title: Symptoms, visual function, and mucin expression of eyes with tear film instability.
abstract: OBJECTIVE
  We examined symptoms, tear stability, visual function, and conjunctival cytology in eyes with an unstable tear film (UTF), expressed as a short tear film breakup time without epithelial damage or low tear secretion, and compared the results with those from eyes with aqueous deficiency (AD) associated with epithelial damage, and healthy eyes.
  
  
  METHODS
  We divided the patients with ocular discomfort into 2 groups according to the breakup time, Schirmer value, and epithelial staining score: UTF group (≤5 seconds, >5 mm, and <3 points; 21 eyes of 21 patients) and AD group (≤5 seconds, ≤5 mm, and ≥3 points; 21 eyes of 21 patients). We examined all patients and 17 healthy subjects for symptoms, tear functions, tear film stability by tear film lipid layer interferometry and tear film analysis system, and functional visual acuity. Conjunctival impression cytology was performed to investigate changes in goblet cell density, squamous metaplasia, and messenger RNA expression of MUC5AC and MUC16.
  
  
  RESULTS
  The symptom scores, tear film analysis system index, and functional visual acuity testing were significantly worse in the UTF and AD groups compared with those in the control group (P < 0.05). The messenger RNA expression levels of MUC5AC and MUC16 were significantly lower in UTF and AD eyes compared with those in the control eyes (P < 0.0001).
  
  
  CONCLUSIONS
  An UTF itself can cause dry eye symptoms and visual disturbance comparable with those of AD dry eyes.
authors.affiliation: Department of Ophthalmology, Tokyo Dental College, Chiba, Japan. dens@tdc.ac.jp
authors.forename: Seika
authors.initials: S
authors.lastname: Shimazaki-Den
authors.forename: Murat
authors.initials: M
authors.lastname: Dogru
authors.forename: Kazunari
authors.initials: K
authors.lastname: Higa
authors.forename: Jun
authors.initials: J
authors.lastname: Shimazaki
mesh_terms: D018394:CA-125 Antigen / Q000235:genetics*; D002452:Cell Count; D003228:Conjunctiva / Q000473:pathology; D004185:Disability Evaluation; D015352:Dry Eye Syndromes / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D015870:Gene Expression; D020397:Goblet Cells / Q000473:pathology; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D055271:Mucin 5AC / Q000235:genetics*; D011446:Prospective Studies; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D013666:Tears / Q000378:metabolism*; D014792:Visual Acuity / Q000502:physiology*
chemical_list: D018394:CA-125 Antigen; C451759:MUC16 protein, human; C524678:MUC5AC protein, human; D008565:Membrane Proteins; D055271:Mucin 5AC; D012333:RNA, Messenger