Alterations of the tear film and ocular surface health in chronic smokers

Objective To investigate the effects of chronic smoking on ocular surface and tear functions. Methods Fifteen right eyes of 15 healthy chronic smokers (9 men, 6 women; age range: 36-47 years) who smoked 20 cigarettes per day for 20 years and 20 eyes of 20 control nonsmokers (12 men, 8 women; age range: 38-43 years) were included in this prospective study. All subjects underwent measurements of breath and haemoglobin CO concentration, tear lipid layer interferometry, evaporimetry, tear film break-up time (TBUT), Schirmer's I test, corneal fluorescein staining, conjunctival impression, and brush cytology. Results The mean Hb CO level was significantly higher in smokers compared to non-smokers. TBUT was also significantly shorter in smokers. Tear lipid layer showed significant slowing in spread over the tear film with a concomitant significant increase in tear evaporation rate. Conjunctival impression cytology revealed significant loss of goblet cells and squamous metaplasia in smokers. Brush cytology showed significant conjunctival neutrophil infiltration in smoker subjects. Conclusion Chronic smoking induced distinctive quantitative and qualitative disturbances on the ocular surface health.