The importance of nutrition in the preservation of visual function and the prevention and management of eye diseases

Integrating nutritional awareness into optometric practice does not require becoming a dietitian. Image credit: AdobeStock/Naknakhone

Nutritional influences on ocular tissue integrity

The retina, particularly the macula, is one of the most metabolically active tissues in the body. Its constant exposure to light and oxygen makes it uniquely susceptible to oxidative damage. Nutrients such as lutein, zeaxanthin, and meso-zeaxanthin are selectively concentrated in the macula, where they filter harmful blue light and neutralize reactive oxygen species. Lutein and zeaxanthin are not synthesized by the human body and must be obtained from dietary sources. Meso-zeaxanthin, while less common in foods, can be synthesized in the retina from lutein.¹ Clinical trials, most notably the Age-Related Eye Disease Studies (AREDS and AREDS2), have demonstrated that appropriate levels of these antioxidants can slow the progression of intermediate to advanced age-related macular degeneration (AMD).²

Antioxidants also play a broader role across ocular structures. Vitamin C contributes to collagen synthesis in the cornea and supports the integrity of the sclera and conjunctiva. Vitamin E, a lipid-soluble antioxidant, protects photoreceptor cell membranes from peroxidative damage. These nutrients, along with zinc—a trace element essential for enzymatic antioxidant activity in the retinal pigment epithelium—comprise the foundational elements of many evidence-based ocular supplements. Together, they help maintain tissue resilience in the face of oxidative and inflammatory insults.²

Diet, inflammation, and disease progression

Chronic low-grade inflammation is a shared feature of many ocular diseases, including AMD, glaucoma, diabetic retinopathy, and dry eye. Diets rich in refined carbohydrates, saturated fats, and ultraprocessed foods contribute to systemic inflammation and glycemic volatility, which exacerbate endothelial dysfunction and neurovascular compromise in the eye. Conversely, diets high in fiber, phytonutrients, and healthy fats support anti-inflammatory pathways and improve metabolic control.

In the context of diabetic eye disease, for example, the role of nutrition extends beyond glucose management. Nutritional strategies that emphasize low glycemic index foods, w-3 fatty acids, and polyphenol-rich fruits and vegetables can reduce vascular permeability and oxidative stress in the retina. This adjunctive approach is particularly valuable in the early stages of diabetic retinopathy, when retinal changes may precede systemic symptoms and present an opportunity for lifestyle-based intervention.

Glaucoma, though classically associated with intraocular pressure, also involves mitochondrial dysfunction and impaired optic nerve perfusion. Nutritional compounds, including coenzyme Q10, magnesium, and B-vitamins, have demonstrated neuroprotective potential in both experimental and early clinical models of glaucoma.³ Nitrate-rich vegetables such as spinach and beetroot may influence intraocular pressure through nitric oxide pathways, and epidemiological data suggest that patients adhering to plant-rich, Mediterranean-style diets experience a reduced risk of glaucoma progression.⁴

The role of w-3 fatty acids in ocular surface and retinal health

Essential fatty acids, particularly w-3s such as eicosapentaenoic acid and docosahexaenoic acid (DHA), play a critical role in modulating inflammation, maintaining neural membranes, and supporting meibomian gland function. Clinical studies have demonstrated that w-3 fatty acids can improve tear breakup time, reduce ocular surface inflammation, and enhance patient-reported comfort in those with dry eye disease.⁵ DHA also plays a vital structural role in photoreceptor membranes and may offer retinal neuroprotection.

Despite their importance, w-3s are often deficient in the modern Western diet. Cold-water fish, flaxseeds, and algae-based supplements are among the few reliable sources. In optometric practice, recommending w-3 intake—whether through diet or targeted supplementation—can be a valuable, evidence-based adjunct for patients suffering from dry eye disease, macular degeneration, or even glaucoma.

Nutritional deficiencies and at-risk populations

Certain populations are at an increased risk of micronutrient deficiencies with ocular consequences. Older adults, for instance, may suffer from malabsorption, reduced dietary diversity, or medication-induced depletion of key nutrients. Vitamin A deficiency, though rare in developed countries, remains a concern in cases of malnutrition, chronic liver disease, or bariatric surgery, and can lead to xerophthalmia and night blindness.

