A new eye chart for the detection of glaucoma, cataracts and other eye diseases in early stages will go on the market in August. Called the Pelli-Robson Letter Sensitivity Chart, it is designed to supplement the traditional Snellen (Big E) eye chart and provides a simple way to evaluate contrast sensitivity of the eyes.
Decreased ability to detect contrast is an early symptom of many eye diseases, according to chart co-creator Denis Pelli,an associate professor of neuroscience at the Institute for Sensory Research at Syracuse University, New York.
As with the traditional chart, the eye moves down the chart. "The letters are all the same large size," said Pelli, who developed the chart with John Robson, a professor of neurophysiology at Cambridge University in England. "They start out black and as you read down the chart, they fade to lighter and lighter shades, until they finally disappear."
Loss of contrast sensitivity, experts say, can also be an early symptom of macular degeneration, diabetic retinopathy and optic neuritis.
"We believe the new chart will be useful for screening the general population," Pelli said.
High-Carb Sports Drinks
Sports drinks--beverages like Bodyfuel, Exceed and Gatorade designed to replace fluid and maintain energy during strenuous exercise--were once recommended mainly for endurance athletes who exercise continuously for 90 minutes or more. And experts cautioned athletes not to consume drinks with carbohydrate concentrations above about 2.5%.
But that thinking is changing: Some nutritionists and exercise physiologists now say such fluids might help average exercisers with shorter workouts--even 40 minutes or so--and that drinks with higher carbohydrate concentrations are OK.
The high-carbohydrate drinks were previously discouraged, said Evelyn Tribole, a registered dietitian and spokeswoman for the American Dietetic Assn., "because it was believed they didn't leave the stomach quickly enough to quench the thirsty muscles."
"But what we've seen in more recent studies is that the carbohydrate concentration can be higher (without ill effects like slow gastric emptying)," said Bill Fink, a research assistant at the Human Performance Laboratory at Ball State University in Muncie, Ind.
Recommendations vary, but Tribole said many experts now believe 5% to 10% concentrations are acceptable.
In a study of cyclists, David Lamb, director of the Exercise Physiology Laboratory at Ohio State University, compared the effects of high-carbohydrate drinks, low-carbohydrate drinks and water during rides ranging from 30 minutes to two hours. "In terms of performance, the 6% carbohydrate-electrolyte beverage was better than water and slightly better than the 2.5% beverage," said Lamb, whose study was funded by a sports drink manufacturer seeking to determine the optimal carbohydrate concentration.
Access to Medical Records
Gaining access to medical records is an often misunderstood consumer right, the California Medical Assn. says. In the July issue of California Physician magazine, spokesman Jeffrey M. Lowell spells out the rights as covered in the state Health and Safety Code sections that took effect in 1983. Among them:
- California residents are entitled to inspect and copy their own medical records (or those of their minor children or for those whom they are serving as a legal guardian) upon written request and payment of reasonable clerical costs.
- Health care specialists must respond to the request to inspect the records in five working days, unless they choose instead to provide a "summary." If they provide a summary in lieu of the entire record, they should prepare it within 10 working days of receiving the request and are permitted to charge a "reasonable" fee. They must respond to written requests to send copies of medical records in 15 days, and can charge "reasonable" copying and clerical costs.
- In certain cases, health care specialists may decline requests for mental health records.
For more information, write the California Medical Assn., P.O.Box 7690, San Francisco, Calif.94120-7690.
'Open Air' Medical Scans
A new "open air," magnetic resonance imaging system promises to make the scanning technique more practical for claustrophobic and seriously ill patients.
Physicians now use the imaging system--which employs radio waves from a high-powered magnet to produce a computer-enhanced image of a cross-section of body parts--to help diagnose joint trauma, neurological problems and other disorders.
Patients undergoing the scan must lie in a closed tunnel for about an hour, an experience that some find unpleasantly claustrophobic. Other seriously ill patients also are unsuitable for the procedure now because they cannot be left for an extended period without special care, which is difficult to administer because the scanning device's high-powered magnetic field prohibits physicians from using stethoscopes or other vital medical equipment.
But in the new "open air" system--developed by the University of California at San Francisco's Radiologic Imaging Laboratory and Diasonics Inc.--the patient reclines between two, lower-power magnets supported by four columns. The new device does not present nearly the problems with claustrophobic or seriously ill patients, experts say.
In clinical studies, the new scanner performed nearly as well as the traditional device, said Dr. William Orrison, a neuroradiologist at the University of New Mexico Hospital, Albuquerque.
He has used it on about 150 patients. His comparison of 25 traditional scans with 25 "open air" scans shows the new system is not as good at detecting lesions smaller than 2-3 millimeters. "But it's not missing clinically significant lesions," he said. "The real advantage is access to the patient. It will allow better monitoring of acutely injured and ill patients. Doctors can now go near the (open air) unit with stethoscopes, blood pressure cuffs, life support and other equipment."
The new unit could be on the market by early 1989, and is expected to sell for half the cost of the traditional system, a Diasonics spokeswoman said.