Cocaine Eyedrops Used To Detect Parkinson's

Doctors might someday use cocaine to diagnose Parkinson's disease in a rather unconventional way: via drops to the eye. By comparing the amount of pupil dilation caused by an eye drop used in ophthalmology offices to dilation from a cocaine eye drop, researchers in Japan said they could accurately identify people with Parkinson's. At present, there is no specific diagnostic test for Parkinson's disease, which is caused by the gradual death of brain cells producing the neurotransmitter dopamine. Symptoms of this motor system disorder include tremor, trembling, rigidity or stiffness, slowness of movement and imbalance. "Unfortunately, there is no clear way to diagnose Parkinson's," said Dr. Spriridon Papapetropoulos, an assistant professor of neurology at the University of Miami School of Medicine. "As we speak, the diagnosis remains clinical," which means the physician must use various criteria to figure it out. Some tests are available, including a smell test, but they are unreliable and rarely used, he said. The current findings are far from definitive, however. "This eye drop test is a potential diagnostic tool for Parkinson's disease," said Dr. Shun Shimohama, senior author of a research letter published in the Feb. 23 issue of the Journal of the American Medical Association. However, he pointed out that autonomic neuropathy -- damage to the nerves that regulate the involuntary part of the nervous system -- may affect the results. Also, the size of the study was small, he added.