Each day, optometrists are asked by patients about ways to protect their eyes or improve their vision. Eye health is much more than new glasses. Vitamins and supplements are vital to eye health, and are often forgotten by providers. I remind my patients that a healthy diet rich in vitamins is preferable to adding additional supplements. Spinach and bell peppers are an easy addition to any diet for improved eye health.
The following list represents the opinions of the author and not Eyes On Eyecare®. For more information on similar topics, please check out our other ocular surface content!
This article, based on my reading and research on the topic, will act as a quick reference for optometrists on the latest research and vitamin supplement recommendations for specific ocular conditions.
What vitamins are good for the eyes?
Vitamin A is essential for healthy corneal development. Deficiency results from inadequate intake, fat malabsorption, or liver disorders. Vitamin A is necessary for the health of mucosal tissue, retinal phototransduction, and plays a role in the metabolism, growth and differentiation of ocular surface epithelium. Vitamin A deficiency is rare in developed countries, and is typically treated by oral supplementation.
Common signs of Vitamin A deficiency are night blindness, conjunctival xerosis, Bitot's spots, corneal xerosis, a corneal ulcer covering less than 1/3 of the cornea, a corneal ulcer covering at least 1/3 of the cornea, keratomalacia, and corneal scarring.
Fruits and vegetables are rich in vitamin A.
Retinal ganglion cells endure metabolic stress in glaucoma. In preclinical trials, B3 has demonstrated protection of ganglion retinal cells. A 2017 study on Vitamin B3 in glaucoma-prone mice indicated that the vitamin acted both “prophylactically and as an intervention.” In 2020, an additional study demonstrated Vitamin B3 supplementation improves inner retinal and improved visual field function. Future studies are dedicated to the effects of long-term supplementation.
B3 treatment for glaucoma is not currently the standard of care. More research must be done in this area before it should be recommended to patients as a supplement.
A well-balanced diet of meat, fish, and poultry, as well as avocados, peanuts, whole grains, mushrooms, green peas, and potatoes is a great natural source of B3.
What vitamins and supplements help with dry eye?
In recent studies of dry eye disease in mice models, Vitamin A is associated with a reversal of the process of squamous metaplasia as documented by conjunctival impression cytology. Clinical studies have shown that short-term supplementation of Vitamin A in patients with dry eye improves the quality of their tears.
Vitamin B12 is a cofactor in DNA synthesis and its deficit is associated with peripheral neuropathies and optic atrophy. It has also been to treat trigeminal and postherpetic neuralgia. Patients with vegan diets are often deficient in B12.
Two recent studies show improvement in dry eye patients with severe disease, with or without neuropathic ocular pain, following B12 supplementation by eye drops or IM injection.
The tear film contains high levels of Vitamin C for anti-oxidant defense and corneal wound healing. In patients with diabetes, supplementation of Vitamin E and Vitamin C was effective in improving tear production, and stabilizing goblet cell density and grade of squamous metaplasia. A randomized trial showed supplementation of Vitamins A, C, E and other herbal extracts improved Schirmer test results, tear-break up time, and corneal fluorescein staining in dry eye patients.
Patients with a vitamin D deficiency have shown to have dry eye and impaired tear function. Researchers believe that vitamin D may play a protective role by enhancing tear film parameters and reducing surface inflammation. Vitamin D also regulates cellular proliferation, differentiation and apoptosis, and enhances corneal epithelial barriers.
Additionally, it plays a role in stabilizing the lipid layer of the tear film. When patients do not get enough Vitamin D in their diets, they may begin to experience inconsistently blurry vision, eyes that burn and/or tear, and even red eyes. After 2 months of vitamin D supplementation, a recent study by Yang et al demonstrated improvement in dry eye symptoms and corneal staining.
Salmon is an excellent food for increasing Vitamin D in your diet and sunlight increases your levels.
Selenium and Lactoferrin
Selenium protein(Selenium P) is widely distributed in body tissues including the ocular surface and is reduced in patients with dry eye disease. The shortage of the protein is thought to lead to oxidative stress. Lactoferrin concentration in tears is reduced in dry eye patients. Lactoferrin protects the corneal epithelium from UV. In animal models, selenium and lactoferrin have demonstrated potential efficacy in treating dry eye disease and warrant future exploration.
Curcumin is a spice with antiinflammatory, antioxidant, antimicrobial and wound healing properties. Curcumin may inhibit fibroblast growth factor and VEGF induced by the proliferation of endothelial cells and thus neovascularization leading to hypoxia and inflammation. Study results indicate both dry eye disease and neurotrophic keratitis could be treated with curcumin.
Flavonoids are polyphenols found in fruits, vegetables, tea, cocoa, and red wine. Quercetin is the most abundant and most studied flavonoid. In mouse models, topical application resulted in an increase in tear volume, corneal regularity, and goblet cell density. It also reduces inflammatory markers and improves corneal staining.
