Alternate or Complimentary Therapies for Macular Degeneration
Macular Degeneration
Related Terms
- Maculopathy
Principal Proposed Natural Treatments
- Carotenoids (such as Lutein and Zeaxanthin); Zinc with or without Antioxidants (Prevention)
Other Proposed Natural Treatments
Not Effective Treatments
- Vitamin E Alone
The lens of the eye focuses an image of the world on a portion of the retina called the macula, the area of finest visual perception. After cataracts, damage to the macula is the second most common cause of visual impairment in those over 65. Smoking, high blood pressure, and atherosclerosis are associated with macular degeneration. Bright light also appears to play a role by creating damaging natural substances in the eye, called free radicals. Gradual deterioration of the macula is called macular degeneration.
In the most common form of macular degeneration (dry
macular degeneration), a substance known as lipofuscin accumulates in the lining of
the retina. A much less common form of macular degeneration involves the abnormal
growth of blood vessels (wet macular degeneration). This can be treated
very successfully, if attended to soon enough, but may lead to irreversible blindness
if left untreated. For this reason, medical consultation in all cases of macular
degeneration (or any other type of vision loss) is essential.
Principal Proposed Natural Treatments
Note: The treatments described in this section are intended as supports to standard ophthalmalogical care, not as a substitute for it. All studies refer primarily to the more common type of macular degeneration, dry macular degeneration.
Zinc and Antioxidants
Growing evidence suggests that a mixture of zinc and antioxidants can prevent or slow the progression of early macular degeneration of the most common type.
A double-blind,
placebo-controlled trial evaluated the effects of zinc
with or without antioxidants on macular degeneration in 3,640
individuals in the early stage of the disease.1
Participants were randomly assigned to receive one of the
following treatments: antioxidants (vitamin
C at 500 mg, vitamin
E at 400 IU, and beta-carotene
at 15 mg), zinc (80 mg) and copper
(2 mg), antioxidants
plus zinc, or placebo. The results indicate that zinc alone
or, even better, zinc plus antioxidants, significantly slowed
the progression of the disease.
Note: Zinc at doses of 80 mg and higher
daily can be harmful. One of the problems is that high-dose zinc supplementation
impairs copper absorption. That's why extra copper was provided in the study described
above. However, there may be other risks as well. Physician supervision is advised. For
other dosage and safety issues, see the full Zinc
article.
Smaller studies of zinc for macular degeneration have found
mixed results.3,4
Note that it's not clear how much the antioxidants in the
mixture contributed to the benefits. A 4-year, double-blind, placebo-controlled trial
of 1,193 people with macular degeneration failed to find vitamin E alone helpful for
preventing or treating macular degeneration.16
Lutein and Other Carotenoids
Observational studies suggest that higher intake of dietary carotenoids is associated with a lower incidence of macular degeneration.5,6 Carotenoids are a group of substances that are found in many fruits and vegetables, especially yellow-orange and dark green ones. Beta-carotene is the most famous carotenoid. However, observational studies prove little about cause and effect. To determine whether carotenoids can actually prevent or treat macular degeneration, double-blind, placebo-controlled studies are necessary. (For information on why this is the case, see Why Does the Natural Pharmacist Rely on Double-blind Studies?) One such study failed to find any benefit with beta-carotene (taken along with vitamin E and vitamin C).15
The less well-known carotenoids lutein and zeaxanthin have
also been investigated for a possible role in preventing
macular degeneration (as well as cataracts).
7,8
These carotenoids, principally found in corn and dark green
leafy vegetables, are found in high concentrations in the eye.
It has been suggested that they may protect the macula from
light-induced damage by dyeing it yellow, thereby acting as a
kind of natural sunglasses. They also act in the usual
antioxidant fashion by neutralizing free radicals.9
Hopes were somewhat dampened by one observational study that
failed to find much association between the extent of macular
degeneration and the intake of either lutein or
zeathanthin.10
However, they rose again after the completion of a preliminary
double-blind, placebo-controlled trial of lutein.18
This study enrolled 90 people with dry ARMD and followed them
for 12 months. The participants received either lutein (10
mg), lutein plus antioxidants and a multivitamin/mineral
suppplement, or placebo. At the end of the study period,
participants who had taken lutein alone or lutein plus the
other nutrients showed improvements in vision, while no change
in vision was seen in the placebo group.
While these are promising findings, further study is needed
to establish the apparent benefit of lutein for ARMD. For more
information, see the full Lutein
article.
