026 review of supplement studies in glaucoma found no clear change in pressure after 6 months. Prescription eye drops lower pressure in 114 trials (grade A) and reduce the chance of glaucoma damage. Caffeine can raise eye pressure for about an hour.

Last reviewed

How we grade evidenceEditorial policy

What the studies found

  • Grade A. Prescription eye drops reliably lower eye pressure. In a network meta-analysis of 114 trials, every first-line drop worked better than placebo at 3 months. In people with raised pressure, a Cochrane review pooled 10 trials and found treatment made new visual field loss, the first sign of glaucoma damage, less likely. (Li 2016; Vass 2007)
  • Grade C. Fish oil lowered pressure a little in people without high pressure. In two pooled placebo-controlled trials, 105 adults took omega-3 capsules or olive oil for 3 months. Pressure dipped to 13.6 mmHg from 14.3 on omega-3 and edged up on placebo. (Downie 2018)
  • Grade C. Plant extracts have only small studies. Black currant anthocyanins lowered pressure in 12 healthy people over 4 weeks and in 21 glaucoma patients over 24 months, against placebo. (Ohguro 2013)
  • Grade C. Across supplement studies in glaucoma, pooled before-and-after results showed no clear change in pressure after 6 months. Nicotinamide (vitamin B3) and ginkgo trials measured retina and visual field, not pressure: nicotinamide improved retinal function short term in 57 people, ginkgo did not change visual fields in 35, and a 2026 review called the nicotinamide evidence insufficient. (Giammanco 2026; Hui 2020; Guo 2014; Giudiceandrea 2026)

Who should be careful

  • Don't swap or skip prescribed drops for supplements; raised pressure usually causes no symptoms until damage is done.
  • Caffeine above 100 mg raised eye pressure from 30 minutes to 1.5 hours afterward in a review of 16 studies, including people with glaucoma. Count coffee, energy drinks and caffeine pills. (Simanjuntak 2026)
  • People on blood thinners (anticoagulants) who take ginkgo or bilberry have a reported bleeding risk. Ask first, and stop nonessential supplements 2 weeks before eye surgery. (Hatfield 2022)
  • Go to urgent care the same day for a painful red eye, sudden blurred or lost vision, rainbow halos around lights, or eye pain with headache and vomiting.
  • If you are pregnant, breastfeeding or under 18, ask a clinician first.

Try first

  • Keep the eye exams and pressure checks your eye doctor sets, and use the drops as prescribed. (Vass 2007)
  • Ask about laser. In a trial of 718 people with raised pressure or early glaucoma, 74% of those who had a quick in-clinic laser treatment (selective laser trabeculoplasty) needed no drops 3 years later. (Gazzard 2019)

Sources

  1. Li T, et al. Comparative Effectiveness of First-Line Medications for Primary Open-Angle Glaucoma: A Systematic Review and Network Meta-analysis. Ophthalmology. 2016. PubMed 26526633 · doi:10.1016/j.ophtha.2015.09.005
  2. Vass C, et al. Medical interventions for primary open angle glaucoma and ocular hypertension. Cochrane Database Syst Rev. 2007. PubMed 17943780 · doi:10.1002/14651858.CD003167.pub3
  3. Downie LE, et al. Oral Omega-3 Supplementation Lowers Intraocular Pressure in Normotensive Adults. Transl Vis Sci Technol. 2018. PubMed 29736322 · doi:10.1167/tvst.7.3.1
  4. Ohguro H, et al. Effects of black currant anthocyanins on intraocular pressure in healthy volunteers and patients with glaucoma. J Ocul Pharmacol Ther. 2013. PubMed 23046438 · doi:10.1089/jop.2012.0071
  5. Giammanco MM, et al. The impact of nutrition on glaucoma progression: evidence from systematic literature review and meta-analysis. Int Ophthalmol. 2026. PubMed 42986498 · doi:10.1007/s10792-026-04328-9
  6. Hui F, et al. Improvement in inner retinal function in glaucoma with nicotinamide (vitamin B3) supplementation: A crossover randomized clinical trial. Clin Exp Ophthalmol. 2020. PubMed 32721104 · doi:10.1111/ceo.13818
  7. Guo X, et al. Effect of Ginkgo biloba on visual field and contrast sensitivity in Chinese patients with normal tension glaucoma: a randomized, crossover clinical trial. Invest Ophthalmol Vis Sci. 2014. PubMed 24282229 · doi:10.1167/iovs.13-13168
  8. Giudiceandrea A, et al. Nicotinamide Supplementation in Glaucoma: A Systematic Review of Human Studies. Nutrients. 2026. PubMed 42739057 · doi:10.3390/nu18172885
  9. Simanjuntak OP, et al. Caffeine Intake Effects on Intraocular Pressure in Healthy and Glaucomatous Populations: A Systematic Review and Meta-Analysis. J Curr Ophthalmol. 2026. PubMed 42666870 · doi:10.4103/joco.joco_43_26
  10. Hatfield J, et al. Dietary supplements and bleeding. Proc (Bayl Univ Med Cent). 2022. PubMed 36304597 · doi:10.1080/08998280.2022.2121575
  11. Gazzard G, et al. Selective laser trabeculoplasty versus eye drops for first-line treatment of ocular hypertension and glaucoma (LiGHT): a multicentre randomised controlled trial. Lancet. 2019. PubMed 30862377 · doi:10.1016/S0140-6736(18)32213-X