Eye Health

Nutritionally Related Eye Diseases

Age-related Macular Degeneration (AMD): Age-related Macular Degeneration slowly and painlessly reduces central vision affecting more than ten million Americans age 55 years and older. Macular degeneration is caused by the premature deterioration of the central part of the retina known as the macula. This specialized area of the retina, consisting mainly of cone photoreceptor cells, is responsible for sharp, detailed vision needed for reading, writing, seeing faces and other objects straight ahead.

Risk factors for developing AMD include: family history of AMD, a history of smoking, an inactive lifestyle, being Caucasian and the female gender. Regular dilated eye examinations are important since eyes in the early stages of AMD have few symptoms. Photoreceptor cells cannot regenerate so it is important to protect them. Steps to aid in their protection include: eating a low glycemic impact diet rich in the nutrients lutein, zeaxanthin and omega-3 fatty acids; wearing sunglasses providing UV and blue light protection; regular exercise; and, healthy weight maintenance.  Several published clinical trials including the AREDS, AREDS2, LAST, ZVF, POLA and Blue Mountain Eye Study establish the correlation between AMD and nutrition. [3] [4]

Age-related Cataracts: A cataract is a clouding of the lens inside of the eye which can lead to decreased vision. The cloudy lens is often described as similar to looking through a dirty window and causes difficulty with glare sensitivity and seeing the details of an object. Although heredity plays a role in cataract formation, certain environmental factors have been shown to increase the risk of development. Excessive exposure to bright sunlight over time, cigarette smoking, and some medications such as corticosteroids can induce cataract formation in some people. Diets rich in the carotenoids lutein and zeaxanthin, along with the omega-3 fatty acids, may reduce the risk of cataract formation.

Diabetes: Diabetes is a systemic disease that interferes with the body’s ability to use and store sugar. Excess sugar in the blood can cause damage throughout the body as well as in the eyes. In the eyes, diabetes can affect the blood vessels that support and nourish the light sensitive, neurological tissue inside of the eye known as the retina. The damaged blood vessels are weak and can leak blood and fluid, causing swelling that result in Diabetic Retinopathy.  Fluid can leak under the macula, causing swelling to this specialized area of the retina used for central vision. Macular Edema can result in blurred or lost vision and should be medically evaluated.

Nonproliferative Diabetic Retinopathy: Early stages of Nonproliferative Diabetic Retinopathy (NPDR) will have mild or nonexistent visual symptoms. This means it is extra important to have dilated eye examinations annually or more often as indicated. The more advanced form is known as Proliferative Diabetic Retinopathy (PDR).

Proliferative Diabetic Retinopathy: With PDR, circulation problems cause the retina to become oxygen deprived, stimulating new blood vessels to start growing in the retina and vitreous. These new blood vessels are weak and can leak blood into the vitreous, sometimes blocking vision. Scar tissue can form. Scar tissue can pull and distort the retina, possibly leading to a retinal detachment. Nutritionally, tighter blood sugar regulation decreases the risk for developing retinopathy as well as the severity of the retinopathy.

Diabetics are forty percent more likely to develop Glaucoma. The risk of developing Glaucoma increases with age and the number of years of having diabetes. Diabetics have a sixty percent higher incidence of developing cataracts and are likely to develop them at a younger age.

A low glycemic impact diet aimed at tight blood sugar control is critical. Choose foods that are high in antioxidants, dietary fiber and protein.

Dry Eye Disease: Nutrition and Inflammation

A healthy tear film has three layers: an inner mucous layer, a middle aqueous layer, and an outer lipid layer. All three layers are important in maintaining clear, comfortable eyes and vision. Disruption of any of these components can lead to inflammation of the ocular surface which is the hallmark of Dry Eye Disease (DED). While there are many root causes of DED, aqueous tear deficiency or excessive tear evaporation which results in the hyperosmolarity of tears is the most common cause of DED. Hyperosmolarity stimulates the production of inflammatory mediators on the ocular surface.  Medical and nutritional therapies for DED are often directed at ameliorating inflammation and symptom relief.

Vitamin A Family (Retinoids and Carotenoids): Vitamin A is essential for maintaining the well being of corneal epithelial cells. Dietary deficiency of vitamin A can lead to keratinization of ocular surfaces, keratomalacia and night blindness. The retinoids are found in animal food sources such as whole milk Greek yogurt, liver and parmesan cheese. The carotenoid beta carotene is found in plant food sources such as pumpkin, sweet potato and spinach. Vitamin A retinol is a main component of the retinal visual pigments needed for night vision, and it is also found in human tears.   

Green Tea: Epigallocatechin Gallate (EGCG), the major polyphenol in green tea, has both anti-inflammatory and antioxidant effects on corneal epithelium. One bag of green tea has 25 – 30mg of EGCG, an impressive concentration.

 

References:

[1] Nurse’s Health Study: A Prospective Study of Cigarette Smoking and Age-Related Macular Degeneration in Women, Johanna M. Seddon, MD, et.al., JAMA. 1996.

[2] Folic Acid, Vitamin B6, and Vitamin B12 in Combination and Age-related Macular Degeneration in a Randomized Trial of Women William G. Christen, OD, Sc.D, Arch Intern Med 2009 Feb. 

[3] AREDS, AREDS2: AREDS 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 Oct.; AREDS2: Age-Related Eye Disease Research Group. "Lutein/Zeaxanthin and Omega-3 Fatty Acids for Age-Related Macular Degeneration. The Age-Related Eye Disease Study 2 (AREDS2) Controlled Randomized Clinical Trial." JAMA, published online May 5, 2013

[4] LAST:  Lutein Antioxidant Supplement Trial (Richer, Stuart, et. al. –Optometry: Journal of the American Optometric Association April 2004); ZVF: Zeaxanthin and Visual Function Trial (Richer, Stuart, et. al. –Journal of Optometry 2011); POLA Study: Plasma Lutein and Zeaxanthin and Other Carotenoids (Delcourt, et. al.- Investigative Ophthalmology and Visual Science 2006); Blue Mountain Eye Study: Dietary Antioxidants and the Log-term Incidence of AMD (Tan, et.al. –American Academy of Ophthalmology 2008)

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