That disease is retinitis pigmentosis, a degenerative condition that destroys the millions of microscopic light sensors (known as photoreceptors) in the human eye and has no known cure. Researchers at the University of Alicante in Spain may have stumbled on an effective therapy with marijuana, which they say might be able to significantly slow down the destruction of those light sensors.
To conduct their study, the scientists gave a synthetic cannabinoid to a group of rats over a period of 90 days and found that these rats had a whopping 40 percent more photoreceptors left in their eyes than untreated rats did. Rats that were given the drug also experienced "improved connectivity between photoreceptors and their postsynaptic neurons," which receive and process light signals.
"These data suggest that cannabinoids [the active chemicals in marijuana] are potentially useful to delay the retinal degeneration in retinitis pigmentosa patients," the study notes.
This was the first time marijuana had been studied as a therapy for the disease.
But it may be too early to break out the celebratory spliffs. Researchers note in the study that they were not able to identify the exact mechanisms by which cannabinoids delay vision loss in retinitis pigmentosis patients, and they stress that more research is needed to form definitive conclusions.
The study was published earlier this month in the journal Experimental Eye Research.