Effect of Smoking on Retinal Vessel Morphology and Functionality

IRCCS San Raffaele40 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Smokers

Interventions

Eligibility

Sex: ALLMin age: 18 YearsMax age: 99 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

Central Retinal Artery Equivalent (CRAE)

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.

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

Arterial Dilation Percentage Post-Flicker Stimulation

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.