Glaucoma is a group of related diseases that cause damage to the eye’s optic nerve and result in visual impairment or blindness. Most often, glaucoma occurs in the presence of increased intraocular pressure (pressure inside the eye). However, glaucoma can also occur when intraocular pressure is normal (although treatment that reduces the pressure appears to benefit this kind of glaucoma too).
Glaucoma is the second leading cause of legal blindness in the U.S., and the first leading cause of blindness in African-Americans. Unfortunately, most of the time glaucoma presents no symptoms until permanent damage has been done. It is estimated that 2.5 million Americans have glaucoma—and half of these people do not know they have it. For this reason, regular checkups are advisable for people at high risk for glaucoma. Risk factors include:
Physicians diagnose glaucoma by measuring intraocular pressure as well as by examining the optic nerve and using special vision tests. Eye drops that reduce intraocular pressure are safe and highly effective for most cases of glaucoma.
A small double-blind, placebo-controlled trial found that use of ginkgo extract at a dose of 120 mg daily for 8 weeks significantly improved vision in people with glaucoma.8 Ginkgo is thought to work by enhancing circulation.
Small double-blind, placebo-controlled trials suggest that eye drops containing the chemical forskolin, a constituent of the herb Coleus forskohlii, reduces intraocular pressure in people without glaucoma.1,2 However there is no evidence as yet that forskolin is an effective treatment for people with glaucoma. In any case, forskolin is not available except for research, and using ordinary preparations of the herb directly in the eye is not recommended. (There is no reason to believe that oral use of Coleus forskohlii will benefit glaucoma.)
Auricular (ear) acupressure has also been studied as a potential treatment for glaucoma.9 In a small trial, 33 people with glaucoma were randomized to receive real acupressure (with massage) or sham acupressure (without massage). At weeks 3 and 4, subjects in the acupressure group did have an initial improvement in their intraoccular pressure. At weeks 2-4, their visual acuity also improved. However, the results did not last long, and there were no significant differences between the two groups.
Highly preliminary evidence suggests that certain dietary supplements may also reduce intraocular pressure, including high-dose vitamin C,3 melatonin,4 and omega-3 fatty acids.5 However, there is as yet no reliable evidence that any of these supplements enhances the effect of standard treatment, and they definitely cannot be used as substitutes for it. Weak evidence suggests that the supplement lipoic acid could improve vision in people with glaucoma.6 Magnesium has been suggested for the same purpose, but in one preliminary study, use of magnesium failed to produce statistically significant benefits.7 The herbs bilberry, ginkgo, oregano, and pilocarpus, and the supplements citrus bioflavonoids and OPCs (oligomeric proanthocyanidin complexes) are sometimes recommended for preventing or treating glaucoma, but there is no meaningful evidence to indicate that they work.
1. Badian M, Dabrowski J, Grigoleit HG, et al. Effect of forskolin eyedrops on intraocular pressure in healthy males. Klin Monatsbl Augenheilkd. 1984;185:522–526.
2. Meyer BH, Stulting AA, Muller FO, et al. The effects of forskolin eye drops on intraocular pressure. S Afr Med J. 1987;71:570–571.
3. Baxter RC. Vitamin C and glaucoma. J Am Optom Assoc. 1988;59:438.
4. Samples JR, Krause G, Lewy AJ. Effect of melatonin on intraocular pressure. Curr Eye Res. 1988;7:649–653.
5. McGuire R. Fish oil cuts lower ocular pressure. Med Tribune. 1991;19:25.
6. Filina AA, Davydova NG, Endrikhovskii SN, et al. Lipoic acid as a means of metabolic therapy of open-angle glaucoma. Vestn Oftalmol. 1995;111:6-8.
7. Gaspar AZ, Gasser P, Flammer J. The influence of magnesium on visual field and peripheral vasospasm in glaucoma. Ophthalmologica. 1995;209:11-13.
8. Quaranta L, Bettelli S, Uva MG, et al. Effect of Ginkgo biloba extract on preexisting visual field damage in normal tension glaucoma. Ophthalmology. 2003;110:359-362.
9. Her JS, Liu PL, Cheng NC, et al. Intraocular pressure-lowering effect of auricular acupressure in patients with glaucoma: a prospective, single-blinded, randomized controlled trial. J Altern Complement Med. 2010;16(11):1177-1184.
Last reviewed December 2015 by EBSCO CAM Review Board
Last Updated: 12/15/2015