title: Assessment of tear film stability in dry eye with a newly developed keratograph.
abstract: OBJECTIVE
  To investigate the applicability of a newly developed corneal topographer in assessing tear film stability.
  
  
  METHODS
  This is a prospective, case-control study. Forty-four Chinese dry eye patients and 41 normal subjects were recruited. Noninvasive tear film break-up time (NI-BUT) was measured using a new method based on a corneal topographer equipped with modified scan software. The reliability of the measurements was determined. Then, the correlations between the NI-BUT and the traditional fluorescein tear film break-up time, Schirmer I test values, and inferior tear meniscus height measurements were determined. The receiver operating characteristic curve technique was used to evaluate the NI-BUT examination in the diagnosis of dry eye.
  
  
  RESULTS
  In total, a significant difference between the NI-BUT and the fluorescein tear film break-up time was found (3.2 ± 2.3 seconds vs. 5.2 ± 3.4 seconds; P < 0.001). The coefficient of variation and intraclass correlation coefficient values of NI-BUT were 12.8% and 0.93, respectively, for NI-BUT for intraobserver repeatability and 15.4% and 0.88, respectively for interobserver repeatability. The NI-BUT showed a good correlation with other dry eye examinations (all P < 0.05). In addition, the NI-BUT was significantly shorter in dry eye patients (2.0 ± 0.2 seconds) than in normal subjects (4.3 ± 0.3 seconds; P < 0.001). When the cutoff value was set at <2.65 seconds, the sensitivity and specificity of the test were 84.1% and 75.6%, respectively.
  
  
  CONCLUSIONS
  Measurements of NI-BUT obtained with the newly developed corneal topographer may provide a simple, noninvasive screening test for dry eyes with acceptable sensitivity, specificity, and repeatability.
authors.affiliation: Department of Ophthalmology and Visual Science, Eye, Ear, Nose, and Throat Hospital, School of Shanghai Medicine, Fudan University, Shanghai, China.
authors.forename: Jiaxu
authors.initials: J
authors.lastname: Hong
authors.forename: Xinghuai
authors.initials: X
authors.lastname: Sun
authors.forename: Anji
authors.initials: A
authors.lastname: Wei
authors.forename: Xinhan
authors.initials: X
authors.lastname: Cui
authors.forename: Yimin
authors.initials: Y
authors.lastname: Li
authors.forename: Tingting
authors.initials: T
authors.lastname: Qian
authors.forename: Wentao
authors.initials: W
authors.lastname: Wang
authors.forename: Jianjiang
authors.initials: J
authors.lastname: Xu
mesh_terms: D000328:Adult; D019781:Corneal Topography / Q000379:methods*; D015352:Dry Eye Syndromes / Q000175:diagnosis* / Q000378:metabolism; D005260:Female; D015590:Fluorophotometry; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D013666:Tears / Q000502:physiology*