Chat Highlights
Nutrition and Glaucoma
January 17, 2001

Norma Devine, Editor

On Wednesday, January 17, 2001, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Nutrition and Glaucoma." 

Moderator:  Hello, Dr. Rick.  The topic tonight is "Nutrition and Glaucoma."  Is there much information about that?  

Dr. Wilson:  Unfortunately, we don't know as much about nutrition and glaucoma as we would like.  Mega doses of vitamins do not seem to make a noticeable difference.  Certainly the general health of the patient, especially older patients, is crucial to resisting the deleterious  effects of glaucoma.  Nutrition plays a role in that.  Theoretically, Vitamin E can improve the optic nerve's ability to resist intraocular pressure, but this has not been proven in human beings.  Nevertheless, I advise my patients with normal-tension glaucoma (NTG) to take 400 IU of Vitamin E per day.

P:  I have NTG, and my blood pressure is 90/60.  I have increased my salt intake, but don't know how much to take. Any guidelines?

Dr. Wilson:  I, personally, have never prescribed tablets.  Dr. Selim Orgul of Switzerland recommends starting with one gram of salt at bedtime and increasing to up to three times per day.

P:  What about our intake of fluids? 

Dr. Wilson:  There are only moderate limits to  the amount of fluids that can be consumed, as long as the fluid is spread evenly throughout the day and not loaded on the body in a short period.

P:  Should glaucoma patients not drink 64 oz. of  water per day, as is often recommended for good health?

Dr. Wilson:  You should drink plenty of fluids, six to eight glasses a day are recommended.  You should not drink three glasses in an hour unless you are dehydrated.

P:  Is zinc contraindicated?

Dr. Wilson:  Zinc is not contraindicated, but absorption of zinc is linked to copper, as I understand it.  Increasing the zinc intake will displace copper, and may be harmful.  Zinc has also been linked to Alzheimer's disease, so I would not use much more than the RDA (recommended daily allowance).

P:  I'm assuming the RDA is way above the amount in cold lozenges containing zinc.  I find that  Coldeze is effective in diminishing the intensity of a cold,  or even preventing a cold, if taken  when symptoms are first noticed.  

Dr. Wilson:   That is an acute intervention, not chronic usage. The zinc in the cold lozenge is way above the RDA.

P:  So you're saying it should be avoided, if possible?

Dr. Wilson:   Not avoided, but not used much above the RDA. Taking cold lozenges for several days would probably be fine.

P:   Doctor, how about vitamin B12?

Dr. Wilson:  Vitamin B12 should not be overly helpful unless you have pernicious anemia.

P:  Is vitamin B12, 250 mcg daily, harmful in any way if I decide to continue taking it ?

Dr. Wilson:   Not that I know of.  

P:  What is your opinion about ginkgo biloba? 

Dr. Wilson:  Ginkgo biloba has several proponents. Most of the glaucoma community would like to see a well-designed study before putting our patients on ginkgo.  If you are interested, Bob Ritch (Dr. Robert Ritch, New York Eye and Ear) is a strong proponent of it and has information on his website concerning it.

P:  Is lutein, touted for macular degeneration patients, of any benefit to us?

Dr. Wilson:  Not that I can tell.

Moderator:  What if I maintain a bad diet?  Will it make my glaucoma worse?

Dr. Wilson:  A diet bad enough to hurt your health would probably minimize your resistance to elevated IOP when you get older.

P:  Is there any evidence that diet alone can influence the production or viscosity of aqueous?

Dr. Wilson:  Not that I have heard.  Inflammation will increase the viscosity of the aqueous, making it harder for the eye's fluid to exit the globe.

P:  Are there any foods that are particularly good for glaucoma?

Dr. Wilson:  I don't know for sure, but kale, spinach and all those green leafies, along with carrots, are great for the retina and probably good for the eye as well. Green tea is full of  free radical scavengers, as well.  These are all recommended for macular degeneration, and since it is the ganglion cells of the retina that are damaged with the nerve axons in glaucoma, they should be beneficial.  Green tea does have some caffeine in it, if you are sensitive to caffeine, but not as much as black tea.  

P:  I eat a lot of romaine lettuce, but I never hear that mentioned as one of those green, leafy vegetables. 

Dr. Wilson:  Romaine lettuce is better than Iceberg,  but it is still mostly water. The stronger the greens, the more effect.  Kale is the best, but is pretty strong.  Spinach is my favorite among the good guys.

P:  Do caffeine and alcohol have any effect on intraocular pressure?  

Dr. Wilson:  Caffeine does not.  Alcohol lowers IOP for an hour or two, due to the diuretic effect. 

P:  Is there a link between being overweight and certain glaucomas?

P:  Good question.  I looked around my glaucoma doctor's waiting room and everyone was very thin.  There were no heavyweights.

Dr. Wilson:  There is a link between obesity and glaucoma. Obesity is a big part of the problem of hypertension in this country. Over the course of two years, patients with systemic hypertension will show a rise in their IOP.  

P:   Can you elaborate on the connection between losing weight and lowering IOP?

Dr. Wilson:  Every pound of fat contains a mile of capillaries (blood vessels).  Losing weight has consistently resulted in lowering eye pressure if a significant amount of weight is lost.  Exercise helps IOP and weight loss.

On January 24, Dr. Wilson discussed "Managing Your Glaucoma" in the Chat room. Click here for highlights of that meeting.

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