Glaucoma and cataracts get all the news when it comes to visual impairment and blindness. That being said, attention needs to be paid to macular degeneration, since 11 million people in the U.S. and 200 million people worldwide have the disease. It is the leading cause of blindness in those age 65 and over.
Researchers are learning more about the disease and how to best treat it. At the University of Virginia, scientists found that an enzyme, cGAS, becomes activated, which leads to the killing of the cells in the retina and ultimately vision loss. This enzyme has been found to play a role in other diseases such as diabetes and lupus.
The hope is to develop drugs that would inhibit the function of cGAS. This method is similar to how statins lower cholesterol. Researchers also want to establish a way to detect the levels of the enzyme in the person’s eyes. That would allow doctors to discover the best time to administer treatment to inhibit cGAS.
Scientists are also looking at ways to decrease the risk of developing macular degeneration. The Age-Related Eye Disease Study (AREDS) sponsored by the National Eye Institute (NEI) in 2001 found that persons who were at high risk of developing advanced stages of age-related macular degeneration lower their risk by 25 percent when treated with a combination of high doses of vitamins C, E, beta-carotene and the mineral zinc. That’s not all. For those with intermediate age-related macular degeneration and those with age-related macular degeneration in one eye but not the other, this combination of vitamins and minerals reduced vision loss reduced by 19 percent. Still, don’t rush out to recommend these vitamins and minerals to all your patients. Those who didn’t have age-related macular degeneration or were in the early stages showed no benefit when they took these nutrients.
In 2006, the NEI initiated AREDS2, to see if the original AREDS formulation of vitamins and minerals could be improved with the addition of omega 3 fatty acids, lutein and zeaxanthin, as well as removing beta-carotene and reducing zinc. The study also looked at how the different combinations of the vitamins and minerals performed.
In the AREDS2 study participants took one of four formulations daily for five years. One group took the original formulation of vitamin C 500 milligrams, 400 IU vitamin E, 15 milligrams of beta-carotene, 80 milligrams of zinc and 2 milligrams of copper. There was a group that took AREDS formulation without beta-carotene. One cohort took the formulation with a lower dose of zinc (25 milligrams). Yet another took the formulation without beta-carotene and 25 milligrams of zinc. In addition to the different combinations, each group took one of the four supplements: lutein/zeaxanthin (10 milligrams/2 milligrams), omega-3 fatty acids (1,000 milligrams), lutein/zeaxanthin and omega-3 fatty acids, or a placebo. Participants with macular degeneration were monitored through the examination of retina photographs or by reviewing treatment records.
The AREDS2 study showed that adding omega-3 or other formulations does not have an effect on outcomes. The groups not given beta-carotene and those who had very little lutein and zeaxanthin in their diets (but took these supplements as part of the study) did see a benefit. Those not given beta-carotene had their risk of developing age-related macular degeneration reduced by 18 percent. Those who had little lutein and zeaxanthin in their diets before the study and then took the supplements during the study were 25 percent less likely to develop advanced age-related macular degeneration. In 2013, a report in the journal Ophthalmology from the researchers involved in this study showed that the benefits of the AREDS vitamins are long lasting. The report cites a follow up study that showed the participants were 25 to 30 percent less likely to develop advanced age-related macular degeneration.
While research in age-related macular degeneration is ongoing and other treatments are being developed, it looks like supplements might be a way to prevent vision loss.