Although clinical studies have not yet proven that nutritional
supplements play a role in glaucoma, optometrists are increasingly interested
in discovering alternative therapies for this disease. Supplements such as
ginkgo biloba, resveratrol, fish oil and co-enzyme Q10 are among the most
promising treatments, according to our sources.
When looking toward alternative and complementary therapies, Primary
Care Optometry News Editorial Board Member Murray Fingeret, OD, said
clinicians are trying to discover new treatment methods that protect the optic
nerve, not just lower IOP.
“We know glaucoma is not due to having too much aqueous in the eye
and yet we treat it by just lowering the IOP and releasing the aqueous,”
he said in an interview. “When we talk about complementary or
supplementary ways to deal with glaucoma, we are looking at ways to get to the
core reason why glaucoma damage develops. We believe there are parallels in
terms of why glaucoma and other neurodegenerative diseases develop, which is
why ginkgo or resveratrol may be significant.”
Neurodegenerative disease
The parallels between glaucoma and diseases such as Alzheimer’s and
macular degeneration have been noted in an unpublished paper by Robert Ritch,
MD, FACS, FRCOphth, and Joseph R. Zelefsky, MD. In an interview, Dr. Ritch
explained that these neurodegenerative disorders share similar attributes that
he believes can be improved with supplementation.
“All of these diseases are characterized by a low grade
inflammatory component, oxidative damage, mitochondrial dysfunction and
glial-hyperactivity. So what’s good for one of these diseases should be
good for all of them, outside of the specific things such as lowering
IOP,” Dr. Ritch told PCON.
Glaucoma, which Dr. Ritch defines in his paper as a progressive optic
neuropathy characterized by a specific pattern of optic nerve head and visual
field damage, causes vision loss when the retinal ganglion cells are killed by
apoptosis. The aim of neuroprotection in glaucoma, he writes, is to slow the
progression by blocking the mechanisms that lead to apoptosis.
The argument for ginkgo
According to Dr. Ritch, ginkgo biloba extract appears to have many
properties related to the treatment of pressure-independent risk factors for
glaucomatous damage.
“Ginkgo provides everything you would want from a neuroprotectant
for glaucoma,” he said. “It inhibits inducible nitric oxide synthase,
glutamate-excito toxicity and lipid peroxidation of membranes. It preserves
mitochondrial morphology from aging changes and preserves mitochondrial ATP
production. It improves the blood supply to the periphery, the brain and the
eye.”
While PCON Editorial Board member Alan M. Robin, MD, acknowledges
benefits of ginkgo biloba, he feels more studies are needed in humans to prove
the link to glaucoma.
“Ginkgo has never been proven in a masked study to be better than a
placebo,” Dr. Robin told PCON “And, in many people, it can cause
serious problems with blood clotting.”
PCON Editorial Board member J. James Thimons, OD, tells his
glaucoma patients to maintain good nutrition and take supplements such as
ginkgo biloba and co-enzyme Q10.
“Many good clinicians have worked hard to understand the role of
ginkgo in glaucoma and recommend its use in patients who have glaucoma that is
not necessarily related to IOP,” he said. “A patient with a
normal-tension glaucoma diagnosis usually has something other than just a
pressure-related concern; there’s usually an underlying vasculopathic
process.
“They have Raynaud’s disease, they get severe migraines, they
have extremely low blood pressure or they may have clotting dysfunction,”
he continued, “so the use of an agent that increases blood flow by
decreasing platelet stickiness actually makes a lot of sense from a purely
mechanistic perspective.”
Resveratrol as antioxidant
Originally discovered as the component in red wine that contributed to
the “French Paradox” – the theory that red wine consumption is
responsible for the low incidence of heart disease in the French despite a rich
diet – resveratrol is found in the skin of red grapes and has been widely
studied for its antioxidant properties.
According to Brisdelli and colleagues, “Resveratrol is a naturally
occurring polyphenol that shows pleiotropic health beneficial effects,
including antioxidant, anti-inflammatory, anti-aging, cardioprotective and
neuroprotective activities.”
These properties make it an effective alternate therapy for glaucoma,
Dr. Ritch writes, because of its ability to activate sirtuins, a family of
proteins that play an important role in chromosomal stability and longevity.
“A single infusion of resveratrol can elicit neuroprotective
effects on cerebral ischemia-induced neuron damage through free radical
scavenging and cerebral blood elevation due to nitric oxide release,” Dr.