Patients with gastrointestinal disorders, restrictive diets, or poor dietary habits may similarly lack key nutrients. For these individuals, a brief dietary assessment conducted during the case history can help identify risk and prompt referral or supplementation. While laboratory testing is not routinely performed in optometric settings, collaboration with primary care providers or integrative practitioners can support a more comprehensive management plan.

Whole-diet approaches and the microbiome

While individual nutrients have been extensively studied, dietary patterns may offer more robust protection. The Mediterranean and Mediterranean-DASH Intervention for Neurodegenerative Delay diets, both rich in plant-based foods and healthy fats, and low in processed items, have been associated with reduced risk of AMD and cognitive decline.⁶ These benefits likely stem from synergistic interactions between dietary components, rather than the isolated effects of any single vitamin or mineral.

Emerging research implicates gut dysbiosis—an imbalance in intestinal microbial communities—in the pathogenesis of several ocular conditions, including uveitis, glaucoma, and AMD.⁷ This suggests that gut health may influence immune-mediated and neurodegenerative pathways relevant to vision. Foods rich in prebiotics, probiotics, and polyphenols are being investigated for their role in reducing systemic and ocular inflammation.

Clinical integration in optometric practice

Integrating nutritional awareness into optometric practice does not require becoming a dietitian. A few simple shifts—such as asking patients about their typical diet, recommending ocular-supportive nutrients, or providing handouts on food sources of key vitamins—can add value to routine care. Educating patients about the impact of nutrition on their eye health increases adherence, improves outcomes, and fosters a more holistic patient-provider relationship.

Moreover, nutrition-focused conversations often resonate with patients who are motivated to take a proactive role in their health. As lifestyle-related diseases continue to rise, the optometrist’s role as a frontline wellness provider becomes more relevant.

Conclusion

Nutrition is not ancillary to eye health—it is foundational. As research continues to uncover the biochemical, vascular, and immunologic links between diet and vision, it is imperative that optometrists become conversant in nutritional strategies that support ocular wellness. From the prevention of disease to the preservation of visual function and the management of chronic ocular conditions, nutrition offers a powerful means to protect sight and improve patient quality of life. By embracing a more integrative model of care, optometrists can lead the way in promoting not only clearer vision but also healthier lives.

References:

1. Meagher KA, Thurnham DI, Beatty S, et al. Serum response to supplemental macular carotenoids in subjects with and without age-related macular degeneration. Br J Nutr. 2013;110(2):289-300. doi:10.1017/S0007114512004837

2. Age-Related Eye Disease Study 2 Research Group.Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial. JAMA. 2013;309(19):2005-2015. doi:10.1001/jama.2013.4997

3. Loskutova E, Shah K, Flitcroft I, Setti A et al. Lutein and zeaxanthin: the possible contribution, mechanisms of action and implications of modern dietary intake for cognitive development in children. HRB Open Research. 2019;2:8. doi:10.12688/hrbopenres.12903.1

4. Kang JH, Willett WC, Rosner BA, Buys E, Wiggs JL, Pasquale LR. Association of dietary nitrate intake with primary open-angle glaucoma: a prospective analysis from the nurses' health study and health professionals follow-up study. JAMA Ophthalmol. 2016;134(3):294-303. doi:10.1001/jamaophthalmol.2015.5601

5. Epitropoulos AT, Donnenfeld ED, Shah ZA, et al. Effect of oral re-esterified omega-3 nutritional supplementation on dry eyes. Cornea. 2016;35(9):1185-1191. doi:10.1097/ICO.0000000000000940

6. Meuer SM, Myers CE, Klein BEK, et al. The epidemiology of vitreoretinal interface abnormalities as detected by spectral-domain optical coherence tomography: the beaver dam eye study. Ophthalmology. 2015;122(4):787–795. doi:10.1016/j.ophtha.2014.10.014

7. Zinkernagel MS, Zysset-Burri DC, Keller I, et al. Association of the intestinal microbiome with the development of neovascular age-related macular degeneration. Sci Rep. 2017;7:40826. doi:10.1038/srep40826