The retina is especially sensitive to free radical damage. Throughout the day, it is continuously exposed to environmental situations that are known to trigger an increase in free radical formation – exposure to natural sunlight, high levels of oxygen (many free radicals are formed from oxygen), high concentrations of omega-6 fatty acids in the diet (which can become unstable and generate free radicals) and the harmful effects of blue light, like that emitted from smart phones, tablets, computers, and TVs.
As we age, the cumulative effects of all of these factors can create problems with focus, color differentiation, and night vision.
Fortunately, supplementing with two key carotenoids, lutein and zeaxanthin, may provide a way to improve night vision and protect the delicate structures of the eyes. For those who struggle with night driving, and in other low-light situations, the nutrients could literally be a life saver.
The National Highway Traffic Safety Administration (NHTSA) reports that the fatality rate for older Americans is 17 times higher than the 25 to 65 age group. Much of that difference can be due to the way eyes recover more slowly from light glare (think of driving at night in the rain or on a wet highway) and from a reduced ability to see contrasts as clearly in low light.
The reason why lutein and zeaxanthin are so important is because they are naturally concentrated in the layers and pigments of the macula, the part of retina where incoming light and images are focused in the eye. While a diet with fruits and vegetables that are rich in carotenoids can help prevent vision loss, many people simply don’t get enough of these nutrients through diet alone.
This double-blind, placebo-controlled clinical study found that supplementing with both lutein and zeaxanthin improved glare recovery time, increased the ability to complete visual tasks in low light, and reduced night driving crash risk in just six months.
Richer S, Novil S, Gullett T, Dervishi A, Nassiri S, Duong C, Davis R, Davey PG. Night Vision and Carotenoids (NVC): A Randomized Placebo Controlled Clinical Trial on Effects of Carotenoid Supplementation on Night Vision in Older Adults. Nutrients. 2021 Sep 14;13(9):3191.
Twilight and low luminance levels are visually challenging environments for the elderly, especially when driving at night. Carotenoid rich diets are known to increase macular pigment optical density (MPOD), which in turn leads to an improvement in visual function. It is not known whether augmenting MPOD can lead to a decrease in vision related night driving difficulties. Additionally, it is unknown if carotenoid supplementation provides additional measurable benefits to one's useful field of view (UFOV) along with a decreased composite crash risk score. The aim of the study was to evaluate changes in night vision function and UFOV in individuals that took carotenoid vitamin supplements for a six-month period compared to a placebo group.
Methods: A prospective, randomized, double-blind, six-month trial of a 14 mg zeaxanthin/7 mg lutein-based supplement was carried out. Participants were randomized into active or placebo group (approx 2:1).
Results: n = 33 participants (26 males/7 females) participated with 93% capsule intake compliance in the supplemented group (n = 24) and placebo group (n = 9). MPOD (mean/standard error SE) in the active group increased in the Right eye from 0.35 density units (du)/0.04 SE to 0.41 du/0.05 SE; p < 0.001 and in the Left eye from 0.35 du/0.05 SE to 0.37 du, p > 0.05). The supplemented group showed significant improvements in contrast sensitivity with glare in both eyes with improvements in LogMAR scores of 0.147 and 0.149, respectively (p = 0.02 and 0.01, respectively), monocularly tested glare recovery time improved 2.76 and 2.54 s, respectively, (p = 0.008 and p = 0.02), and we also noted a decreased preferred luminance required to complete visual tasks (p = 0.02 and 0.03). Improvements in UFOV scores of divided attention (p < 0.001) and improved composite crash risk score (p = 0.004) were seen in the supplemented group. The placebo group remained unchanged.
Conclusions: The NVC demonstrates that augmenting MPOD in individuals with difficulty in night vision showed measurable benefits in numerous visual functions that are important for night vision driving in this small sample RCT. Additionally, we observed an improvement in UFOV divided attention test scores and decreased composite risk scores.
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