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Blindness

Blindness

Blindness

Description
Blindness is a severe vision impairment, not correctable by standard glasses, contact lenses, medicine, or surgery. "Legal blindness" is defined as vision with best correction in the better eye worse than or equal to 20/200 or a visual field of less than 20 degrees in diameter. The major blindness eye diseases are cataracts, age-related macular degeneration, diabetic retinopathy, and glaucoma.

Who is at Risk?
More than one million Americans are legally blind. Most blind people are 65 years of age and older and the prevalence of blindness rises sharply by age. African-Americans and Hispanics are at higher risk for blindness than Caucasians because they are at higher risk for developing diabetes, diabetic retinopathy, and glaucoma. Females and low-income families are more affected by blindness than males. It is estimated that half of all blindness can be prevented. Because most of the major blinding eye diseases do not have symptoms in their earlier stages, interventions are most useful before the disease begins to develop or in early stages of development.

Source: Centers for Disease Control and Prevention

TSRI Involved in Vision Loss Research
TSRI's Paul Schimmel, Ph.D., the Ernest and Jean Hahn Professor of Molecular Biology; Martin Friedlander, M.D., Ph.D., Associate Professor at Scripps Clinic; TSRI's Dale L. Boger, Ph.D., the Richard and Alice Cramer Professor of Chemistry; Associate Professor Glen Nemerow, Ph.D.; and Adjunct Associate Professor Gary Siuzdak, Ph.D. were recently awarded a five-year $9.6 million grant from the National Eye Institute to study the inhibitory properties of mini-TrpRS, a promising naturally occurring protein, and to develop ways to use it in patients with neovascular eye disease - specifically age-related macular degeneration (ARMD) and diabetic retinopathy, diseases that afflict tens of millions of Americans and cause catastrophic vision loss in many. Both of these eye diseases are characterized by the development of abnormal blood vessel growth in the eye. The vessels interfere with normal structures or the transmission of light to the back of the eye, impeding vision.

There is currently no effective treatment for the vast majority of these patients. The TSRI research is critically important, since vision loss does and will continue to affect the quality-of-life in our aging society. The TSRI researchers are currently attempting to develop an effective way to deliver meaningful doses of TrpRS fragments into the back of the eye to inhibit abnormal blood vessel growth.

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Preserving Vision In Macular Degeneration - Neuroprotective Effects Of Flavonoids
Macular degeneration is the leading cause of blindness in persons over 55 years of age. Thirty percent of people more than 75 years of age have macular degeneration, and the number of persons affected is expected to double as the population ages. This expected increase has led to an awareness and a sense of urgency for finding a treatment or cure. Macular degeneration affects the part of the retina known as the macula and the retinal pigment epithelium (RPE), a layer of cells that support and nourish the retina. TSRI Associate Professor Anne Hanneken, M.D. and her colleagues have explored the ability of flavonoids to prevent oxidative stress, the type of injury thought to occur in macular degeneration. This collaboration was started and the approach was validated after a large, 10-year clinical trial sponsored by the National Eye Institute indicated that antioxidants could reduce the progression of macular degeneration.

Flavonoids have several properties that make them promising candidates for the treatment of persons at high risk for macular degeneration. Specific flavonoids can enhance the production of glutathione, block the production of reactive oxygen species, and prevent the late influx of calcium; each of these activities prevents specific events in the cell death pathway. In addition, the ability of flavonoids to rescue injured neuronal cells and inhibit the growth of abnormal blood vessels give these compounds a set of unique advantages compared with other antioxidants. The long-term goal of Hanneken's research is to determine the specific classes and the chemical structures of flavonoids that are the most effective in preventing oxidative stress-induced cell death in RPE cells and other cells that are affected in common ocular diseases. The researchers found that several flavonoids can prevent cell death at low concentrations; other flavonoids have limited or no effect. Quercetin, a flavonoid present at high concentrations in yellow onions, prevents oxidative stress-induced cell death in RPE cells and has no cellular toxicity over a wide range of concentrations. Other flavonoids, including luteolin, kaempferol and taxifolin are also effective. The researchers compiled a list of the most common fruits and vegetables that contain the highest concentrations of the flavonoids that are the most effective in preventing oxidative stress induced cell death. These include spinach, wild greens, peppermint, kale, broccoli, capers, onions, hot peppers, red wine, tea, cranberries, tomato puree, citrus fruits, blackberries, cherries, and raspberries. In future studies, they will validate and expand these results.

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