title: Twice-daily use of a chlorobutanol-preserved artificial tear on rabbit corneal epithelium assessed by scanning electron microscopy.
abstract: Female pigmented rabbits received two drops of a chlorobutanol 0.5%-preserved, polyvinyl alcohol-based artificial tear at 21.00 h and 09.00 h for 1, 2, 3, 6 or 12 consecutive days. The animals were killed at 15.00, 6 h after the last treatment. Scanning electron microscopy of the corneal epithelial surface at x 200 magnification revealed only occasional cell exfoliation averaging < 8% of the surface analysed at central, mid-peripheral and peripheral sites, showing minimal cytotoxic effects. The level of exfoliation was maximal after 2 to 3 days treatment and then returned to close to zero, so the eye adapts to repeated use of the artificial tears. Evaluation of the surface microplicae of the cells at x 15,000 indicated subtle, but distinct, changes in what might be the mucus material associated with the cell surface, especially after 2 and 3 days treatment.
authors.affiliation: School of Optometry, University of Waterloo, Ontario, Canada.
authors.forename: M J
authors.initials: MJ
authors.lastname: Doughty
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D002724:Chlorobutanol / Q000633:toxicity*; D003315:Cornea / Q000187:drug effects* / Q000648:ultrastructure; D004305:Dose-Response Relationship, Drug; D004848:Epithelium / Q000648:ultrastructure; D005260:Female; D008855:Microscopy, Electron, Scanning; D009883:Ophthalmic Solutions / Q000633:toxicity*; D011310:Preservatives, Pharmaceutical / Q000633:toxicity; D011817:Rabbits
chemical_list: D009883:Ophthalmic Solutions; D011310:Preservatives, Pharmaceutical; D002724:Chlorobutanol