the Risk for AMD
have an opportunity to intervene in what may prove to be a major public health issue
in the second half of this century: Age-related macular degeneration (AMD). There
are four alterable
factors to consider when discussing AMD with our patients and counseling them about
1. Quit Smoking
Studies show that cigarette
smoking is a contributing factor in AMD. For patients at risk because of family
history, light skin or eye pigmentation, smoking cessation messages are particularly
important. For every one of my AMD patients, even for those in the earliest stages,
I do a pack-year calculation (number of packs per day times the number of years
of smoking). The larger the number, the greater the chance of vision loss from AMD.
Every effort at smoking cessation for these patients will help reduce their risk
A recent article (Evans et al, 2005)
projected that 28,000 cases of vision loss from AMD in the United Kingdom were directly
attributable to cigarette smoking. This convincing evidence can serve as recommendation
material for our patients who still smoke.
2. Beware Blue Light Exposure
Patients should minimize
their lifetime blue light exposure, which
is cumulative, by sunglass protection against environmental light. While selective
blue-light-absorbing lenses may be the ideal, they distort the color spectrum, which
may handicap patients who have color-vision deficits.
Studies show that blue light plays
a role in macular pigment degeneration. Fortunately, lutein- and/or zeaxanthine-pigment
supplementation may replace those damaged retinal pigments. We should offer our
patient these protective strategies at the earliest age possible.
3. Watch Your Cholesterol
A high-lipid diet may also
contribute to AMD. Many patients over the age of 60 already take statin drugs to
lower cholesterol and so have their levels under control. For those undiagnosed
or suspected because of the presence of corneal arcus, for example, recommend them
for appropriate evaluation.
4. Take Your Supplements
Finally, antioxidant and
vitamin/mineral supplements have emerged as a potential treatment for atrophic AMD.
The initial report from more than 15 years ago suggested that zinc supplementation stabilized
AMD. That, and other factors, led to the age-related eye disease study (AREDS),
which had four treatment arms: Placebo, zinc plus copper, antioxidant vitamins (A,
C, beta carotene) and combination vitamin and mineral supplementation. The bottom-line
outcome was that the combination group demonstrated about a 25 percent risk reduction
compared to the placebo group. The effect was most pronounced in patients who had
moderately advanced disease.
What about Lutein?
One criticism of AREDS was that it didn't include lutein, which at the time hadn't
achieved scientific standing. Since then, studies have shown that both lutein and
zeaxanthine, when taken orally, will show up in the blood stream and can be measured
in the macula. On the drawing board is AREDS II, which will look at previous subjects,
substituting lutein for beta carotene among the smokers and reducing the amount
of zinc recommended.
Final Word Where
does that leave us regarding vitamin and mineral supplementation advice? Antioxidant
vitamins and minerals (zinc and copper) together with lutein and/or zeaxanthine
seem to represent the foundation of a recommendation for patients at risk for AMD.
Advise caution with regard to beta carotene for patients who will continue to
For references, visit
www.clspectrum.com/references.asp and click on document #117.
Dr. Semes is an
associate professor at the University of Alabama at Birmingham School of Optometry.
Contact Lens Spectrum, Issue: August 2005