This article is for informational purposes only and does not diagnose any conditions
Vitamin E is a powerful antioxidant that is important to maintaining healthy eyes. Vitamin E has also been found to act as a helper to the nutrient lutein, enhancing its antioxidant ability to protect delicate retinal pigment epithelial cells from oxidative damage.
Vitamin E is a powerful antioxidant that is important to maintaining healthy eyes. Vitamin E works in our bodies to help form red blood cells, improve immune function and specifically in our eyes, it can help to deactivate harmful free radicals, which are atoms of oxygen that can damage cells within the body (oxidative damage). Free radicals are unstable atoms that cause damage to healthy cells when they move through the body in search of an electron to make them more stable. Research has shown that the damage caused by free radicals can lead to increased risk of cancer, heart disease and eye disease.
We increase production of free radicals when we are exposed to harmful things like air and environmental pollution, cigarette smoke and ultraviolet rays from the sun.
Vitamin E has also been found to act a helper to the nutrient lutein, enhancing its antioxidant ability to protect delicate retinal pigment epithelial cells from oxidative damage. 
Our bodies cannot make Vitamin E, so we have to ensure that we get enough from the foods we eat or supplementation.
The Age-Related Eye Disease Study (AREDS), conducted by the National Eye Institute, was a landmark study that followed participants that took specially formulated nutritional supplements and collected data about their risk of developing different eye diseases. The AREDS formulation included 500 mg of Vitamin C, 80 mg of zinc, 2 mg of copper, 28,640 IU (international units) of Vitamin A (as beta carotene) and 400 IU of Vitamin E, which is 1334% the recommended daily value of Vitamin E.  In the original study, those people with moderate to advanced age-related macular degeneration (AMD), reduced their risk of progressing to the advanced form of AMD by 25% over a period of five years, and they also reduced their risk of experiencing vision loss related to AMD by 19%.
Some studies have also shown that Vitamin E can help to reduce the risk of cataract formation (oxidation and clouding of the eye’s natural lens), while some other studies did not support this finding. A large study in Wisconsin demonstrated that people taking multivitamin supplements with Vitamins C and E had a 60% less risk of developing cataracts after five years.  Another study looked at the dietary intake of 35,000 women and those that had high lutein and Vitamin E intake has a lower risk of cataracts.  A study of African American men taking a daily synthetic form of Vitamin E supplement did not show any reduction in cataracts. 
Our bodies cannot make Vitamin E, so we have to ensure that we get enough from the foods we eat or supplementation. Most people are able to get the U.S. Recommended Daily Allowance (RDA) of Vitamin E (22.5 IU (15 mg) for people over 14 years of age) but as AREDS and other nutritional studies have shown, a higher amount (400 IU) is recommended to support good eye health. Increased Vitamin E intake is also recommended for people who smoke. 400 IU Vitamin E is what most Eye Care Professionals recommend for their patients for preventative eye care, often as part of a nutritional supplement that contains other important ingredients.
Are there different types of Vitamin E?
Yes, and the differences are important. Vitamin E can be used to describe eight different compounds called tocopherols and tocotrienols. Alpha-tocopherol is the most biologically active form of Vitamin E in our tissues and cells and the type that the body prefers to absorb and use. 
The naturally occurring forms of Vitamin E have a "d-" prefix, like d-alpha-tocopherol, and synthetic or manufactured vitamin E has a "dl-" prefix, like dl-alpha-tocopherol. The natural forms, beginning with “d” are more beneficial for our eyes and body.
Bioavailability is the term used to describe the rate and amount that a nutrient or compound is absorbed into the bloodstream, making it available to the body to use for important processes and functions. Studies have been conducted to compare the bioavailability of natural source d-alpha-tocopherol to synthetic source dl-alpha-tocopherol. This is important because many supplements contain a synthetic source of Vitamin E and people want to be sure that their bodies are getting the most benefit from the products they take. In studies that administered both types of Vitamin E at the same time and then compared the levels that are present in the blood, nearly all results showed that the natural form was close to twice the level of the synthetic, a ratio of 2 to 1.  In studies that measured the levels when natural and synthetic vitamin E were administered on separate occasions to the same individual, a ratio of 1.35 to 1 was found, still favoring the natural form. 
