Cannabis is one of the most prevalent drugs used worldwide. However, the neural consequences of cannabis remain poorly understood. There is a need for a rapid improvement of the scientific knowledge on the cerebral impact of cannabis use. Since the retina is an easy-to-access part of the central nervous system, it can reflect the neurochemistry of the brain.

Considering the anatomical and functional distribution of the cannabinoid system in the retinal ganglion cells, the objective of this study was to assess whether the regular use of cannabis could affect the ganglion cells functioning.

Assessment of the ganglion cells function in regular cannabis users compared to healthy controls.

Recordings of pattern electroretinogram (PERG) were performed in regular cannabis users and healthy controls using standard of the International Society for Clinical Electrophysiology of Vision (ISCEV). The amplitude and implicit time of the PERG N95 were assessed.

The N95 implicit time of PERG was significantly decreased in regular cannabis users compared to healthy controls.

We found alterations in the ganglion cells function in regular cannabis users, as showed by the increase in N95 implicit time. The ganglion cells represent the ultimate retinal relay before the visual information is relayed to the brain and, according to these results, we suppose that the signal elicited by these cells and transferred through the visual pathways is altered in cannabis users. A direct action of exogenous cannabinoids in the retinal glutamatergic transmission is discussed.

The authors have not supplied their declaration of competing interest.