Taurine is an amino acid that protects the photoreceptor cells of the retina allowing the optic nerve to process light. 
These carotenoids are found in the retina and may help protect against high-energy blue and ultraviolet light. 
From a foundational standpoint, AREDS was published in 2001, and AREDS 2 was published in 2013. During the 12-year gap between the studies, the knowledge base surrounding how nutrients may mitigate the impact of macular degeneration has grown exponentially. 
AREDS stands for Age-Related Eye Disease Study. Researchers with the AREDS published in 2001 that a nutritional supplement with the AREDS formulation can reduce the risk of developing advanced age-related macular degeneration (AMD). In 2006, the same research group, which is based at NIH’s National Eye Institute, began a second study called AREDS 2 (published in 2013) to determine if they could improve the AREDS formulation. 
Original AREDS formulation:
AREDS 2 formulation:
Why change the formulation? 
Why add lutein/zeaxanthin and omega-3 fatty acids?
Previous studies had found that dietary intake of lutein/zeaxanthin and omega-3 fatty acids is associated with a lower risk of developing advanced AMD.
Why eliminate beta-carotene?
During the AREDS trial, two large trials funded by the National Cancer Institute found that beta-carotene may increase lung cancer risk among people who smoke. Lutein and zeaxanthin are in the same family of nutrients as beta-carotene and are believed to have important functions in the retina. Therefore, the researchers theorized that lutein/zeaxanthin might be a safer and possibly more effective alternative than beta-carotene.
Why reduce zinc?
Although zinc was found to be an essential component of the AREDS formulation in the original trial, some nutritional experts recommended a lower dose.
“A confounding point is the decision by the National Eye Institute to leave the dosage of zinc at 80 mg in the AREDS 2 formula. Typically, you want to use the smallest dose you possibly can of any medication that might be effective. TOZAL contains only 25 mg of zinc because this amount has been found to be as effective as 80 mg found in the AREDS 2 formula. It’s surprising, that despite this finding, the NEI still included a higher dose of zinc rather than the lowest, most effective dose.” 
“Less surprising is the replacement of beta-carotene with lutein/zeaxanthin. An important component to TOZAL, lutein/zeaxanthin is so new to the market that the nutrients didn’t even exist during AREDS. During AREDS 2, researchers found that not only is lutein/zeaxanthin as effective as beta-carotene, it’s probably more effective.” 
“In reality, TOZAL clearly checks all of the boxes as a dietary supplement for complete ocular health and, while formulating the final product, I took the findings of AREDS 2 very seriously. TOZAL® is an AREDS 2-based formulation with some improvements – it has approximately the same amount of vitamin C, and vitamin E with an increased amount of Lutein (15 mg) and Zeaxanthin (3 mg). We reduced the amount of Zinc from 80 to 25 mg and changed to the form of Zinc from oxide to picolinate. TOZAL also includes other key ingredients, such as vitamin A, vitamin D and B-complex. Each ingredient has specific benefits that they bring to the supplement, such as assisting the retina to process low light.” 
“Most of the people who walk through my door are suffering from age-related conditions —whether it’s a 45-year-old man who needs reading glasses or a 75-year-old woman who has AMD. There are lifestyle changes that can slow AMD down or speed it up, but this is a chronic, degenerative, age-related disease. And until we find the fountain of youth or figure out how to stop aging, dietary supplements that are modeled after the AREDS 2 research, such as TOZAL, may be our best way forward,” said Dr. Edward Paul Jr. 
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