title: Consistency of ocular coherence tomography fast macular thickness mapping in diabetic diffuse macular edema.
abstract: OBJECTIVE
  To investigate optical coherence tomography consistency on foveal thickness, foveal volume, and macular volume measurements in patients with and without diffuse diabetic macular edema.
  
  
  BACKGROUND
  Optical coherence tomography represents an objective technique that provides cross-sectional tomographs of retinal structure in vivo. However, it is expected that poor fixation ability, as seen in diabetic macular edema, could alter its results. Several authors have discussed the reproducibility of optical coherence tomography, but only a few have addressed the topic with respect to diabetic maculopathy.
  
  
  METHODS
  The study recruited diabetic patients without clinically evident retinopathy (control group) and with diffuse macular edema (case group). Only one eye of each patient was evaluated. Five consecutive fast macular scans were taken using Ocular Coherence Tomography 3; the 6 mm macular map was chosen. The consistency in measurements of foveal thickness, foveal volume, and total macular volume for both groups was evaluated using the Pearson's coefficient of variation. The T-test for independent samples was used in order to compare measurements of both groups.
  
  
  RESULTS
  Each group consisted of 20 patients. All measurements had a coefficient of variation less than 10%. The most consistent parameter for both groups was the total macular volume.
  
  
  CONCLUSIONS
  Consistency in measurement is a mainstay of any test. A test is unreliable if its measurements can not be correctly repeated. We found a good index of consistency, even considering patients with an unstable gaze.
  
  
  CONCLUSIONS
  Optical coherence tomography is a consistent method for diabetic subjects with diffuse macular edema.
authors.affiliation: Departament of Ophthalmology, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil. fabiopetersen@yahoo.com.br
authors.forename: Fábio Petersen
authors.initials: FP
authors.lastname: Saraiva
authors.forename: Patricia Grativol
authors.initials: PG
authors.lastname: Costa
authors.forename: Daniela Lumi
authors.initials: DL
authors.lastname: Inomata
authors.forename: Carlos Sérgio Nascimento
authors.initials: CS
authors.lastname: Melo
authors.forename: John
authors.initials: J
authors.lastname: Helal Júnior
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Nakashima
mesh_terms: D016022:Case-Control Studies; D003930:Diabetic Retinopathy / Q000175:diagnosis*; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D005584:Fovea Centralis / Q000473:pathology; D006801:Humans; D008266:Macula Lutea / Q000473:pathology*; D008269:Macular Edema / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000379:methods*