The National Institute of Health states that, “People need approximately 50% more IU of synthetic alpha tocopherol from dietary supplements and fortified foods to obtain the same amount of the nutrient as from the natural form.” Further adding that the RDA for natural sources of Vitamin E is 22.4 IU and the corresponding value for synthetic alpha-tocopherol would be 33.3 IU. 
How can I get enough Vitamin E?
Some great sources of vitamin E include nuts and seeds such as sunflower seeds, almonds, and hazelnuts, as well as dark leafy vegetables like spinach and collard greens. A ¼ cup serving of sunflower seeds, contains 12.5 IU of Vitamin E, 24 almonds (1 oz) contains 11.1 IU, and 1 cup of cooked spinach has 10.1 IU.
Sometimes getting everything we need from our diets can be challenging, especially reaching the 400 IU of Vitamin E recommended by AREDS. Even though a serving of sunflower seeds (12.5 IU) help to reach the recommended daily allowance of 22.5 IU, it would take 32 servings to reach 400 IU.
To ensure that you are receiving the desired amount of Vitamin E, taking a daily supplement might be the best choice. It is important to carefully read product labels to note the type of Vitamin E it contains, a natural (d-alpha-tocopherol) or synthetic form (dl-alpha-tocopherol), confirm that the supplement is of the highest quality, from a reputable company, and contains appropriate nutrient amounts and no unwanted ingredients such as dyes or fillers.
When considering a nutritional supplement it is always important to check with your physician, especially for people that have any other health concerns or are taking other medication, such as blood thinning medication or daily aspirin.
Symptoms of Vitamin E deficiency include muscle weakness, poor coordination, involuntary eye movements, nerve damage, and anemia, caused by breakdown of red blood cells.
 Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Arch Ophthalmol. 2001;119:1417-1436. https://www.ncbi.nlm.nih.gov/pubmed/11594942
 Brigelius-Flohe, R & Traber, MG (1999) Vitamin E: function and metabolism. FASEB J 13, 1145–1155. https://www.ncbi.nlm.nih.gov/pubmed/10385606
 Christen WG, Glynn RJ, Sesso HD, Kurth T, MacFadyen J, Bubes V, Buring JE, Manson JE, Gaziano JM. Age-related cataract in a randomized trial of vitamins E and C in men. Arch Ophthalmol. 2010 Nov;128(11):1397-405. https://www.ncbi.nlm.nih.gov/pubmed/21060040
 Christen WG, Liu S, Glynn RJ, Gaziano JM, Buring JE. Dietary carotenoids, vitamins C and E, and risk of cataract in women: a prospective study. Arch Ophthalmol. 2008 Jan;126(1):102-9. https://www.ncbi.nlm.nih.gov/pubmed/18195226
 Feng Z, Liu Z, Li X, et al. α-Tocopherol is an effective Phase II enzyme inducer: protective effects on acrolein-induced oxidative stress and mitochondrial dysfunction in human retinal pigment epithelial cells. J Nutr Biochem. 2010;21:1222-1231. https://www.ncbi.nlm.nih.gov/pubmed/20153624
 Hoppe PP, Krennrich G. Bioavailability and potency of natural-source and all-racemic alpha-tocopherol in the human: a dispute Eur J Nutr, 39 (2000), pp. 183-193. https://www.ncbi.nlm.nih.gov/pubmed/11131364
 Mares-Perlman JA, Lyle BJ, Klein R, Fisher AI, Brady WE, VandenLangenberg GM, Trabulsi JN, Palta M. Vitamin supplement use and incident cataracts in a population-based study. Arch Ophthalmol. 2000 Nov;118(11):1556-63. https://www.ncbi.nlm.nih.gov/pubmed/11074813
 National Institute of Health (NIH), Office of Dietary Supplements (ODS). Vitamin E for Health Professionals Fact Sheet. August 18, 2018. https://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/
 Proteggente AR, Turner R, Majewicz J, Rimbach G, Minihane AM, Krämer K, Lodge JK. Noncompetitive plasma biokinetics of deuterium-labeled natural and synthetic alpha-tocopherol in healthy men with an apoE4 genotype. J Nutr. 2005 May;135(5):1063-9. https://www.ncbi.nlm.nih.gov/pubmed/15867282