title: Smoking associated with damage to the lipid layer of the ocular surface.
abstract: OBJECTIVE
  To evaluate the effects of smoking on ocular surface.
  
  
  METHODS
  Prospective, comparative, interventional case series.
  
  
  METHODS
  setting: Institutional. study population: Sixty smokers (33 men, 27 women) and 34 healthy subjects (18 men, 16 women) were enrolled into this study. Patients with associated ophthalmic or systemic diseases, and history of contact lens use and ocular surgery were excluded. The duration of average smoking was 13.1 years (range 5 to 35 years).
  
  
  METHODS
  Ocular surface was evaluated by measuring corneal and conjunctival sensitivity, surface staining with fluorescein, tear film breakup time, Schirmer 1 test, and conjunctival impression cytology. Dry eye symptoms were scored by questionnaire. Kinetic analysis of sequential tear interference images obtained by a DR-1 tear lipid layer interferometry was used to investigate the precorneal lipid layer spread. Results were compared with a control group.
  
  
  METHODS
  Comparison of subjective complaints with objective parameters in cigarette smokers and normal subjects.
  
  
  RESULTS
  In the smoker group, the mean Schirmer 1 test value was 10.8 mm (range 8 to 14 mm). The mean breakup time was 5.3 seconds (range 1 to 10 seconds), the average conjunctival sensitivity was 26.2 mm (range 0 to 45 mm), and the average central corneal sensitivity was 37.6 mm (range 5 to 60 mm). There was no statistically significant difference in goblet cell densities or in Schirmer 1 test values between smokers and controls (P > .05). Higher grades of lipid layer changes were observed in smokers by DR-1 interferometry kinetic analysis.
  
  
  CONCLUSIONS
  Smoking has deteriorating effects on the lipid layer of precorneal tear film.
authors.affiliation: Department of Ophthalmology, School of Medicine, Baskent University, Ankara, Turkey. dilek.dursun@gmail.com
authors.forename: Dilek Dursun
authors.initials: DD
authors.lastname: Altinors
authors.forename: Sezin
authors.initials: S
authors.lastname: Akça
authors.forename: Yonca A
authors.initials: YA
authors.lastname: Akova
authors.forename: Banu
authors.initials: B
authors.lastname: Bilezikçi
authors.forename: Eiki
authors.initials: E
authors.lastname: Goto
authors.forename: Murat
authors.initials: M
authors.lastname: Dogru
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tsubota
mesh_terms: D000328:Adult; D000368:Aged; D002452:Cell Count; D003228:Conjunctiva / Q000473:pathology; D003315:Cornea / Q000378:metabolism*; D015352:Dry Eye Syndromes / Q000209:etiology* / Q000378:metabolism; D005260:Female; D020397:Goblet Cells / Q000473:pathology; D006801:Humans; D007368:Interferometry; D050356:Lipid Metabolism / Q000187:drug effects*; D015227:Lipid Peroxidation; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012907:Smoking / Q000009:adverse effects*; D011795:Surveys and Questionnaires; D013666:Tears / Q000378:metabolism