Vitamin C and IOP

Most studies show that Vitamin C reduces IOP. The trick is giving enough Vitamin C.

My sources for this article are:

Alternative Medicine Review (subscription required) Volume 6, Number 2,2001, edited by Kathleen A. Head, ND.

Nutrition and Glaucoma: Do Supplements Reduce IOP ? by David Bennett BSc (Hons), MCOptom, for The Association of Optometrists Ireland.

There are several postulated mechanisms for ascorbate’s ability to lower IOP. In high doses, it acts as a potent osmotic agent. Vitamin C’s ability to halt lipid peroxidation has also been hypothesised to play a role. Supplementation with vitamin C is also believed to increase aqueous humour drainage by reducing the viscosity of hyaluronic acid in the trabecular meshwork.

Most studies, some of which were controlled, have found the supplement to successfully reduce IOP.

David Bennett says,

"In one report, a single dose of 500mg/kg ascorbic acid reduced IOP in all of 39 patients with COAG by an average of 16mmHg. Also, ascorbic acid 100-150mg/kg, three to five times daily, resulted in almost normal IOPs in 15 out of 16 patients by 45 days."

He doesn't include the source for this (it is available by request), but I think he is using the same source quoted by Kathleen A. Head.89 (see below)

He also says, "Some of these patients were uncontrollable with acetazolamide and 2% pilocarpine," but the Vitamin C was effective for them. His references are available by request but are not part of the published article. However I am fairly sure his sources are 90, 91.

In the body of his paper, David Bennett  gives one source that I did not see in Kathleen Head's paper. He says,

"In his 1980 dissertation at New York University, Ben C. Lane, a doctoral student in ophthalmology, found in a study of 60 people that increasing their average vitamin C intake from 75mg to 1200mg reduced IOP by one-third."

Kathleen Head makes the same statement as Bennett, and she provides the reference.

"Researchers first examined the effect of high dose IV vitamin C on animals and then humans, and found it successfully decreased IOP. IV doses used were in the range of 1 g/kg body weight; oral doses used were half that (500 mg/kg body weight)."89

Here are some other statements I obtained from a combination of the two articles:

Those with chronic open-angle glaucoma responded the most dramatically to Vitamin C.

The higher the initial IOP, the greater the drop after ascorbate (Vitamin C).

Decreases in pressure were maintained for as much as eight hours.

All but one patient experienced decreased IOP during a two-week trial of divided doses.

One study of oral ascorbate did not find it effective at lowering IOP in glaucoma. The researchers, however, used only 500 mg twice daily.

And these same researchers successfully lowered IOP with topical use of a 10-percent aqueous solution of vitamin C in a better follow-up study.90,91

In high doses Vitamin C acts as a potent osmotic agent.88

Vitamin C’s ability to halt lipid peroxidation has also been hypothesized to play a role.88

Vitamin C has also been found, in vitro, to stimulate synthesis of hyaluronic acid in trabecular meshwork from glaucomatous eyes.78

Ascorbate has also been found to reduce the viscosity of hyaluronic acid and increase outflow through the trabeculum. 92

We all know that high doses of Vitamin C can cause mild gastric upset and diarrhea. But these disappear in about 3-4 days. All the articles mentioned this effect. In my own case, gradually increasing the dose eliminates this problem. I find it very simple to completely avoid the possibility of this side effect. The thing I find harder is tapering down gradually after using a high dose of Vitamin C. I find my body gets used to it and doesn't want to do without it. I really do feel the benefit when taking those higher amounts of Vitamin C. However, I have not tried the levels suggested by these studies since I was diagnosed with glaucoma. I plan to do that in the near future when I can monitor my IOP very carefully.

Here is a one table from Kathleen A. Head's article. I have not asked for permission to reproduce this, so I may have to remove it. But for now, here it is:

And here is a partial list of references from Kathleen A. Head's article:

  • 78. Schachtschabel DO, Binninber E. Stimulatory effects of ascorbic acid in hyaluronic acid synthesis of in vitro cultured normal and glaucomatous trabecular meshwork cells of the human eye. Z Gerontol 1993;26:243-246
  • 88. Aleksidze AT, Beradze IN, Golovachev OG. Effect of the ascorbic acid of the aqueous humor on the lipid peroxidation process in the eye in primary open-angle glaucoma. Oftalmol Zh 1989;2:114-116. [Article in Russian]
  • 89. Virno M, Bucci MG, Pecori-Giraldi J, Missiroli A. Oral treatment of glaucoma with vitamin C. Eye Ear Nose Throat Monthly 1967;46:1502-1508.
  • 90. Linner E. Intraocular pressure regulation and ascorbic acid. Acta Soc Med Upsal 1964;69:225-232.
  • 91. Linner E. The pressure lowering effect of ascorbic acid in ocular hypertension. Acta Ophthalmol (Copenh) 1969;47:685-689.
  • 92. Liu KM, Swann D, Lee P, Lam KW . Inhibition of oxidative degradation of hyaluronic acid by uric acid. Curr Eye Res 1984;3:1049-1053.

