title: The role of a second isolated retinal artery in branch retinal vein obstruction.
abstract: OBJECTIVE
  To evaluate the prevalence of a second isolated retinal artery in eyes with and without branch retinal vein obstruction (BRVO).
  
  
  METHODS
  A retrospective study of the color photographs and fluorescein angiograms of 100 patients with unilateral BRVO (64 superotemporal and 34 inferotemporal) and a control group of 33 patients (66 eyes) with different ailments was made. The prevalence of a second isolated retinal artery, which coursed closer to the macular region, in BRVO eyes, fellow eyes and eyes of the control group was evaluated. The types and sites of arteriovenous crossings were also recorded for comparison.
  
  
  RESULTS
  The eyes with BRVO, which involved the superotemporal quadrant, had significantly larger numbers of arteriovenous crossings than did fellow eyes (p = 0.02) and control eyes (p = 0.001). In the superotemporal quadrant, a significantly higher percentage (35 of 66, 53%) of the control eyes had a second isolated retinal artery than did BRVO eyes (16 of 64 cases, 25%, p = 0.001).
  
  
  CONCLUSIONS
  The second isolated retinal artery, which has not been previously mentioned in the literature, may lower the chance of arteriovenous crossings and play a protective role in BRVO.
authors.affiliation: Department of Ophthalmology, Chang Gung Memorial Hospital, Kaohsiung, Taiwan, ROC.
authors.forename: Jong-Jer
authors.initials: JJ
authors.lastname: Lee
authors.forename: Pei-Chang
authors.initials: PC
authors.lastname: Wu
authors.forename: Chih-Hsin
authors.initials: CH
authors.lastname: Chen
authors.forename: Yung-Jen
authors.initials: YJ
authors.lastname: Chen
authors.forename: Min-Lun
authors.initials: ML
authors.lastname: Kuo
authors.forename: Chi-Chang
authors.initials: CC
authors.lastname: Liu
authors.forename: Hsi-Kung
authors.initials: HK
authors.lastname: Kuo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography; D015995:Prevalence; D012161:Retinal Artery / Q000473:pathology*; D012169:Retinal Vein / Q000473:pathology*; D012170:Retinal Vein Occlusion / Q000473:pathology*; D012189:Retrospective Studies