Ritch’s paper reads. “Its antiapoptotic activity has led to the
suggestion that resveratrol may make a useful dietary supplement for minimizing
oxidative injury in immune-perturbed states and human chronic degenerative
diseases.”
Dr. Fingeret commented, “Resveratrol is fascinating. If you look at
anti-aging and anti-oxidation, there’s a very strong case for it. However,
I’m not aware of anything specifically that links it to being a glaucoma
agent.”
Fish oil
A study by Nguyen and colleagues is one of the best arguments for fish
oil, Dr. Fingeret said. The study found that rats fed omega-3 fatty acids had
an improvement in ganglion cells, which play a pivotal role in the function and
health of the optic nerve.
“The paper showed that taking fish oil actually lowered IOP,”
Dr. Fingeret said. “However, you need more than an animal model to support
telling a patient to take it; you need human studies.”
Dr. Thimons also hailed the anti-inflammatory properties of fish oil.
“There’s good evidence to suggest that omega-3 fatty acids are a
potential long-term mechanism to combat the inflammatory damage that produces
glaucoma,” he said. “It makes sense because omega-3 is a natural,
low-grade, constant source of inflammatory control in the human body.”
Co-enzyme Q10
According to Dr. Thimons, another drug that plays a significant role in
metabolic function is co-enzyme Q10.
“Co-enzyme Q10 is a good drug for a variety of issues, and it
promotes a much better metabolic function in all tissue levels, including
neural tissue,” he said. “It’s been well established that it is
useful to a patient’s overall metabolic health, particularly as it relates
to the replacement of cells within the neuro complex.”
According to Dr. Ritch’s paper on natural compounds, co-enzyme Q10
“may be beneficial in glaucoma, as [it] has been shown to prevent
apoptosis in retinal ganglion cells subjected to ischemia by limiting the
release of glutamate.”
More studies needed
Despite optometrists’ increasing interest in this area, our sources
agree that more research is needed.
“These are expensive studies to conduct, and drug companies
don’t have an interest in this right now,” Dr. Fingeret said.
Dr. Robin said optometrists should carefully consider how alternative
therapies might adversely affect a patient’s health. In addition, one
brand of ginkgo may not contain the same formulation as another, resulting in
different absorption rates, dose response curves and side effect profiles.
“You have to make sure these compounds are checked out with their
primary care physician,” he said. “Just because it’s a natural
supplement doesn’t mean it’s safe and effective. You have to make
sure these therapies do not interact with other medications patients might be
taking.”
For more information:
- Murray Fingeret, OD, is chief of the optometry section at the
Department of Veterans’ Affairs Medical Center in Brooklyn and Saint
Albans, N.Y., and a professor at SUNY College of Optometry. He is also a member
of the Primary Care Optometry News Editorial Board. He may be contacted
at St. Albans VA Hospital, Linden Blvd. and 179th St., St. Albans, NY 11425;
(718) 298-8498; fax: (516) 569-3566; e-mail:
murrayf@optonline.net.
- Robert Ritch, MD, FACS, FRCOphth, is the Shelley and Steven Einhorn
Distinguished Chair in Ophthalmology and can be reached at the New York Eye and
Ear Infirmary, 310 East 14th Street, New York, NY 10003; e-mail:
ritchmd@earthlink.net.
- Alan M. Robin, MD, is an associate professor of ophthalmology and
international health at Johns Hopkins University and a member of the
PCON Editorial Board. He can be reached at 6115 Falls Rd., Ste. 333,
Baltimore, MD 21209-2226; (410) 377-2422; fax: (410) 377-7960; e-mail:
arobin@glaucomaexpert.com.
- J. James Thimons, OD, is a PCON Editorial Board member and
chairman of the National Glaucoma Society. He can be reached at Ophthalmic
Consultants of Connecticut, 75 Kings Highway Cutoff, Fairfield, CT 06430; (203)
257-7336; fax: (203) 330-4958; e-mail:
jthimons@sbcglobal.net.
References:
- Brisdelli F, D’Andrea G, Bozzi A. Resveratrol: A natural
polyphenol with multiple chemopreventive properties. Curr Drug
Metab. 2009;10(6):530-546.
- Nguyen CTO, Vingrys AJ, Bui BV. Dietary omega-3 fatty acids and
ganglion cell function. Inves Ophth Vis Sci. 2008;49:3586-3594.
- Zelefsky JR, Ritch R. Natural compounds: Evidence for a protective
role in eye disease. Unpublished, 2009.