title: A pilot study using ROPtool to measure retinal vascular dilation.
abstract: BACKGROUND
  Plus disease is abnormal retinal vascular dilation and tortuosity, and it is now the primary indication for laser treatment in retinopathy of prematurity (ROP). ROPtool is a computer program that measures retinal arteriolar tortuosity. Our aim was to assess the accuracy of ROPtool's newly developed measurement of retinal vascular width (dilation).
  
  
  METHODS
  ROPtool was used to measure the width of 154 blood vessels in 20 high-quality RetCam images from 20 premature infants. ROPtool's accuracy was determined by comparing results with the mean grades of 2 authors who scored retinal vascular dilation using a 10-point scale.
  
  
  RESULTS
  There was very good correlation (r = 0.80) between ROPtool's measurement of retinal vascular dilation and author judgment. Areas under receiver operating characteristics curves for identification of dilation sufficient for plus disease and for pre-plus disease were 0.93 and 0.90, respectively. At an optimal point on the receiver operating characteristics curve, ROPtool's sensitivity for diagnosing dilation sufficient for plus disease was 89% (24/27), and its specificity was 83% (106/127).
  
  
  CONCLUSIONS
  In addition to measuring retinal vascular tortuosity, ROPtool now accurately measures retinal vascular width in high-quality RetCam images. Application of this technology has the potential to remove subjectivity from the assessment of plus disease.
authors.affiliation: Department of Ophthalmology, Duke University, Durham, North Carolina, USA. david.wallace@duke.edu
authors.forename: David K
authors.initials: DK
authors.lastname: Wallace
authors.forename: Sharon F
authors.initials: SF
authors.lastname: Freedman
authors.forename: Zheen
authors.initials: Z
authors.lastname: Zhao
mesh_terms: D003936:Diagnosis, Computer-Assisted; D004108:Dilatation, Pathologic / Q000473:pathology; D006801:Humans; D007231:Infant, Newborn; D010865:Pilot Projects; D012372:ROC Curve; D012171:Retinal Vessels / Q000473:pathology*; D012178:Retinopathy of Prematurity / Q000473:pathology*; D012680:Sensitivity and Specificity; D012984:Software