title: The relationship of macular microcirculation to visual acuity in diabetic patients.
abstract: OBJECTIVE
  To assess the perifoveal microcirculation in diabetic maculopathy without clinically significant macular edema and its relationship to visual acuity.
  
  
  METHODS
  Prospective analysis.
  
  
  METHODS
  A teaching hospital.
  
  
  METHODS
  Fifteen patients with impaired visual acuity of 20/50 or worse, a diabetic control population with unaffected visual acuity (matched age, gender, retinopathy stage), and 52 healthy controls were enrolled.
  
  
  METHODS
  Study consisted of video-fluorescein angiography with image analyses and hemoglobin A1c measurements.
  
  
  METHODS
  Macular capillary blood velocity, capillary density (perifoveal intercapillary area), and foveal avascular zone.
  
  
  RESULTS
  The capillary blood velocity was significantly reduced in both diabetic groups (P < .001) when compared with healthy controls, but did not differ significantly among the two diabetic groups. The perifoveal intercapillary area and foveal avascular zone were significantly enlarged in both diabetic groups compared with healthy controls (P < .001). The foveal avascular zone (P < .01) and perifoveal intercapillary area (P = .01) were further enlarged in the diabetics with reduced visual acuity. The visual acuity correlated significantly with foveal avascular zone (R2 = .51) and perifoveal intercapillary area (R2 = .24), indicating an association between enlargement and declined visual acuity.
  
  
  CONCLUSIONS
  Capillary blood velocity remained unchanged regardless of presence of visual impairment, whereas foveal avascular zone and perifoveal intercapillary area indicated ischemia. This may help in defining a critical hypoxic threshold for visual loss and identifying the presence of an ischemic diabetic maculopathy.
authors.affiliation: Medical Faculty, Technical University of Aachen, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Arend
authors.forename: S
authors.initials: S
authors.lastname: Wolf
authors.forename: A
authors.initials: A
authors.lastname: Harris
authors.forename: M
authors.initials: M
authors.lastname: Reim
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D005260:Female; D005451:Fluorescein Angiography; D005584:Fovea Centralis / Q000098:blood supply; D005654:Fundus Oculi; D006801:Humans; D007511:Ischemia / Q000503:physiopathology; D007834:Lasers; D008266:Macula Lutea / Q000098:blood supply*; D008297:Male; D008833:Microcirculation / Q000502:physiology; D008875:Middle Aged; D019721:Ophthalmoscopes; D011446:Prospective Studies; D012171:Retinal Vessels / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology*