title: Effect of aging on retinal macular microcirculation: a blue field simulation study.
abstract: OBJECTIVE
  Structural changes in the retina are known to occur with aging. This study was performed to investigate whether aging also affects the retinal macular microcirculation.
  
  
  METHODS
  Healthy volunteers with ages ranging from 20 to 78 years (mean +/- SD, 49 +/- 19 years) were included in this study. The retinal macular microcirculation was assessed with the blue field simulation technique, based on the blue field entoptic phenomenon. Subjects were asked to match the velocity and density of computer-simulated particles displayed on a screen with those of their entoptically observed leukocytes. Ten matching trials were performed, and an average leukocyte velocity and density were calculated.
  
  
  RESULTS
  Significant negative linear correlations were observed between velocity and age (P = 0.0001) and density and age (P = 0.009). Older subjects (50 to 78 years of age) had a significantly slower velocity (0.61 +/- 0.21 mm/s) and smaller density (90 +/- 43 particles per field of view) than younger subjects (0.92 +/- 0.12 mm/s and 135 +/- 65 particles, respectively; unpaired Student's t-test, P = 0.001 and P = 0.01, respectively).
  
  
  CONCLUSIONS
  These results suggest that, in normal subjects, retinal macular blood flow decreases with age. The 20% decrease in average velocity with age is very similar to the age-related decrease in number of cells observed in the human foveal ganglion cell layer.
authors.affiliation: Department of Ophthalmology, Scheie Eye Institute, School of Medicine, University of Pennsylvania, Philadelphia 19104.
authors.forename: J E
authors.initials: JE
authors.lastname: Grunwald
authors.forename: J
authors.initials: J
authors.lastname: Piltz
authors.forename: N
authors.initials: N
authors.lastname: Patel
authors.forename: S
authors.initials: S
authors.lastname: Bose
authors.forename: C E
authors.initials: CE
authors.lastname: Riva
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D003198:Computer Simulation; D006801:Humans; D007429:Intraocular Pressure; D007958:Leukocyte Count; D007962:Leukocytes / Q000502:physiology; D008266:Macula Lutea / Q000098:blood supply*; D008833:Microcirculation; D008875:Middle Aged; D012171:Retinal Vessels / Q000502:physiology*; D014787:Vision Tests / Q000379:methods