Dr. Grossman’s Blog

Researchers from Tufts University have created a model to better predict a person’s risk for Age-related Macular Degeneration (AMD). 

This study, published in the May issue of Investigative Ophthalmology and Visual Science, was based on data from the 1,446 participants in the Age-Related Eye Disease Study (AREDS).  It shows how genetic, ocular, and environmental variables were evaluated and predictive models for prevalence and incidence of AMD were assessed. 

Researchers evaluated six criteria:

• age,
• sex,
• education,
• smoking status,
• body mass index, and
• supplementation with high-dose formulation of antioxidants and zinc (to slow progression of the AMD).

Although genetics play a large part in who will get AMD, there are lifestyle choices that can greatly influence a person’s risks for AMD.  Dr. Seddon noted that among individuals with one genotype studied (homozygous C3 risk genotype), the chance of suffering from the advanced form of AMD increased from approximately three times the risk for nonsmokers to almost 10 times the risk for smokers.

Study authors hope that learning more about how to predict who is at risk for AMD will give doctors and patients better information about how to better treat and even help prevent AMD.

Learn more about AMD and AMD prevention self-help tips

SOURCE:  Prediction Model for Prevalence and Incidence of Advanced Age-Related Macular Degeneration Based on Genetic, Demographic, and Environmental Variables, Seddon, et al, Investigative Ophthalmology and Visual Science. 2009;50:2044-2053.

Antioxidant and omega-3 supplements continue to be a simple, low-cost, effective therapy for AMD

A study designed to measure changes in visual function in subjects with atrophic (dry) age-related macular degeneration (AMD) found that three-quarters of the subjects receiving a nutritional supplement demonstrated stabilization or improvement of visual acuity at 6 months.

Dry, atrophic, or non-exudative, AMD is the most common form of macular degeneration.  Risk factors for dry AMD include:

• age greater than 50
• Caucasian race
• poor nutrition
• smoking
• atherosclerotic vascular disease
• genetics 
• sunlight exposure.

Multiple studies have suggested that nutritional factors can play a significant role in slowing the onset or limiting the effects of AMD.  The Taurine, Omega-3 Fatty Acids, Zinc, Antioxidant, Lutein (TOZAL) study tried to identify the potential benefits of a new supplement designed to limit the risk of AMD and progressive vision loss.

In this study, published in BMC Ophthalmology, 37 mixed gender patients (average age 76 years) at 5 independent study sites received a nutritional supplement specifically formulated to combat AMD.   This supplement included natural beta-carotene, vitamins A and E, zinc, and copper.   Results were compared to subjects in other tests who had been given placebos.

76.7% of subjects receiving the nutritional supplement demonstrated stabilization or improvement of visual acuity at 6 months.

Read other studies about AMD

Learn more about antioxidants and food sources for nutrients important for good eye health

SOURCE:  TOZAL Study: An open case control study of an oral antioxidant and omega-3 supplement for dry AMD, Cangemi, BMC Ophthalmology 2007, 7:3doi:10.1186/1471-2415-7-3.

Age-related macular degeneration (AMD) is the leading cause of vision loss in aging Western populations.   A study measuring the benefits of lutein found that consuming lutein nutritional supplements improves visual function and symptoms in those suffering from AMD.

90 participants with AMD participated in a trial conducted at a midwestern Veterans Administration Hospital from August 1999 to May 2001.

For 12 months, patients in Group 1 received lutein supplements; in Group 2, a lutein plus an antioxidant/vitamin/mineral supplement; and in Group 3, a placebo.

Researchers found that participants in groups 1 and 2 displayed improvements in mean eye macular pigment optical density, visual acuity, and contrast sensitivity.  Patients who received the placebo had no significant changes in any of the measured findings.

The study authors concluded that visual function is improved with lutein alone or lutein together with other nutrients.

Lutein is a naturally occurring carotenoid, and is found in green leafy vegetables such as spinach and kale.

Learn more about lutein and other nutrients important for good eye health

Read more about macular degeneration (AMD)

SOURCE:  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), Stiles, et al, Optometry. 2004 Apr;75(4):216-30.

Researchers predict age-related macular degeneration (AMD) will increase substantially by 2050, as the U.S. population ages, but the use of new and existing therapies can mitigate the effects of the condition.

