# Influence of Cannabidiol Use on Visual Function and Optical Quality: A Randomized Controlled Trial

> **Author:** Benjamin Caplan, MD (ABFM Board Certified, MA Lic. #240562, NPI: 1962722637)
> **Publisher:** CED Clinic (https://cedclinic.com)
> **Canonical URL:** https://cedclinic.com/research/visual-function-use-randomized-controlled-trial/
> **Published:** 2026-10-24T12:00:18-04:00 | **Last Modified / Clinically Audited:** 2026-10-24T12:00:18-04:00
> **Clinical Summary:** Thirty young adults who sometimes use cannabidiol, a non-intoxicating part of the cannabis plant, took part in this study.

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Purpose: To study the influence of different concentrations of vaporized cannabidiol (CBD; 0%, 15%, and 30%) on visual function and optical quality. Methods: A randomized, crossover, double-blind, placebo-controlled, experimental study was conducted. A total of 30 participants with a mean age of 26.0 ± 6.3 years completed the study. Placebo (0 mg of CBD), 15% (16 mg of CBD), and 30% (32 mg of CBD) concentrations of CBD were employed. Visual function was evaluated through various tests, including pupil size, static and dynamic visual acuity, contrast sensitivity, dot motion detection, visual disturbance index (VDI), and stereoacuity. Optical quality was assessed by log(s), modulation transfer function (MTF) cutoff, objective scattering index (OSI), and Strehl ratio. Self-perceived visual effects were also recorded. Results: There was no significant impairment of static and dynamic visual acuity. Contrast sensitivity was unaffected by CBD use. Mean dot motion detection showed no differences among the three concentrations. In optical quality, none of the parameters worsened under CBD use. No changes were observed for the VDI. In addition, no deterioration was observed for stereoacuity at distance or near. No changes in pupil size were found after CBD consumption. Conclusions: This non-psychotropic CBD did not appear to adversely affect vision and seems to be a safe substance in the short term at the concentrations assessed. Translational Relevance: The use of this cannabinoid would not be dangerous for tasks that rely heavily on vision. This study could be useful and helpful for evidence-based decision-making for public health policy on its use.

 

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### Verification & Medical Governance

- **Lead Clinical Author:** Benjamin Caplan, MD
- **Credentials:** Board Certified in Family Medicine (ABFM), Founder & CMO CED Clinic & CED Foundation, Author of *The Doctor-Approved Cannabis Handbook* (Penguin Random House).
- **Clinical Scale:** 350,000+ lifetime evaluations overseen; 81,008-patient Real-World Evidence Registry (`~/.ced_rwe_vault.db`); 125,000+ peer-reviewed study literature observatory (`http://localhost:8768/api/explorer/terminal`).
- **License Verification:** Commonwealth of Massachusetts License #240562 (https://checkahealthlicense.mass.gov/).
- **NPI Registry:** 1962722637 (https://npiregistry.cms.hhs.gov/provider-view/1962722637).
- **Ethics & Data Privacy:** Clinical registry observations adhere strictly to HIPAA Safe Harbor de-identification (45 CFR § 164.514(b)) and criteria for secondary research exemption under 45 CFR § 46.104(d)(4).