The study suggests that antioxidant and lipid-based eye drops may offer a more sustainable therapy by directly reducing oxidative damage to the meibum caused by smoking.
A new cross-sectional study, published in Frontiers in Medicine by Ting Chen and colleagues from the Department of Ophthalmology at Shanxi Cardiovascular Hospital in Taiyuan, China, sheds light on how chronic smoking affects the structure and function of the meibomian glands—oil-producing glands essential for maintaining tear film stability. The research provides compelling evidence that smoking exposure is closely linked to progressive gland damage and worsening ocular surface health.
The study evaluated 104 long-term smokers, each with a smoking history exceeding five years, alongside 44 non-smokers. Participants were grouped into non-smoking, mild, moderate, and heavy smoking categories based on their smoking index. Using detailed imaging, the team assessed multiple gland features, including dropout area, gland number, height, and width. Additional examinations of eyelid margin appearance, meibum quality, secretion levels, and tear film breakup time (TBUT) offered a comprehensive view of how smoking influences both the structure and function of the glands.
The findings were striking:
- Meibomian gland dropout area showed a strong positive correlation with smoking exposure (β = 0.449).
- Increasing smoking index was associated with a reduction in the number, height, and width of the meibomian glands, indicating progressive structural damage.
- Eyelid margin abnormalities increased with higher smoking levels, demonstrating worsening morphological changes.
- Meibum secretion quality and quantity deteriorated with greater smoking exposure, pointing to significant functional impairment.
- Tear film stability declined notably, with a negative correlation observed between TBUT and smoking index (β = −0.245).
According to the authors, the destructive effects observed in the study are likely driven by tobacco-induced oxidative stress and persistent inflammation. These mechanisms not only disrupt meibum production but also contribute to squamous metaplasia and other pathological changes that characterize meibomian gland dysfunction (MGD).
MGD treatments like artificial tears, warm compresses, and gland massage offer only short-term relief and do not address smoking-related gland damage. The study stresses the need for targeted therapies, noting that antioxidant and lipid-based eye drops may better counteract tobacco-induced oxidative injury. Smoking cessation, avoiding secondhand smoke, and careful use of anti-inflammatory medications remain essential.
The authors also highlight that meibomian glands are sensitive to environmental pollutants. Beyond cigarettes, wildfire smoke, traffic emissions, industrial pollutants, biomass fuel, and e-cigarette aerosols may cause similar damage. They call for further research and stronger collaboration between eye specialists and environmental health experts.
"The work reinforces a critical message: smoking harms not only the lungs and heart but also the eyes, with effects that can progressively erode tear film health and overall visual comfort," they concluded.
Chen, T., Wang, R., Liang, S., & Feng, J. (2025). Impact of smoking exposure on meibomian gland morphology and tear film stability: A cross-sectional study. Frontiers in Medicine, 12, 1711567. https://doi.org/10.3389/fmed.2025.1711567
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