Quantitative retinal and choroidal blood flow during light, dark adaptation and flicker light stimulation in rats using fluorescent microspheres

Yen Yu I. Shih, Lin Wang, Bryan H. De La Garza, Guang Li, Grant Cull, Jeffery W. Kiel, Timothy Q. Duong

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Purpose: The present study aimed to quantify retinal and choroidal blood flow (BF) during light, dark adaptation and flicker light stimulation using the microsphere technique. Materials and Methods: Adult male Sprague-Dawley rats were anesthetized with isoflurane. Eyes were dark (Group I, n = 8), light (Group II, n = 8) adapted or stimulated with 10 Hz flicker light (Group III, n = 10). Retinal and choroidal BF were measured by a previously established method, using a mixture of 8 μm yellow-green and 10 μm red fluorescent microspheres. The microspheres were counted ex vivo in the dissected retina and choroid and in the reference arterial blood under a fluorescent microscope. Results: The choroidal BF was 64.8 ± 29 μl/min (mean ± SD) during dark adaptation, not significantly different from that during light adaptation (66.0 ± 17.8 μl/min). The retinal BF was 13.5 ± 3.2 μl/min during 10 Hz flickering light stimulation, significantly higher than that during dark adaptation in the control fellow eyes (9.9 ± 2.9 μl/min). The choroidal BF values were not statistically different between flicker stimulation and dark adaptation. Retinal BF was 11.6 ± 2.9 μl/min during light adaptation. Dark adaptation did not increase retinal BF (Group I, 8.2 ± 2.4 μl/min; Group II, 9.9 ± 2.9 μl/min). Conclusions: These findings argue against a dark-induced or flicker-induced functional hyperemia in the choroid as a result of the demands of the outer retina. Retinal BF was not higher during dark adaptation. Our data support the conclusion that the inner retina has a higher energy demand in flicker conditions relative to dark.

Original languageEnglish (US)
Pages (from-to)292-298
Number of pages7
JournalCurrent Eye Research
Volume38
Issue number2
DOIs
StatePublished - Feb 2013

Keywords

  • Blood flow
  • Choroid
  • Dark adaptation
  • Flicker light stimulation
  • Light adaptation
  • Microspheres
  • Rat
  • Retina

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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