For years, treating patients with fish oil has been the standard in eye care. In 2015, a study showed that omega-3 fatty acids may improve the signs and symptoms of meibomian gland dysfunction. Meibomian glands provide the component to balancing the tear film, the lipids that reduce ocular surface water evaporation and prevent dry eye.
The thought is that the omega-3 in fish oil reduces inflammation of the cornea, the underlying cause of dry eye. Fish oil contains two omega-3 fatty acids called docosahexaenoic acid, or DHA, and eicosapentaenoic acid, or EPA. These are thought to provide many health benefits, which include improving cardiovascular function by decreasing inflammation, mitigating peripheral artery disease, and through anticoagulation.
Additional studies have shown promising results in both weight management and cognitive function in patients with mild Alzheimer's disease.
In April 2018, the National Institute of Health (DREAM study) found that Omega-3 fatty acids taken orally are no more effective at relieving dry eye symptoms than a placebo. Patients’ symptoms were measured as their change from baseline in the Ocular Surface Disease Index. After 12 months, mean symptom scores for people in both groups had improved substantially, but there wa s no significant difference in the degree of symptom improvement between the groups.
Many researchers point out that this particular study had many problems including inconsistent dosages and sources of omega-3. Two more recent studies have confirmed the effectiveness of omega-3 in improving dry eye signs and symptoms. Recommending omega-3 for dry eye should still be the standard of care for patients.
What vitamins and supplements are good for treating macular degeneration?
Vitamin C/Vitamin E/Zinc
The goal of the Age-Related Eye Disease Study (AREDS) conducted by the National Institute of Health was to learn more about the history and risk factors of age-related macular degeneration (AMD). Results show that high levels of antioxidants and zinc reduce the risk of advanced macular degeneration. Patients with known macular changes should take a specific eye vitamin, like Ocuvite or PreserVision, that has the recommended levels of Vitamins C, E, antioxidants, and zinc.
Additionally, foods such as spinach and bell peppers, daily UV protection, and quitting smoking can possibly reduce progression.
In 2013, researchers conducted AREDS 2, adding omega-3 and lutein and zeaxanthin to the formula. Lutein and zeaxanthin were added in place of beta-carotene. Beta-carotene increased the risk of lung cancer in smokers. Omega-3 fatty acids did not show to have an effect, but lutein and zeaxanthin were shown to significantly reduce the risk of advanced AMD and vision loss.
Per the AREDs 2 study, eye vitamins for the treatment of AMD should include: 500 mg of Vitamins C, 400 Iu of Vitamin E, 80 mg Zinc, 2 mg Copper, 10 mg Lutein, and 2 mg Zeaxanthin. This remains the current standard of treatment for AMD.
A 2010 study sought to determine the effects of thiamin, riboflavin, and folate on geographic atrophy in patients with macular degeneration. Neither folate nor any B vitamin had any effect on neovascular AMD; however, high folate intake was associated with a reduced risk of progression to geographic atrophy.
In 2020, researchers continued to study the effect of supplements on disease progression. The study analyzed multiple nutrients and their effects on progression to late-stage AMD and drusen.
Vitamin A, vitamin B6, vitamin C, folate, β-carotene, lutein and zeaxanthin, magnesium, copper, and alcohol demonstrated a decreased risk in progression to late stage macular degeneration. The same nutrients seemed to protect versus large drusen and though not as extensive, neovascular AMD. Saturated fatty acid, monounsaturated fatty acid, and oleic acid demonstrated an increased risk of progression.
More research is needed to determine the best combination of vitamins to prevent progression in AMD patients.
Are there vitamins or supplements to prevent cataracts?
The theory that vitamins and supplements may prevent cataracts begins with research on free radicals. From my sources, it seems vitamins may play a role in preventing free radical damage.
However, as of 2016, short-term research has shown that vitamin supplements are not effective against cataracts. The researchers analyzed nine studies involving a total of almost 120,000 people between the ages of 35 and 85. Vitamin C, vitamin E and/or beta-carotene were used for up to 12 years by participants. The researchers considered the results of this study to be so clear that they did not see a need for any further research in this area.
Studies show that patients taking these products developed cataracts just as often as those taking a placebo. In 2020, the results of a 15-year study on the effects of vitamins/antioxidants on cataracts was released. Participants reported similar rates of cataract removal between both groups, 15% in the placebo group vs. 16% in the vitamin group.
I believe recommending healthy foods and/or prescribing vitamins and supplements is important for eye health and vision. As research evolves, it's important to be aware of new standards for treatment. AMD patients and dry eye sufferers should be recommended supplements and well-balanced diets. I feel it is vital to closely monitor the addition of B13 for treatment in glaucoma patients and other supplement additions for dry eye patients.
In my practice, I always remind patients that the best nutrients are found in the foods that we eat!