April 24, 2008

3 Min Read
Science Beat

Vitamin C May Help Lasered Eyes
Although customized photorefractive keratectomy (laser eye surgery) for myopia has been gaining popularity, it still carries the risk of corneal haze. Late-onset haze that develops four to 12 months after PRK may lead to permanent scarring, which can damage eyesight and cause glare.

Now a preliminary Norwegian study conducted by Aleksandar Stojanovic, M.D., of the University Hospital of North Norway, suggests vitamin C supplements may prevent this haze development. Stojanovic compared a group of 212 people who had PRK between 1996 and 1998 but did not take vitamin C with a group of 152 people who received the surgery between 1998 and 2000 and took vitamin C. The supplementing group took 500 mg twice a day one week prior to surgery and for two weeks after surgery. Haze was evaluated at one day, one week, three months and six months and was graded on a scale of zero to four. Late corneal haze was defined as an acute haze of grade 2 (moderate, with difficult refraction) or higher beginning at least four months after treatment. None of the people in the vitamin C group developed late corneal haze, but 3.5 percent of those in the nonsupplemented group did—a statistically significant difference. Higher myopia correlated with an increased haze risk.

Eye tissue is rich in vitamin C, but the mechanism by which the vitamin protects is unknown. Based on these results, Stojanovic suggests a randomized, double-blind study.

Journal of Refractive Surgery May/Jun 2003; 19(3);338-43

Quercetin May Prevent Fibrosis
Results of a tissue culture study suggest quercetin may be effective against excess scarring, or fibrosis. Fibrosis can cause problems in many areas of the body. Externally, it creates unsightly, raised keloid and hypertrophic scars after burns or other injuries. Internally, fibrosis causes life-threatening liver cirrhosis and kidney glomerulonephritis. In fibrosis, the cells that make scar tissue, or fibroblasts, are overactive. They multiply excessively, making too much collagen lattice, which contracts to form the three-dimensional scar. Currently, there is no satisfactory way to prevent or treat fibrosis.

To see if quercetin might help, Toan-Thang Phan, M.D., of the National University of Singapore, took tissue samples of fibroblasts from keloid and hypertrophic scars as well as from normal skin. He applied several types of natural compounds to the tissues and observed the results. Quercetin strongly inhibited the multiplication of keloid scar tissue cells but not the normal fibroblasts, in a dose-dependent manner. After the quercetin was removed from the environment, the keloid fibroblasts slowly resumed reproduction. Quercetin also normalized the collagen lattices so they did not contract. Other compounds, including curcumin from turmeric, also inhibited abnormal scarring, but quercetin was the most effective.

Fatty Acid Supplements for Babies After Weaning
Giving fatty acid supplements to babies after they are weaned improves their eyesight, according to results of a double-blind study conducted by Dennis R. Hoffman, Ph.D., from the Retina Foundation of the Southwest in Dallas. The study included 61 babies who were breast-fed until they were 4 to 6 months old, and then were given commercial infant formula. Half of the babies were given Enfamil with iron; the others received the same formula supplemented with the fatty acids docosahexaenoic acid, an omega-3 fat, and arachidonic acid, a long-chain omega-6 fat. When the babies were a year old, their eyesight was measured. Those receiving the fatty acid-enhanced formula performed better on the visually evoked potential test, which measures overall eyesight response, than the babies who drank the regular formula, rating 0.152 compared with 0.255. (The numbers are on a logarithmic scale, with lower numbers showing more mature visual function.) The groups performed equally on tests measuring how the two eyes work together.

Breast milk contains more DHA and arachidonic acid than commercial infant formula, and eye tissue is also extremely rich in both fatty acids. Hoffman concludes that babies should be breast-fed until they are a year old. If they are weaned earlier, they should take fatty acid supplements to optimize visual development.

Natural Foods Merchandiser volume XXIV/number 10/p. 50

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