title: Repeatability of infrared ocular thermography in assessing healthy and dry eyes.
abstract: OBJECTIVE
  To investigate the inter-image, inter-occasion and inter-examiner repeatability of NEC infrared thermo-tracer TH 9260 in assessing healthy and dry eyes.
  
  
  METHODS
  Ocular surface temperature (OST) was recorded using NEC infrared thermo-tracer TH 9260 on 21 healthy and 15 dry eyes. Data from the right eyes were analyzed. Marking of the ocular surface and OST acquisition was performed using a new 'diamond' demarcation method. Twelve OST indices were obtained at three different time points following a blink: 0s, 5s and 10s. Inter-image, inter-occasion and inter-examiner repeatability of the infrared ocular thermography was evaluated by calculating coefficients of repeatability (COR).
  
  
  RESULTS
  Ten out of the twelve tested OST indices had good repeatability with small inter-image variability (%COR: 0.2-0.9), inter-occasion variability (%COR: 2.1-3.7) and inter-examiner variability (%COR: 1.5-3.7) for the three studied time points. Two of the OST indices (temperature standard deviation of the region of interest and radial temperature difference) had poor repeatability with much larger inter-image variability (%COR: 8.9-140.7), inter-occasion variability (%COR: 47.5-153.5) and inter-examiner variability (%COR: 54.7-142.0) for the three studied time points.
  
  
  CONCLUSIONS
  Most of the metrics adopted in this assessment can be considered to be highly repeatable.
authors.affiliation: School of Chemical and Life Sciences, Singapore Polytechnic, Singapore. Electronic address: tanlili@sp.edu.sg.
authors.forename: Li Li
authors.initials: LL
authors.lastname: Tan
authors.affiliation: Ophthalmology and Visual Sciences, Khoo Teck Puat Hospital, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Sanjay
authors.affiliation: Eurolens Research, The University of Manchester, UK.
authors.forename: Philip B
authors.initials: PB
authors.lastname: Morgan
mesh_terms: D001831:Body Temperature; D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation*; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D015352:Dry Eye Syndromes / Q000175:diagnosis* / Q000503:physiopathology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007259:Infrared Rays; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012881:Skin Temperature; D013817:Thermography / Q000295:instrumentation*
keywords: Dry eye; Infrared ocular thermography; Ocular surface temperature; Repeatability