Association between cannabis and the eyelids: A comprehensive review

Abstract

Cannabis is the most consumed illicit drug worldwide. As more countries consider bills that would legalize adult use of cannabis, health care providers, including eye care professionals (ophthalmologists, optometrists), will need to recognize ocular effects of cannabis consumption in patients. There are only 20 studies on the eyelid effects of cannabis usage as a medical treatment or a recreational drug. These include ptosis induction, an “eyelid tremor” appearance and blepharospasm attenuation. Six articles describe how adequately dosed cannabis regimens could be promising medical treatments for blepharospasm induced by psychogenic factors. Fourteen articles report eyelid tremors in intoxicated drivers and ptosis as a secondary effect in cannabinoid animal experimental models. The exact mechanism of cannabinoids connecting cannabis to the eyelids is unclear. Further studies should be conducted to better understand the cannabinoid system in relation to the eyelid and eventually develop new, effective and safe therapeutic targets derived from cannabis.

Effect of CannEpil® on simulated driving performance and co-monitoring of ocular activity: A randomised controlled trial

“…Oral fluid THC concentrations at 30 min also showed a strong positive relationship with blink rate, suggesting a potentially shared mechanism in acute-dosing conditions. Decreased blink duration following CannEpil consumption may be linked to increased occurrences of cannabis-induced eyelid tremors ( Hartman et al, 2016 ; Porath and Beirness, 2019 ; Porath-Waller and Beirness, 2013 ) or increased ocular irritation given the proposed involvement of cannabinoid receptors in the modulation of ocular pain and inflammation that can trigger dry eye ( Nguyen and Wu, 2019 ; Vučković et al, 2018 ). While blink rate may provide a useful indicator for recency of use, its contribution to predicting behavioural effects relevant to traffic safety are likely peripheral at best.…”

A systematic review of oculomotor deficits associated with acute and chronic cannabis use

“…Eyelid tremors demonstrate a potentially reliable biomarker in identifying cannabis‐related impairment, with good sensitivity (86%) and specificity (94%) among road users who have recently consumed cannabis 7 . Recent evidence suggests that cannabis‐induced eyelid tremors may occur due to cannabinoid receptor's role in the modulation of ocular pain and inflammation that consequently triggers dry eye symptoms 48 . While unlikely to be directly related to behavioural impairment, eyelid tremors may be a useful indicator of recent cannabis use and warrants further exploration.…”

“… 7 Recent evidence suggests that cannabis‐induced eyelid tremors may occur due to cannabinoid receptor's role in the modulation of ocular pain and inflammation that consequently triggers dry eye symptoms. 48 While unlikely to be directly related to behavioural impairment, eyelid tremors may be a useful indicator of recent cannabis use and warrants further exploration.…”

Testing for cannabis intoxication: Current issues and latest advancements

“…In addition to OLS, Hartman, Richman, et al (2016) found that FTN, MRB, and WAT tests were also strong indicators of cannabis use, with the requirement for at least two positive individual FST tests producing the highest detection rate (≥96.7%). Despite indications that eyelid tremors may be useful for identification of cannabis use in an MRB test (Nguyen & Wu, 2020), Spindle et al (2021) did not find any correlation between either the MRB or WAT tests with inhalation or oral use, adding uncertainty to the effectiveness of these FSTs. Thus, FSTs are typically used by police to screen for intoxication and to determine the need for collection of biological samples, which is a more objective method for determination use (Kintz et al, 2015; Porath‐Waller & Beirness, 2014).…”