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INTERNET PILOT STUDY SHOWS
IMPROVED VISION IN RETINITIS PIGMENTOSA PATIENTS
Contact: Susan Thomas, (314) 991-4100 ext. 263, email SLThomas@theaoa.org
From the American Optometric Association
St. Louis, March 23, 2000 — A six-month study of individuals with retinitis pigmentosa (RP), recruited and monitored via the Internet, concludes that supplementation with the nutrient lutein may improve vision, at least over the short term, according to an article in this month's issue of Optometry: Journal of the American Optometric Association.
Retinitis pigmentosa is a group of diseases that cause degeneration of the retina, the thin layer of tissue that lines the inside of the back of the eye. The damage begins with the light-sensitive rod cells, causing loss of night vision. As the disease progresses over several decades, peripheral vision gradually disappears, but most patients retain a small island of central vision; patients with severe RP eventually lose all their sight. Approximately 100,000 Americans have RP and closely related retinal disorders. In most cases, the disease is caused by an inherited genetic defect, and there is currently no cure.
The study, by principal author Gislin Dagnelie, Ph.D., Assistant Professor of Ophthalmology at the Johns Hopkins University School of Medicine, and two co-authors afflicted with RP, looked at the effects of lutein supplementation on visual acuity and central visual field area in an international population recruited via an Internet mailing list. Lutein, a carotenoid found in the human retina, is derived from the diet, primarily from dark green leafy vegetables and egg yolk. Its antioxidant properties are thought to inhibit free radical damage caused by light (blue and ultraviolet) and oxygen. "Several studies have reported an association between dietary intake of carotenoids and lowered incidence of age-related macular degeneration," said Dr. Dagnelie. "With the proliferation of anecdotal reports in consumer media, on World Wide Web sites, and in Internet chat rooms and mailing lists, many unconventional treatments have found followers among RP patients hoping for a cure, or at least relief from the degeneration process. We had the opportunity to take a more scientific approach when one of my co-authors, participating in an Internet RP mailing list, noticed that several fellow list members reported clearing of their vision after taking daily lutein supplements. We then designed two home vision tests and recruited subjects."
All 16 participants in the study took lutein at breakfast, 40 mg daily for two months, and 20 mg daily for the remaining four months. In addition, half of the participants took DHA (a polyunsaturated fatty acid primarily found in fish oil), vitamin B complex, and digestive enzymes.
Starting two weeks ahead of these supplements, participants began self-testing their visual acuity on the computer screen with a set of six specially created letter charts in the form of Microsoft Word® files. "Our participants viewed these charts at arm's length, and a helper noted how many of the letters, from 72 to 7 points, were seen correctly," explains Dr. Dagnelie.
To test central vision, each participant received instructions on how to make a wall chart. "Basically, we told them to make horizontal and vertical lines with half-inch markings, in the form of a cross, on a sheet of paper at least 30 inches high and wide. A helper then moved a black pen inward from the four edges of the chart, noting where along each line the participant first saw the pen."
The results indicate that most participants registered a significant improvement in both visual acuity and central visual field area, as early as three to four weeks after starting the supplementation. "There appeared to be no difference between the two supplement regimens, but in addition to the overall benefit we did find two puzzling relationships: blue-eyed participants had substantially higher gains in visual acuity than dark-eyed participants, and those already taking other supplements prior to the study—notably vitamin A and/or beta-carotene—had substantially greater visual field benefits," according to Dr. Dagnelie.
The authors feel that this is only a starting point for further research. "A larger, placebo-controlled study will be needed to confirm and further investigate the effects reported here. More importantly," says Dr. Dagnelie, "the long-term effects of lutein supplementation on the progression of RP need to be investigated."
Date last modified 6/4/2000