title: The effect of smoking on the ocular surface and the precorneal tear film.
abstract: BACKGROUND
  Smoking, both active and passive, creates a plethora of health-related problems, which primarily affect the cardiovascular and respiratory systems. There is very little evidence on the effects of tobacco smoke on the eye, especially regarding anterior ocular surface related pathology. This study was undertaken to determine the effects of smoking on the ocular surface and the tear film in smokers.
  
  
  METHODS
  A total of 51 (102 eyes) smokers and 50 (100 eyes) age-and gender-matched healthy non-smokers were included in this study. The ocular surface was evaluated by measuring tear film break-up time, surface staining with fluorescein, and corneal and conjunctival sensitivities, and by completing the Schirmer's II test. Data was analysed using Statistical Package for Social Sciences (SPSS) version 11.5. A p value less than 0.05 was considered statistically significant.
  
  
  RESULTS
  The smoker group had significantly lower tear film break-up time, and corneal and conjunctival sensitivity than the nonsmoker group. Punctate staining was significantly higher in the smoker group than the non-smoker group. There was no statistically significant difference in Schirmer's II test results between the smoker and non-smoker group.
  
  
  CONCLUSIONS
  Smoking caused adverse effects on the precorneal tear film and there was strong association between smoking and tear film instability. Although a causative relationship could not be determined, there is a need for further longitudinal studies.
authors: Manipal College of Allied Health Sciences, Manipal University, Manipal, India.
authors: Jyothi
authors: J
authors: Thomas
authors: George P
authors: GP
authors: Jacob
authors: Lekha
authors: L
authors: Abraham
authors: Babu
authors: B
authors: Noushad