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 language | English (US) |
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Pages (from-to) | 292-298 |
Number of pages | 7 |
Journal | Current Eye Research |
Volume | 38 |
Issue number | 2 |
DOIs | |
State | Published - 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