Glaucoma

The term glaucoma describes a group of eye conditions that are usually associated with increased intraocular pressure (pressure within the eyeball). In many cases, the cause of glaucoma is unknown. Conventional medications are frequently effective in reducing intraocular pressure. Therefore, it is important for people with glaucoma to be under the care of an ophthalmologist.

Checklist for Glaucoma

Rating Nutritional Supplements Herbs
3Stars Vitamin C  
2Stars   Coleus
1Star Alpha lipoic acid
Fish oil and cod liver oil (omega-3 fatty acids)
Flavonoids (rutin)
Magnesium
Melatonin		 Dan shen
Periwinkle
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star An herb is primarily supported by traditional use, or the herb or supplement has little scientific support and/or minimal health benefit.

What are the symptoms of glaucoma? Because glaucoma may not cause any symptoms until it has reached an advanced and irreversible stage, regular eye exams are recommended, especially after age 40. In the later stages, symptoms include loss of peripheral (side) vision, blurred vision, blind spots, seeing halos around lights, and poor night vision. If left untreated, glaucoma may cause blindness.

How is it treated? Conventional medications in the form of eye drops and pills are frequently effective in reducing intraocular pressure, either by slowing the production of fluid within the eye or by helping excess fluid drain from the eye. If needed, surgical procedures (laser trabeculoplasty, trabeculectomy) can increase fluid drainage from the eye to relieve pressure.

Dietary changes that may be helpful: At least two older reports claimed that allergy can be a triggering factor for glaucoma.1 2 Although an association between allergy and glaucoma is not generally accepted in conventional medicine, people with glaucoma may wish to consult a physician to diagnose and treat possible allergies.

Nutritional supplements that may be helpful: Several studies have shown that supplementing with vitamin C can significantly reduce elevated intraocular pressure in individuals with glaucoma.3 These studies used at least 2 grams per day of vitamin C; much larger amounts were sometimes given. Higher quantities of vitamin C appeared to be more effective than smaller amounts.

Doctors often suggest that people with glaucoma take vitamin C to “bowel tolerance.”4 The bowel-tolerance level is determined by progressively increasing vitamin C intake until loose stools or abdominal pain occurs, and then reducing the amount slightly, to a level that does not cause these symptoms. The bowel tolerance level varies considerably from person to person, usually ranging from about 5 to 20 or more grams per day. Vitamin C does not cure glaucoma and must be used continually to maintain a reduction in intraocular pressure.

Many years ago, the flavonoid rutin was reported to increase the effectiveness of conventional medication in people with glaucoma.5 The amount used—20 mg three times per day—was quite moderate. In that study, 17 of 26 eyes with glaucoma showed clear improvement. Modern research on the effects of rutin or other flavonoids in people with glaucoma is lacking.

Supplementing with 0.5 mg of melatonin lowered intraocular pressure of healthy people,6 but there have been no studies on the effects of melatonin in people with glaucoma.

Magnesium can dilate blood vessels. One study looked at whether magnesium might improve vision in people with glaucoma by enhancing blood flow to the eyes. In that trial, participants were given 245 mg of magnesium per day. Improvement in vision was noted after four weeks, but the change did not reach statistical significance.7

Alpha lipoic acid (150 mg per day for one month) improves visual function in people with some types of glaucoma.8

Surveys have shown that Inuit people, who consume large amounts of omega-3 fatty acids, have a much lower incidence of some types of glaucoma than do Caucasians. Although there have been no studies on the use of omega-3 fatty acids to treat glaucoma, one study found that cod liver oil (a rich source of omega-3 fatty acids) reduced intraocular pressure in animals.9

Are there any side effects or interactions? Refer to the individual supplement for information about any side effects or interactions.

Herbs that may be helpful: Studies in healthy humans, including at least one double-blind trial, have repeatedly shown that intraocular pressure is lowered by direct application of forskolin, a constituent of the Ayurvedic herb Coleus forskohlii.10 11 Until ophthalmic preparations of coleus or forskolin are available, people with glaucoma should consult with a skilled healthcare practitioner to obtain a sterile fluid extract for use in the eyes. Direct application of the whole herb to the eyes has not been studied and is not advised.

Dan shen (Salvia miltiorrhiza), a traditional Chinese herb, used either alone or combined with other Chinese herbs for 30 days was reported to improve vision in people with glaucoma.12 However, the herb was administered by muscular injection, a preparation that is not readily available in North America or Great Britain. It is not known whether oral use of the herb would have the same effect.

Are there any side effects or interactions? Refer to the individual herb for information about any side effects or interactions.

References:

1. Berens C, et al. Allergy in glaucoma. Manifestations of allergy in three glaucoma patients as determined by the pulse-diet method of Coca. Ann Allergy 1947;5:526–35.

2. Raymond LF. Allergy and chronic simple glaucoma. Ann Allergy 1964;22:146–50.

3. Ringsdorf WM Jr, Cheraskin E. Ascorbic acid and glaucoma: a review. J Holistic Med 1981;3:167–72.

4. Boyd HH. Eye pressure lowering effect of vitamin C. J Orthomolec Med 1995;10:165–8.

5. Stocker FW. Clinical experiments with new ways of influencing the intraocular tension. II. Use of rutin to enhance the tension-reducing effect of miotics by reducing the permeability of the blood-aqueous barrier. Arch Ophthalmol 1949;73:429–35.

6. Samples JR, Krause G, Lewy AJ. Effect of melatonin on intraocular pressure. Curr Eye Res 1988;7:649–53.

7. Gaspar AZ, Gasser P, Flammer J. The influence of magnesium on visual field and peripheral vasospasm in glaucoma. Ophthalmologica 1995;209:11–3.

8. 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.

9. McGuire R. Fish oil cuts lower ocular pressure. Med Tribune 1991;Sept 19:25.

10. Caprioli J, Sears M. Forskolin lowers intraocular pressure in rabbits, monkeys and man. Lancet 1983;i:958–60.

11. Badian M, Dabrowski J, Grigoleit HG, et al. Effect of forskolin eyedrops on intraocular pressure in healthy males. Klin Monatsbl Augenheilkd 1984;185:522–6 [in German].

12. Zhen-zoung W, You-qin, Su-mo Y, Ming-ti X. Radix Salviae miltiorrhizae in middle and late stage glaucoma. Chin Med J 1983;96:445–7.