The Effects of Cannabis on Visual Functions in Healthy and Retinitis Pigmentosa Patients

A Controlled Study of the Effect of Cannabis on Visual Functions in Healthy Subjects and in Retinitis Pigmentosa Patients

Medical Marijuana is used widely, and its effects on the visual system and the function of the retina have not been investigated thoroughly. Some evidence suggests that cannabinoids may be beneficial in certain degenerative diseases of the retina. The purpose of the study is To determine whether cannabis derivatives affect the visual functions in healthy adults To examine the effect of cannabis derivatives on the retina of retinitis pigmentosa patients

Twenty five healthy subjects and 25 retinitis pigmentosa patients will be recruited and will sign an informed consent form. An initial eye exam will include visual acuity and stereo vision, eye movements and eye movement recording, a full slit lamp eye exam, intra-ocular pressure measurement, visual field, OCT and electrophysiology. The subjects will receive a single sublingual dose of cannabis (THC:CBD 1:1, THC 5 mg, or THE:CBD 1:40, THC 5 mg), and will undergo the above examination again. Subjects will be monitored for 5 hours after the administration of cannabis.

retinitis pigmentosa, retinal degeneration, cannabis, THC, CBD, electrophysiology, visual functions, eye, retina

Arm 1 - healthy subjects. Arm 2 - subjects with retinitis pigmentosa All subjects will undergo a full ocular exam and visual functions will be assessed before and after the administration of a single dose of cannabis (THC:CBD 1:40). On the second study day all subjects will receive a single dose of cannabis (THC:CBD 1:1) and undergo the full ocular exam again.

All subjects will undergo a full ocular exam and visual functions will be assessed before and after the administration of a single dose of cannabis (THC:CBD 1:40). On the second study day all subjects will receive a single dose of cannabis (THC:CBD 1:1) and undergo the full ocular exam again.

All subjects will undergo a full ocular exam and visual functions will be assessed before and after the administration of a single dose of cannabis (THC:CBD 1:40). On the second study day all subjects will receive a single dose of cannabis (THC:CBD 1:1) and undergo the full ocular exam again.

Electroretinogram (ERG) - acivity of the neural retina mixed cone-rod response, cone flicker, rod response

Inclusion Criteria: consenting adults generally healthy with or without retinitis pigmentosa Exclusion Criteria: chronic or acute disease other than retinitis pigmentosa use of medication congestive heart failure recent use of illicit drugs (past month) history of drug dependency history of psychiatric disorder in subject or immediate relatives pregnancy

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Lyons CJ, Robson AG. Retinal Ganglion Cell Dysfunction in Regular Cannabis Users: Is the Evidence Strong Enough to Consider an Association? JAMA Ophthalmol. 2017 Jan 1;135(1):60-61. doi: 10.1001/jamaophthalmol.2016.4780. No abstract available.