Source Naturals Vitamin A Vision Support 10,000 IU - 250 Tablets Source Naturals Vitamin A is an essential nutrient required for normal and night vision, maintaining healthy skin, and keeping mucous membranes moist and functioning. Vitamin A is also needed by the thymus gland and the bones. There's more to good vision than meets the eye. Our eyes are extremely complex in their structure and function. Visual Eyes supports optimal eye function by influencing the multiple systems that affect vision: the brain and nervous system, antioxidant defense including macular and lens protection, liver, heart and circulation. Vitamin A Addresses the Following Body Systems Antioxidant Defense Free radicals are unstable, destructive molecules with one missing, unpaired electron. In a process called oxidation, the same process that turns iron to rust, free radicals can impact cells as they steal electrons from healthy molecules, starting a cascade that ages the body and affects the body cell by cell, tissue by tissue. This process is halted with antioxidants. Antioxidants selflessly donate their electrons to stabilize free radicals and prevent their effects. Free radicals are natural by-products of mitochondrial energy generation and they are also the result of constant bombardment by pollutants, toxins, excess sunlight, unnatural foods, and electromagnetic radiation. In 1954, Dr. Denham Haimen first espoused the Free Radical Theory of Aging. As we age, our body's ability to produce innate antioxidants decreases, giving free radicals and the aging they cause the upper hand in our bodies. Supplementation with natural antioxidants can neutralize these harmful compounds. Immune System During the Plague of the 14th century, one-third of the population of Europe died. The question is: why did the others live, even though they were also exposed to the Yersinia pestis bacteria? The answer may be the strength and responsiveness of their immune systems.