title: The effects of chronic smoking on the ocular surface and tear characteristics: a clinical, histological and biochemical study.
abstract: OBJECTIVE
  To investigate the effects of chronic smoking on the ocular surface and tear characteristics.
  
  
  METHODS
  The Schirmer I-test, tear film break-up time, rose Bengal staining scores, impression cytology, tear lysozyme concentration, eye irritation symptoms, and eye irritation indices were determined for 44 eyes in 44 healthy, chronic smokers who had smoked six or more cigarettes per day for the previous year. Thirty-seven eyes in 37 healthy, non-smokers were assessed in the same masked manner for comparison. Cytological specimens were obtained from the temporal interpalpebral bulbar conjunctiva by 'impression' technique. Goblet cells were counted in the specimens obtained and squamous metaplasia was graded following epithelial cell morphology assessment.
  
  
  RESULTS
  In chronic smokers, we found decreased tear film break-up time (p=0.022) and tear lysozyme concentration (p=0.013), and increased Schirmer I-test values (p=0.047), squamous metaplasia scores (p=0.016), eye irritation scores (p<0.001) and eye irritation indices (p=0.013), as compared with the control group. There were no statistically significant differences in goblet cell counts (p=0.710) or rose Bengal staining scores (p=0.827).
  
  
  CONCLUSIONS
  These findings suggest that chronic smoking has a negative effect on the ocular surface and affects some tear characteristics. The chronic ocular irritative effects of cigarette smoking may lead to defects in ocular surface defence.
authors.affiliation: Department of Ophthalmology, Harran University Medical School, Sanliurfa, Turkey. asatici1@superonline.com
authors.forename: Ahmet
authors.initials: A
authors.lastname: Satici
authors.forename: Muharrem
authors.initials: M
authors.lastname: Bitiren
authors.forename: Ilyas
authors.initials: I
authors.lastname: Ozardali
authors.forename: Huseyin
authors.initials: H
authors.lastname: Vural
authors.forename: Adil
authors.initials: A
authors.lastname: Kilic
authors.forename: Mustafa
authors.initials: M
authors.lastname: Guzey
mesh_terms: D000328:Adult; D002452:Cell Count; D002908:Chronic Disease; D003229:Conjunctival Diseases / Q000209:etiology* / Q000378:metabolism; D003316:Corneal Diseases / Q000209:etiology* / Q000378:metabolism; D004847:Epithelial Cells / Q000473:pathology*; D005456:Fluorescent Dyes; D020397:Goblet Cells / Q000473:pathology; D006801:Humans; D008679:Metaplasia; D009113:Muramidase / Q000378:metabolism; D012395:Rose Bengal; D012907:Smoking / Q000009:adverse effects*; D013194:Staining and Labeling / Q000379:methods; D013666:Tears / Q000378:metabolism*
chemical_list: D005456:Fluorescent Dyes; D012395:Rose Bengal; D009113:Muramidase