title: Tear film instability induced by rigid contact lenses.
abstract: OBJECTIVE
  To evaluate rigid contact lens-associated epithelial damage, the relationship between the tear film and the ocular surface epithelium was evaluated at the perilimbal area around rigid contact lenses (RCLs).
  
  
  METHODS
  Twenty RCL [six polymethylmethacrylate (PMMA) and 14 rigid gas-permeable lens (RGPL)] wearers and 20 non-CL wearers were enrolled in this study. By using a newly developed tear interferometer, the noninvasive tear film break-up time (NIBUT) on the conjunctiva at the 3- and 9-o'clock portions was measured, and its stability evaluated. Fluorescein and sulforhodamine B staining was used to observe ocular-surface epithelial damage, and rose bengal staining was used to evaluate the mucin layer distribution.
  
  
  RESULTS
  The conjunctival NIBUT at the 3- or 9-o'clock portions or both was abnormally shortened in 15 (75%) of 20 RCL-wearer eyes. Conjunctival epithelial staining at the 3- or 9-o'clock portion was seen in six (30%) of 20 eyes by using sulforhodamine B, and in four (20%) of 20 eyes by rose bengal; all of these eyes also demonstrated an abnormal tear film breakup. Corneal epithelial damage was seen in two (10%) of 20 RCL-wearer eyes at the 3- or 9-o'clock portions or both, and in both of these cases, conjunctival epithelial damage also was noted. Neither tear-film instability nor epithelial staining was seen in the normal controls.
  
  
  CONCLUSIONS
  This study indicates that RCL-induced tear-film instability is associated with damage to the ocular-surface epithelium and mucin layer.
authors.affiliation: Department of Ophthalmology, Kyoto Prefectural University of Medicine, Japan. ritoh@eye.ophth.kpu-m.ac.jp
authors.forename: R
authors.initials: R
authors.lastname: Itoh
authors.forename: N
authors.initials: N
authors.lastname: Yokoi
authors.forename: S
authors.initials: S
authors.lastname: Kinoshita
mesh_terms: D000328:Adult; D002452:Cell Count; D003229:Conjunctival Diseases / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D003261:Contact Lenses / Q000009:adverse effects*; D003316:Corneal Diseases / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D004847:Epithelial Cells / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D012235:Rhodamines; D012395:Rose Bengal; D013666:Tears / Q000378:metabolism*
chemical_list: D012235:Rhodamines; D012395:Rose Bengal; C022027:lissamine rhodamine B