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just had to respond.

just had to respond. Diagnosed as glaucoma suspect with IOP of 21 back in March 2007. Came back early November 2007 and IOP had increased to 25-26 both eyes. Told to put eye drops in right eye only (Travatan) one time a night before bed and come back 2 weeks later for recheck. Did a lot of reading up on glaucoma to see what I can do for myself. Anyway, just got back from eye appt. today. Now, I had only been putting the drops in the right eye, not the left. It's been untreated. I was told my eye pressure both eyes is now 19 after only two weeks. She wants me to continue with drops and come back in 3 mos. After reading on glaucoma,
I did the following things, and maybe it was a fluke that reduced eye pressure, but I think it may help me in the long run. 1. took supplements everyday specifically for eyes 2. took 1500-2000mgs of Vit.C tough on the stomach though. 3. drastically decreased my caffeine ):. One to two cups of decaf mocha only maybe every week even that, I only drank maybe a quarter of the cup. Now drinking herbal mochas..not bad at all and NO caffeine! 4. had to learn to destress somehow 5. engaged in more physical activity, working out more. Anyway, that's what I've been doing. I will keep doing what I've been doing. It seems to be doing something. It's not scientific but it seems to help.

Congratulations on your good

Congratulations on your good results. Keep up the good things you are doing. I think you are taking the right approach.

Please consider joining where we have a lot of discussions about intraocular pressure and glaucoma and improving vision.

On a related note, in my experience it is common for glaucoma medication used in only one eye to reduce intraocular pressure in both eyes. Is they why your doctor recommended that you use Travatan in only one eye?

Also, do you know about Travatan-Z (preservative free)?

Hi, I read the report on Vit.

Hi, I read the report on Vit. C. I am interested in doing this. From the article, I am taking it is okay to take 500 mg. a day. I was trying to read the 39 posts or comments, but I don't see where to do that. Can you tell me how. thanks, cathy

Hi Cathy,Thanks for your

Hi Cathy,
Thanks for your comment. To read all the posts, find the link that says "Home". Then look on the lower left side of the page and you will see a section called "Archives" with prior months listed. Click those months to read everything.

I would recommend you talk to a doctor about the Vitamin C. I'll give you a couple names in case you don't have a doctor who knows much about Vitamin C.

I'll also point out that the dose used was not 500 mg a day. It was a LOT more than that. In one study they used 500 mg per 2.2 pounds of body weight.

Here are some doctors who know about Vitamin C. (my doctor) (I am not sure if he is an expert on Vit C like the others)


I just had to respond to this

I just had to respond to this with my own personal experience for what it is worth. This certainly is not scientific evidence, just my own story.

I was dx with POAG in May. I am a breastfeeding mother so my glaucoma specialist would not give me any medication. I immediately consulted with my naturopathic who gave me some supplements. In a month my IOP's went from 28 and 29 to 24 and 25. I consulted with my naturopathic again who added a Vitamin C eye drop 2 X day. After a month and 1/2 my IOP's were 19 and 20 (that was yesterday). My glaucoma specialist claims it is just normal variations and dismisses the eye drops but I have not had a reading below 22 in a number of years. Hmmm.... For whatever it is worth, I just wanted to share this information with you.

The vitamin C eye drops are

The vitamin C eye drops are available by prescription only. One pharmacy that will make them available (upon prescription) is Key Pharmacy in Kent WA.

Here is why I do not have the

Here is why I do not have the references from David Bennett's paper. He states, "For a full set of references, email"

I got this response:

Permanent Failure: No_such_user_here
Delivery last attempted at Thu, 24 Aug 2006

Excerpt from group message: I

Excerpt from group message:

I have taken 2 grams of vitamin C for 30 years and I have read a lot of the literature dealing with its effects. Unfortunately, a lot of the literature comes from questionable sources, many written by alternative health nutcakes and many written by companies hoping to make money out of gullible readers.

@Dwight:To my knowledge, the

To my knowledge, the only studies that showed results with vitamin C used a lot more than the amount you mention (2gm/day).

A more typical dose in these studies was 500mg/kg of body weight per day. Some were twice that high.

One study that used 1 gm per day failed, but the same researchers repeated the study later with more Vit C and had success lowering IOP.

Reaching a conclusion on Vitamin C, based on the published research, is not easy. In my opinion, you not onlly need to review all the references I list on my blog, but you also (first) need to have a really solid background in the general vitamin C research, starting with Dr. Pauling's work and progressing thru the latest by Hickey/Roberts and others. Upon this foundation, the research on Vitamin C and glaucoma is one part of a fairly consistent story.

Since you mention "companies hoping to make money out of gullible readers", I want to add a few more comments:
1. Ester-C is one of those products I consider to be snake oil. The research in support of Ester-C is not good quality.
2. "Lypo-Spheric Vitamin C" is also a product I do not find compelling.
3. Dr. Cathcart, in a phone call, has recently made me question even the value of mineral ascorbates (such as Alacer Super Gram Vitamin C) - and he was the one whose research led to the formulation of that product!
4. Discussion about natural vitamin-C "complex" involves different consideration from the discussions of carotenoid complexes or vitamin B complexes. Dr. Pauling explains why, and his explanation still seems valid. Vitamin C is possibly the only nutrient that can be taken in an isolated form, in my experience. That's only my opinion, of course.

I know others have different opinions both ways. Some think vit C needs to be taken as a complex. The best research doesn't support this as far as I can see.

Others think it is OK to take any nutrients, such as beta carotene or alpha tocopherol, in isolated form. The best research is resoundingly proving this position wrong, so I think the number of scientists holding this position is rapidly declining.

5. The best (and cheapest) Vitamin C product is simply ascorbic acid.

Paul -- for non-medical ways

Paul -- for non-medical ways to reduce IOP check out

Hi, is there another

Hi, is there another over-the-counter way to reduce IOP?