title: Corneal epithelial permeability of dry eyes before and after treatment with artificial tears.
abstract: OBJECTIVE
  The question of whether artificial tears can lead to objective improvement of ocular surface disease in dry eyes is still unanswered. The aim of the current study is to assess the influence of artificial tears on corneal epithelial permeability of dry eyes. Furthermore, the effect of benzalkonium chloride, used as a preservative of artificial tears, on corneal epithelial permeability is investigated.
  
  
  METHODS
  The corneal epithelial permeability of 40 dry eye patients (80 eyes) was measured by computerized objective fluorophotometry before and 6 weeks after treatment with artificial tears containing either polyvinyl pyrrolidone 2% without preservative (20 patients) or polyvinyl pyrrolidone 2% preserved with benzalkonium chloride 0.005% (20 patients).
  
  
  RESULTS
  Before treatment, the epithelial permeability of the dry eye patients was found to be 2.7 times that of a control group. After treatment, the epithelial permeability of patients treated with unpreserved polyvinyl pyrrolidone 2% had decreased significantly (-37%; P less than 0.001), whereas patients who had been treated with polyvinyl pyrrolidone 2% preserved with benzalkonium chloride 0.005% showed an increase in epithelial permeability (+21%; P = 0.05%).
  
  
  CONCLUSIONS
  These data suggest that, in dry eyes, treatment with unpreserved artificial tears may lead to an objective improvement in corneal surface disease. However, this effect may be counteracted by preservation of tear substitutes with benzalkonium chloride.
authors.affiliation: University Eye Hospital, Bonn, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Göbbels
authors.forename: M
authors.initials: M
authors.lastname: Spitznas
mesh_terms: D001548:Benzalkonium Compounds / Q000493:pharmacokinetics; D003315:Cornea / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism; D015352:Dry Eye Syndromes / Q000188:drug therapy*; D004848:Epithelium / Q000378:metabolism; D019793:Fluorescein; D005452:Fluoresceins / Q000378:metabolism; D015590:Fluorophotometry; D006801:Humans; D008875:Middle Aged; D010539:Permeability; D011206:Povidone-Iodine / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D001548:Benzalkonium Compounds; D005452:Fluoresceins; D011206:Povidone-Iodine; D019793:Fluorescein