Dry Eye Disease and Retinal Nerve Fiber Layer Thickness in Chronic Smokers

Assessment of Dry Eye Disease and Retinal Nerve Fiber Layer Thickness in Chronic Smokers

This study aimed to examine the impact of long-term smoking on dry eye parameters and retinal nerve fiber layer thickness in individuals who are chronic smokers.

Study Overview

• Status: Completed
• Conditions: Dry Eye Disease; Retinal Nerve Fiber Layer; Chronic Smoking
• Intervention / Treatment: Other: Dry eye assessment

Detailed Description

Dry eye disease (DED) is a multifaceted disorder of the ocular surface characterized by instability of the tear film, which subsequently leads to symptoms such as ocular discomfort, visual disturbances, and potential damage to the surface of the eye.

Cigarette smoking has been recognized as a possible contributing factor to the development of DED, with various reports suggesting that it may alter tear film composition and stability, leading to ocular surface damage.

Chronic smoking can lead to oxidative stress, vascular dysfunction, and inflammation, which may contribute to retinal nerve fiber layer (RNFL) thinning and optic nerve damage.

• Study Type: Observational
• Enrollment (Actual): 50

Contacts and Locations

Study Locations

• Egypt
  • Cairo, Egypt, 12613
    • Cairo University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

This observational case-control study was conducted on a total of 100 eyes from 50 patients.

Description

Inclusion Criteria:

• Age from 30 to 60 years.
• Both sexes.
• Chronic smokers.

Exclusion Criteria:

• History of ocular surface diseases affecting tear production or secretion (such as Sjogren's syndrome or Stevens-Johnson disease).
• Conjunctivitis.
• Blepharitis.
• Chronic contact lens use or gross lid abnormalities.
• Preexisting glaucoma.
• Retinal diseases.
• Optic nerve pathology.
• Ocular trauma.
• Chemical burns.
• Recent eye surgery (within three months).
• Trachoma-related complications

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Group A; Non-smokers.	Other: Dry eye assessment; Dry eye assessment was performed using the Mediworks Dry Eye Diagnostic System.
Group B; Chronic smokers (≥1 pack/day for ≥10 years).	Other: Dry eye assessment; Dry eye assessment was performed using the Mediworks Dry Eye Diagnostic System.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Non-invasive tear film breakup time	Non-invasive tear film breakup time (NIBUT) was automatically analyzed using artificial intelligence, with results classified as Grade 0 (normal, first rupture time >10s), Grade 1 (warning, 6- 9s), or Grade 2 (dry eye, ≤5s)	During examination (Baseline)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Tear meniscus height	Tear meniscus height (TMH) values above 0.2mm were considered healthy, while lipid layer thickness was graded from 1 (<30nm) to 4 (>80nm).	During examination (Baseline)
Lipid layer thickness	Lipid layer thickness was graded from 1 (<30nm) to 4 (>80nm).	During examination (Baseline)
Ocular Surface Disease Index (OSDI) score	The ocular surface disease index (OSDI) score was categorized as normal (≤12), mild (13-22), moderate (23-32), or severe (≥33).	During examination (Baseline)
Retinal nerve fiber layer thickness	Retinal nerve fiber layer (RNFL) thickness was measured using Fourier-domain OCT Optovue RTVue (Optovue Inc., Fremont, CA, USA).	During examination (Baseline)
Correlations between dry eye parameters and Ocular Surface Disease Index (OSDI) score	Correlations between dry eye parameters and Ocular Surface Disease Index (OSDI) score was assessed.	During examination (Baseline)
Correlations between dry eye parameters and retinal nerve fiber layer (RNFL) thickness in both groups	Correlations between dry eye parameters and retinal nerve fiber layer (RNFL) thickness in both groups was assessed.	During examination (Baseline)

Collaborators and Investigators

• Sponsor: Cairo University

Study record dates

Study Major Dates

• Study Start (Actual): May 2, 2023
• Primary Completion (Actual): May 1, 2024
• Study Completion (Actual): May 1, 2024

Study Registration Dates

• First Submitted: June 3, 2025
• First Submitted That Met QC Criteria: June 11, 2025
• First Posted (Actual): June 19, 2025

Study Record Updates

• Last Update Posted (Actual): June 19, 2025
• Last Update Submitted That Met QC Criteria: June 11, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Corneal Diseases; Lacrimal Apparatus Diseases; Keratoconjunctivitis; Conjunctivitis; Conjunctival Diseases; Keratitis; Eye Diseases; Dry Eye Syndromes; Keratoconjunctivitis Sicca
• Other Study ID Numbers: MS-250-2023

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The data will be available upon a reasonable request from the corresponding author after the end of study for one year.
• IPD Sharing Time Frame: After the end of study for one year.
• IPD Sharing Access Criteria: The data will be available upon a reasonable request from the corresponding author.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No