A significant preventative therapy named in this study is the use of antioxidant vitamins to slow the progression of AMD from early to late stages.  Other treatments reviewed include laser and photodynamic therapies and anti-VEGF injections.

Scientists from the Research Triangle Institute International in North Carolina simulated cases of early AMD, choroidal neovascularization (CNV), geographic atrophy (GA), and AMD-attributable visual impairment and blindness with 5 universal treatment scenarios:

1. no treatment;
2. focal laser and photodynamic therapy (PDT) for CNV; 
3. vitamin prophylaxis at early-AMD incidence with focal laser/PDT for CNV; 
4. no vitamin prophylaxis followed by focal laser treatment for extra and juxtafoveal CNV and anti-vascular endothelial growth factor treatment; and 
5. vitamin prophylaxis at early-AMD incidence followed by CNV treatment, as in scenario 4.

From the results of this analysis, the researchers predicted that cases of early AMD will increase from 9.1 million in 2010 to 17.8 million in 2050 across all scenarios, but that existing medical therapies have the potential to reduce the visual impairment and blindness attributable to AMD by as much as 35 percent, translating to 565,000 fewer cases of visual impairment and blindness in 2050.

Learn about good food sources of antioxidants

Read about antioxidant vitamins important in the treatment of macular degeneration

SOURCE:  Forecasting age-related macular degeneration through the year 2050: the potential impact of new treatments, Rein, et al,  Arch Ophthalmol. 2009 Apr;127(4):533-40.

Although individuals with age-related macular degeneration (AMD) lose central vision, their peripheral vision often remains intact.   The Macular Disease Society (based in the UK) has developed a training scheme to help people use the undamaged parts of their eyes to read and identify faces. 

According to their research, people can be taught to use their peripheral vision to compensate for damage to their central vision, using “eccentric viewing” and “steady eye techniques”.   When someone with central vision loss looks directly at an object it may disappear or appear distorted, but when they look above, below, or to one side of it, they see it more clearly.

Eccentric viewing helps people learn where to focus their gaze to make their vision better.  Once this position is identified, they can be taught how to read again using the steady eye technique:  instead of moving the eyes from left to right to read a sentence, the person can keep their eyes completely still and move the text to the left so that each word in turn moves into the area of best vision.

Learn more about macular degeneration

SOURCE:  BBC News Channel, April 10, 2009, http://news.bbc.co.uk/1/hi/health/7958838.stm

Long-term heavy smokers have a 2.5 to 3.5 times greater risk of losing vision from age-related macular degeneration, according to medical geneticist John R.W. Yates, Ph.D., of the University of Cambridge.

A study in the British Journal of Ophthalmology shows a strong link between smoking and age-related macular degeneration.  The study also shows the risks associated with exposure to second-hand smoke.

Researchers conducted a case-control study in four British counties to determine the relationship between smoking and either of the two forms of end-stage age-related macular degeneration — geographic atrophy and choroidal neovascularization.

Between 2001 and 2003, 435 participants with age-related macular degeneration were compared with 280 controls.  Of the 435 cases, 261 had choroidal neovascularization, 106 had geographical atrophy, and 68 had a mixed phenotype.   Smoking status was assessed by a questionnaire; smokers were defined as those who smoked at least one cigarette a day for a year.

Scientists found a statistically significant association between age-related macular degeneration and pack-years of smoking. Pack-years were defined as the number of packs smoked a day multiplied by the number of years smoked.

Specifically, for 40 or more pack-years:

• The risk was almost triple, compared with non-smokers, for age-related macular degeneration
• For choroidal neovascularization, the risk was more than double
• For geographic atrophy, the risk was more than triple.

Compared with non-smokers who weren’t exposed to second-hand smoke, the non-smokers who had such exposure had nearly twice the risk of having any form of age-related macular degeneration.

Learn more about macular degeneration including recommended self-help and nutrition to reduce your risk of blindness

Source:  “Smoking and age related macular degeneration: the number of pack years of cigarette smoking is a major determinant of risk for both geographic atrophy and choroidal neovascularization,” Khan, et al,  Br J Ophthalmol 2006;90:75-80.

