An observational study in Smoking ( Cigarette), Cornea and Anterior Eye Segment Measurements, sponsored by Istanbul University. Recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-05-12.
Sponsored by Istanbul University · Observational
This prospective study aims to evaluate the short-term effects of smoking on corneal tomographic and biometric measurements in healthy adults. After baseline examinations and measurements are taken in both smoking and non-smoking participants, the same measurements will be repeated after 10 minutes of external exposure, and within-group and between-group changes will be compared. The aim of the study is to determine whether acute smoking exposure leads to measurable immediate changes in corneal tomographic and biometric parameters.
This study is a single-center, prospective, and controlled study designed to evaluate the short-term effects of smoking on corneal tomographic and biometric measurements in healthy adults. The study aimed to include 46 smokers and 46 non-smokers. To avoid inter-eye correlation, only the right eye of each participant was evaluated. All participants initially underwent a full ophthalmological examination and measurements were taken using a Pentacam device. Afterward, all participants waited in standard outdoor conditions for 10 minutes. During this time, participants in the smoking group smoked, while participants in the control group did not smoke. The same measurements were repeated at the end of the period. The study aimed to compare within-group and between-group differences in changes.
114 studies on the registry are indexed under Cigarette Smoking; 59 are open to participants now.
This study's planned enrollment of 90 is below the median of 123 across 12 observational studies indexed under Cigarette Smoking.
Browse Cigarette Smoking studies →Istanbul University is the lead sponsor of 496 studies on the registry; 79 are open to participants now.
Of its 5 completed or terminated interventional studies of FDA-regulated products, 1 (20%) have results posted.
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Healthy adult smokers and non-smokers aged 18 to 60 years are planned to be included in this single-center study.
Exclusion Criteria:
Healthy adult participants with active cigarette smoking exposure who underwent baseline ophthalmic examination and Pentacam measurements, followed by repeat measurements after a standardized 10-minute outdoor period during which they smoked.
Other: Cigarette Smoking Exposure
Healthy adult participants without cigarette smoking exposure who underwent baseline ophthalmic examination and Pentacam measurements, followed by repeat measurements after a standardized 10-minute outdoor period under the same environmental conditions without smoking.
Other: No Smoking Exposure
Participants in the smoking group smoked cigarettes during a standardized 10-minute outdoor period between baseline and post-exposure assessments.
Participants in the control group remained in the same outdoor environment for 10 minutes without smoking between baseline and post-exposure assessments.
Change in Pentacam-measured corneal pachymetry at the pupil center after acute cigarette smoking exposure
Change (post-exposure minus baseline) in corneal pachymetry at the pupil center, measured in micrometers (µm) using Pentacam. The magnitude of change will be compared between smokers and non-smokers.
Time frame: Baseline and immediately after a standardized 10-minute outdoor exposure period
Change in Pentacam-measured corneal densitometry in the anterior 0-2 mm zone after acute cigarette smoking exposure
Change (post-exposure minus baseline) in corneal densitometry in the anterior 0-2 mm zone, measured in grayscale units (GSU) using Pentacam. The magnitude of change will be compared between smokers and non-smokers.
Time frame: Baseline and immediately after a standardized 10-minute outdoor exposure period
Plan to share: No — Individual participant data will not be shared because the study was not designed with a data-sharing plan and the dataset contains participant-level information.
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