title: Simplified correction of ischemic index in diabetic retinopathy evaluated by ultra-widefield fluorescein angiography.
abstract: OBJECTIVE
  To develop a novel, simplified method for correcting the ischemic index of nonperfused areas in diabetic retinopathy (DR).
  
  
  METHODS
  We performed a retrospective review of 103 eyes with naive DR that underwent ultra-widefield angiography (UWFA) over a year. UWFAs were graded according to the quantity of retinal non-perfusion, and uncorrected ischemic index (UII) and corrected ischemic index (CII) were calculated using a simplified, novel method.
  
  
  RESULTS
  The average differences between UII and CII in the non-proliferative DR group and the proliferative DR group were 0.7 ± 0.9% in the <25% CII group, 3.0 ± 0.9% in the 25% to 49.9% CII group, and 3.6 ± 0.6% in the >50% CII group, respectively. A CII >25% was critical for determining DR progression (p < 0.001).
  
  
  CONCLUSIONS
  Distortion created by UWFA needs to be corrected because the difference between UII and CII in DR increases with the ischemic index.
authors.affiliation: HanGil Eye Hospital, Incheon, Korea.
authors.forename: Jeong Hee
authors.initials: JH
authors.lastname: Kim
authors.affiliation: HanGil Eye Hospital, Incheon, Korea.
authors.forename: Hyeong-Gi
authors.initials: HG
authors.lastname: Jung
authors.affiliation: HanGil Eye Hospital, Incheon, Korea.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Chung
authors.affiliation: HanGil Eye Hospital, Incheon, Korea.
authors.forename: Kyungmin
authors.initials: K
authors.lastname: Lee
authors.affiliation: HanGil Eye Hospital, Incheon, Korea.
authors.forename: Joonhong
authors.initials: J
authors.lastname: Sohn
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D006801:Humans; D007511:Ischemia / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012169:Retinal Vein / Q000473:pathology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: Diabetic retinopathy; Ischemic index; Wide-field fluorescein angiography