title: Correlation between higher blood flow velocity in the central retinal vein than in the central retinal artery and severity of nonproliferative diabetic retinopathy.
abstract: OBJECTIVE
  To assess the correlation between a higher blood flow velocity in the central retinal vein (CRV) than in the central retinal artery (CRA) and the severity of nonproliferative diabetic retinopathy (non-PDR).
  
  
  METHODS
  We evaluated both eyes of 20 non-PDR patients with higher peak systolic velocity (PSV) in the CRV than in the CRA unilaterally as determined by color Doppler imaging (CDI). The eyes with higher PSV in the CRV were placed in group D2-H, and the fellow eyes were placed in group D2-L. The stage of non-PDR was determined by the guidelines of the Early Treatment Diabetic Retinopathy Study. Normal subjects and non-PDR patients without higher PSV in the CRV were evaluated as CDI controls.
  
  
  RESULTS
  Advanced non-PDR (P=0.001) and cystoid macular edema (P=0.02) were statistically more frequent in group D2-H. The velocities in the ophthalmic artery and the short posterior ciliary artery were not statistically different among all groups. The velocities in the CRA were similar in all non-PDR groups and significantly lower than in the normal subjects (P<0.05). The velocities in the CRV were significantly higher only in group D2-H (P<0.001).
  
  
  CONCLUSIONS
  Higher PSV in the CRV than in the CRA was significantly correlated with the severity of non-PDR, especially in the presence of cystoid macular edema.
authors.affiliation: Department of Ophthalmology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan. fujiokas@kcn.ne.jp.
authors.forename: Sayuri
authors.initials: S
authors.lastname: Fujioka
authors.affiliation: Department of Ophthalmology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan.
authors.forename: Kaoruko
authors.initials: K
authors.lastname: Karashima
authors.affiliation: Department of Ophthalmology, Osaka Police Hospital, Osaka, Japan.
authors.forename: Norikiyo
authors.initials: N
authors.lastname: Nishikawa
authors.affiliation: Department of Ophthalmology, Osaka National Hospital, Osaka, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Saito
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology*; D003930:Diabetic Retinopathy / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D005451:Fluorescein Angiography; D005500:Follow-Up Studies; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012161:Retinal Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012169:Retinal Vein / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D018615:Ultrasonography, Doppler, Color