A study published in the American Journal of Epidemiology suggests a diet heavy in red meat may increase the risk of age-related macular degeneration, a leading cause of blindness.

Researchers at the University of Melbourne in Australia evaluated associations between red meat and chicken intake and AMD, in a cohort study of 6,734 people aged 58 to 69.  Meat intake was estimated from a food frequency questionnaire; bilateral digital macular photographs were taken and evaluated for AMD.  Of the group, 1,680 participants had cases of early AMD and 77 had cases of late AMD.

It was discovered that participants who ate 10 or more portions of red meat each week were nearly 50 percent more likely to experience deterioration of the retina.  Participants who consumed chicken at least three times a week reduced the risk by more than 50 percent.

Study authors suggested that “different meats may differently affect AMD risk and may be a target for lifestyle modification.”

Read more about food sources for nutrients that can help prevent macular degeneration

SOURCE:  “Red Meat and Chicken Consumption and Its Association With Age-related Macular Degeneration”, Chong, et al, American Journal of Epidemiology 2009 169(7):867-876.

Researchers in the Department of Ophthalmology and Visual Sciences at the University of Wisconsin have found that risk factors for cardiovascular disease such as smoking and higher body mass index are also risk factors for age-related macular degeneration (AMD).
 
The subjects in this study were 4,288 women age 63 years and older who were participating in the Women’s Health Initiative Sight Examination (WHISE).  Using a standardized questionnaire and examinations, researchers obtained information from the women on cardiovascular disease and its risk factors.  

919 of the women in the study were diagnosed with AMD (determined by standardized grading of fundus photographs).

The results were straightforward:  women who were identified as having four important risk factors for cardiovascular disease were also significantly more likely to have AMD.  These risk factors were:

• smoking
• use of calcium channel blockers
• diabetes, and
• greater body mass index.

Learn more about macular degeneration

Read other studies about macular degeneration research and prevention

SOURCE:  Cardiovascular disease, its risk factors and treatment, and age-related macular degeneration: Women’s Health Initiative Sight Exam ancillary study, Klein, et al, Am J Ophthalmol. 2007 Mar;143(3):473-83. Epub 2007 Jan 10.

Consumption of lutein has been linked to a reduced risk of developing age-related macular degeneration (AMD).  (read studies showing the benefits of lutein for eye health ).

In order to consume the levels of lutein recommended for good eye health many people take lutein supplements.  Results from a study published in the Journal of the American Dietetic Association suggest that it may be beneficial to take supplements of lutein along with vitamin C.

Researchers from the University of Wisconsin gave young healthy men and women supplements of lutein alone, or supplements of lutein combined with vitamins C or E.  It was noted that absorption of lutein varied greatly among individuals, regardless of whether they had taken lutein alone or with vitamins C or E.  However, it was determined that lutein was absorbed significantly faster when given simultaneously with vitamin C.

Learn about lutein and vitamin C supplements, as well as food sources for nutrients essential to good eye health

SOURCE:  “Lutein absorption is facilitated with co-supplementation of ascorbic acid in young adults”, Tanumihardjo, et al, J Am Dietetic Assoc 105:114-18, 2005.

A team of Harvard researchers found that women who took a combination of folic acid and vitamins B6 and B12 had a 35% to 40% lower risk of developing age related macular degeneration (AMD) than women who took a placebo.

A group of 5442 female health care professionals 40 years or older (of whom 5205 did not have a diagnosis of AMD at the beginning of the study) received either a combination of folic acid/B6/B12 or a placebo.

After more than seven years of treatment and follow-up, 137 women were diagnosed with AMD.  Of these 137:

• 55 had been taking the supplements; 82 had been taking the placebo.
• 70 had ‘visually significant AMD’, including 26 who had been taking the supplements and 44 who had been taking the placebo.

Researchers concluded that daily supplementation with folic acid, pyridoxine (vitamin B6), and cyanocobalamin (vitamin B12) may reduce the risk of AMD.

Learn about good food sources for nutrients such as folic acid and vitamin B

Find nutritional products and supplements to supply folic acid and vitamin B

SOURCE:  “Folic Acid, Pyridoxine, and Cyanocobalamin Combination Treatment and Age-Related Macular Degeneration in Women”, Christen et al, Arch Intern Med. 2009;169(4):335-341.