Other Proposed Natural Treatments
Flavonoids are another group of naturally occurring chemicals, found in many plants, that may offer a variety of beneficial effects. Weak but interesting evidence suggests that bilberry and OPCs, both rich in flavonoids, may prevent or treat macular degeneration.11-13
The herb ginkgo
biloba also contains many flavonoids, and is additionally
thought to increase circulation. In a 6-month, double-blind,
placebo-controlled study of 20 people with macular
degeneration, use of ginkgo at a dose of 160 mg daily resulted
in improved visual acuity.12
Furthermore, positive results were seen in a 24-week,
double-blind study of 99 people with macular degeneration that
compared ginkgo extract at a dose of 240 mg per day against
ginkgo at a dose of 60 mg per day.17
Vision improved in both groups, but to a greater extent with
the higher dose. This study would have been more meaningful if
it had included a placebo
group, but nonetheless, "dose-related" effects of this type
are good indications that a treatment really works.
Moderate wine consumption might also help prevent macular
degeneration.14
Like these herbs, wine contains high levels of flavonoids.
References
1. Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS Report no.8. Arch Ophthalmol. 2001;119:1417-1436.
3. Newsome DA, Swartz M, Leone NC, et al.
Oral zinc in macular degeneration. Arch Ophthalmol.
1988;106:192-198.
4. Stur M, Tittl M, Reitner A, et al. Oral
zinc and the second eye in age-related macular degeneration.
Invest Ophthalmol Vis Sci. 1996;37:1225-1235.
5. Seddon JM, Ajani UA, Sperduto RD, et
al. Dietary carotenoids, vitamins A, C, and E, and advanced
age-related macular degeneration. Eye Disease Case-Control
Study Group. JAMA. 1994;272:1413-1420.
6. Mares-Perlman JA, Brady WE, Klein R, et
al. Serum antioxidants and age-related macular degeneration in
a population-based case-control study. Arch Ophthalmol.
1995;113:1518-1523.
7. Landrum JT, Bone RA, Kilburn MD. The
macular pigment: a possible role in protection from
age-related macular degeneration. Adv Pharmacol.
1997;38:537-556.
8. Hammond BR Jr, Wooten BR, Snodderly DM.
Density of the human crystalline lens is related to the
macular pigment carotenoids, lutein and zeaxanthin. Optom
Vis Sci. 1997;74:499-504.
9. Snodderly DM. Evidence for protection
against age-related macular degeneration by carotenoids and
antioxidant vitamins. Am J Clin Nutr.
1995;62:1448S-1461S.
10. Mares-Perlman JA, Fisher AI, Klein R,
et al. Lutein and zeaxanthin in the diet and serum and their
relation to age-related maculopathy in the Third National
Health and Nutrition Examination Survey. Am J
Epidemiol. 2001;153:424-432.
11. Scharrer A, Ober M. Anthocyanosides
in the treatment of retinopathies [translated from German].
Klin Monatsbl Augenheilkd. 1981;178:386-389.
12. Lebuisson DA, Leroy L, Rigal G.
Treatment of senile macular degeneration with Ginkgo
biloba extract. A preliminary double-blind, drug versus
placebo study [translated from French]. Presse Med.
1986;15:1556-1558.
13. Caselli L. Clinical and
electroretinographic study on activity of anthocyanosides [in
Italian; English abstract]. Arch Med Intern (Parma).
1985;37:29-35.
14. Watson V. Wine consumption decreases
risk of age-related blindness. Medical Tribune, June 5,
1997.
15. Age-Related Eye Disease Study
Research Group. A randomized, placebo-controlled clinical
trial of high-dose supplementation with vitamins C and E and
beta carotene for age-related cataract and vision loss: AREDS
report no. 9. Arch Ophthalmol. 2001;119:1439-1452.
16. Taylor HR, Tikellis G, Robman LD, et
al. Vitamin E supplementation and macular degeneration:
randomised controlled trial. BMJ. 2002;325:11.
17. Fies P, Dienel A. Ginkgo extract in
impaired vision-treatment with special extract EGb 761 of
impaired vision due to dry senile macular degeneration.
Wien Med Wochenschr. 2002;152:423-426.
18. Richer S, Stiles W, Statkute L, et
al. Double-masked, placebo-controlled, randomized trial of
lutein and antioxidant supplementation in the intervention of
atrophic age-related macular degeneration: the Veterans LAST
study (Lutein Antioxidant Supplementation Trial).
Optometry. 2004;75:216-30.
Last reviewed March 2005 by EBSCO CAM Review Board
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