Effect of Smoking on Retinal Vessel Morphology and Functionality

The study aims at evaluating the effect of smoking activity on anatomy and functionality of retinal blood vessels using optical coherence tomography angiography (OCT-A) and dynamic vessel analysis (DVA).

This is a low-risk, single-center, case-control, interventional clinical trial. Forty healthy subjects were enrolled: 20 healthy volunteers with regular daily tobacco activity (approximately 10 cigarettes per day for 5-10 years) and 20 healthy volunteers with no tobacco activity as controls.

Each subject underwent comprehensive ophthalmologic examination including OCT-A, DVA, and retinal vessel analysis (RVA) at baseline. Examinations were repeated for the smoking group at 3 and 30 minutes after smoking activity, and for controls at 8 and 35 minutes after baseline to assess examination variability.

The primary outcomes assessed changes in retinal perfusion and retinal vascular response after cigarette smoking compared to controls.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Smokers

Age range

18 year–99 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Università Vita Salute San Raffaele

Milan, Italy

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Adults of both sexes (age 20 to 30 years old)
Healthy volunteers who can understand and sign informed consent
For Smokers Group: Regular daily tobacco activity (approximately 10 cigarettes per day, smoking duration 5-10 years, using cigarettes with 0.8 grams nicotine content)
For Control Group: No tobacco activity as normal life habit
Willing to abstain from tobacco activity for 24 hours prior to baseline examination
Willing to avoid vasoconstrictor substances (coffee, alcohol) prior to examinations

Exclusion criteria

Inability to follow planned procedures
Opacity of dioptric media (lens, cornea, or vitreous) that prevents execution of examinations
Known allergies that do not allow pupillary dilation
Ocular pathologies
Systemic hypertension
Diabetes mellitus
Myopia greater than -8.0 Diopters (D)
Hyperopia greater than +5.0 D
Astigmatism greater than -3.0 D

Treatment and study plan

Cigarette Smoking

Behavioral

Participants smoked one cigarette containing 0.8 grams of nicotine under standardized conditions. Participants were required to abstain from tobacco activity for 24 hours prior to baseline examination and to avoid vasoconstrictor substances (coffee, alcohol) before examinations.

Primary outcomes

Central Retinal Artery Equivalent (CRAE)

Time frame: Baseline, 3 minutes and 30 minutes post-smoking (smokers); baseline, 8 minutes and 35 minutes (controls)

Changes in central retinal artery equivalent measured using Retinal Vessel Analyzer (RVA). CRAE relates to the diameter of the central retinal artery, expressed in measurement units (MU). Higher values indicate larger arterial diameter.
Arterial Dilation Percentage Post-Flicker Stimulation

Time frame: Baseline, 3 minutes and 30 minutes post-smoking (smokers); baseline, 8 minutes and 35 minutes (controls)

Percentage increase in retinal arterial vessel diameter in response to flicker light stimulation measured by Dynamic Vessel Analyzer (DVA). Calculated as percentage increase in vessel diameter relative to baseline after 20 seconds of flicker stimulation, averaged across 3 measurement cycles.

Sponsors and collaborators

Lead sponsor

IRCCS San Raffaele

Other

Registry information

Official study title

Effect of Smoking on Retinal Vessel Morphology and Functionality: A Case-Control, Clinical Trial

Important dates

Study start: 2021
Primary completion: 2024
Study completion: 2024
First posted: Dec 3, 2025
Registry last updated: Dec 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

Completed