title: Validation of Concentric Rings Method as a Topographic Measure of Retinal Nonperfusion in Ultra-Widefield Fluorescein Angiography.
abstract: OBJECTIVE
  To validate the use of concentric rings as a method to measure topographic area of retinal nonperfusion in ultra-widefield angiography with the ischemic index method, which is the most frequently used method to measure nonperfusion in ultra-widefield angiography.
  
  
  METHODS
  Validation study and reliability analysis.
  
  
  METHODS
  setting: Single-center study performed at National Institute for Health Research Moorfields Biomedical Research Centre, London, United Kingdom.
  
  
  METHODS
  Twenty-eight ultra-widefield angiogram images of eyes with central retinal vein occlusion.
  
  
  METHODS
  The concentric rings method consists of 6 macula-centered concentric rings divided into 12 segments each. Each image was graded by 5 graders using both the concentric rings and the ischemic index methods.
  
  
  METHODS
  Agreement between the 2 methods was calculated using the intraclass correlation coefficient. Intertest agreement, intergrader agreement, test-retest reliability, and the time taken to grade using these 2 methods were compared.
  
  
  RESULTS
  The intertest agreement between concentric rings method and ischemic index method was 0.965. The intergrader agreement was 0.910 for the concentric rings method and 0.898 with the ischemic index method. The test-retest reliability was 0.975 for the rings and 0.979 for the ischemic index. Average grading time per image was 187 s and 297 s for the concentric rings method and ischemic index method, respectively, P < .001.
  
  
  CONCLUSIONS
  The concentric rings method has an "almost-perfect" intergrader agreement and intertest agreement with the ischemic index method, with a shorter grading time.
authors.affiliation: National Institute for Health Research Moorfields Biomedical Research Centre and University College London Institute of Ophthalmology, London, United Kingdom.
authors.forename: Luke
authors.initials: L
authors.lastname: Nicholson
authors.affiliation: National Institute for Health Research Moorfields Biomedical Research Centre and University College London Institute of Ophthalmology, London, United Kingdom.
authors.forename: Clara
authors.initials: C
authors.lastname: Vazquez-Alfageme
authors.affiliation: National Institute for Health Research Moorfields Biomedical Research Centre and University College London Institute of Ophthalmology, London, United Kingdom.
authors.forename: Jayashree
authors.initials: J
authors.lastname: Ramu
authors.affiliation: National Institute for Health Research Moorfields Biomedical Research Centre and University College London Institute of Ophthalmology, London, United Kingdom.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Triantafyllopoulou
authors.affiliation: National Institute for Health Research Moorfields Biomedical Research Centre and University College London Institute of Ophthalmology, London, United Kingdom.
authors.forename: Namritha V
authors.initials: NV
authors.lastname: Patrao
authors.affiliation: National Institute for Health Research Moorfields Biomedical Research Centre and University College London Institute of Ophthalmology, London, United Kingdom.
authors.forename: Mahdi
authors.initials: M
authors.lastname: Muwas
authors.affiliation: National Institute for Health Research Moorfields Biomedical Research Centre and University College London Institute of Ophthalmology, London, United Kingdom.
authors.forename: Farrah
authors.initials: F
authors.lastname: Islam
authors.affiliation: National Institute for Health Research Moorfields Biomedical Research Centre and University College London Institute of Ophthalmology, London, United Kingdom.
authors.forename: Philip G
authors.initials: PG
authors.lastname: Hykin
authors.affiliation: National Institute for Health Research Moorfields Biomedical Research Centre and University College London Institute of Ophthalmology, London, United Kingdom; King's College Hospital National Health Service Foundation Trust, London, United Kingdom. Electronic address: senswathi@aol.com.
authors.forename: Sobha
authors.initials: S
authors.lastname: Sivaprasad
mesh_terms: D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D012372:ROC Curve; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology*; D012170:Retinal Vein Occlusion / Q000175:diagnosis*; D012171:Retinal Vessels / Q000473:pathology