The effect of smoking on ocular surface and tear film based on clinical examination and optical coherence tomography

Purpose: Smoking is a global health problem with a high burden of smokers in India and the world as well. Smoking is a known eye irritant that may have a significant effect on the anterior ocular surface. Hence, the present study was aimed to investigate the effect of smoking on dry eye parameters, ocular surface, and central corneal thickness (CCT) and to compare the results with nonsmokers. Methods: In this cross-sectional study, 40 (80 eyes) smokers and 40 (80 eyes) age-matched nonsmokers were included. The severity of ocular surface disease symptoms was assessed by the Ocular Surface Disease Index (OSDI) tool. All participants underwent a series of measurements, that is, the Schirmer's II test score and tear breakup time (TBUT). Tear meniscus height (TMH) and CCT were measured using anterior segment optical coherence tomography (OCT). Results: The mean value of all dry eye parameters was statistically different among the group of smokers and nonsmokers. The mean score of symptomatic assessment (OSDI) was observed to be significantly higher in smokers than in nonsmokers (P < 0.0001), and dry eye parameters, that is, Schirmer's score (P = 0.0127), TMH (P < 0.0001), and TBUT (P < 0.0001) were significantly lower among smokers than nonsmokers. There was no significant difference in CCT between smokers and nonsmokers (P = 0.06). Conclusion: Cigarette smoking has deteriorating effects on the ocular surface. Exposure to smoking was found to be associated with dryness of the eye. Further studies are needed on a molecular basis.