Posted on

marijuana eyesight

Those tests determined that regular pot users experienced a 10-millisecond delay in the speed with which their RGCs sent key signals to the brain via the optic nerve.

The finding stems from very preliminary research involving just 52 participants, 28 of whom were regular marijuana users. That meant they used marijuana at least seven times a week.
Also, medical marijuana has been promoted as an alternative treatment for the vision-robbing condition glaucoma, because research has shown it can lower blood pressure in the optic nerve for short periods of time. However, the American Academy of Ophthalmology does not recommend medical marijuana for glaucoma patients.

The answer: Regular pot users do appear to experience a slight delay in their RGC signaling. And that could indicate impaired vision, the study authors said.
Lyons suggested that “further, more robust studies are needed to test whether long-term use of cannabis has any effect on retinal or optic nerve function.”
But Paul Armentano, deputy director of NORML, the nonprofit marijuana advocacy organization, argued that “it remains unclear at this time whether or not these findings possess any real-world significance.”
Study suggests that it might slow signaling among cells that deliver visual information to the brain
Lyons pointed to the extremely small pool of patients, as well as the lack of visual impairment symptoms prior to the study, and a lack of clarity on additional lifestyle factors that could have affected the results, such as diet and cigarette smoking history.

And, according to study author Dr. Vincent Laprevote, his team now have to “measure if this delay is permanent, or recedes with cannabis cessation.” Laprevote is a hospital practitioner at the Pole Hospitalo-Universitaire de Psychiatrie du Grand Nancy in Laxou, France.

Study suggests that it might slow signaling among cells that deliver visual information to the brain

Marijuana eyesight

In an editorial that was published in the same journal as the study, Lyons and Dr. Anthony Robson, an ophthalmologist at the University College London who was also not involved in the study, noted that the researchers examined the people’s marijuana use through urine tests, which are not as accurate as blood tests.

The researchers tested the participants’ vision and found that their eyesight was relatively good, and that no one in the study group reported having any visual problems from using marijuana such as blurred vision, according to the study, which was published today (Dec. 8) in the journal JAMA Ophthalmology.
The study included 52 people who had used marijuana at least 7 times per week during the previous month and 24 people who had never used marijuana. The people in both groups were between 18 and 35 years old. The researchers verified the marijuana use by testing the people’s urine for THC, marijuana’s main psychoactive ingredient. [7 Ways Marijuana May Affect the Brain]

It’s not clear whether this potential effect of marijuana is permanent, or would stop when a person stops using the drug, said study co-author Dr. Vincent Laprévote, a psychiatrist at Pôle Hospitalo-Universitaire de Psychiatrie du Grand Nancy in France.
Indeed, the marijuana users in the study did not experience any actual visual symptoms or changes in the quality of their vision, Lyons told Live Science.
But some experts say that the evidence presented in the study isn’t strong enough to support the link between these two factors. The cells that the researchers focused on in the study, called retinal ganglion cells, are located near the inner surface of the eye’s retina. These cells collect visual information and transmit it to the brain.
Lyons noted that although the electroretinography results suggested a difference between marijuana users and nonusers, the delay didn’t seem to translate into actual problems with the users’ vision.
In addition, there are many other factors such as tobacco use, diet and lifestyle that might affect the functioning of a person’s retinal cells, and these factors could have affected the results of the study, Lyons and Robson wrote.

More research is needed to determine whether marijuana use really is linked to changes in the functioning of those cells, said Dr. Christopher J. Lyons, an ophthalmologist at the University of British Columbia, who was not involved in the study. [Marijuana Could Treat These 5 Conditions]

Regular marijuana use may affect how well certain cells in the eye work, a small new study finds.