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Updated: Aug 7, 2026
Intravital Video Microscopy Measurements of Retinal Blood Flow in Mice
Published on: December 26, 2013
Measurement of regional choroidal blood flow in rabbits and monkeys using fluorescent microspheres
T Michael Nork1, Charlene B Y Kim, Dhanansayan Shanmuganayagam
1Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison 53792-3220, USA. tmnork@wisc.edu
Objective:
To develop a quantitative measure of regional variation in choroidal blood flow (ChBF).
Methods:
Five million 15-microm fluorescent microspheres were injected into the left ventricles of 4 rabbits and 3 monkeys. The fixed globes were bleached, flat mounted, and photomicrographed. After image analysis to locate each microsphere, regional densities and blood flow were determined.
Results:
Regional variation in ChBF was clearly evident. In the rabbit, a high density of spheres was seen in the visual streak. This was surrounded by a middle peripheral area of low sphere density and a far peripheral region of moderately high density. In the monkeys, sphere density was markedly greater in the macula compared with the periphery. Contour plots produced lines of constant flow that were oval and extended farther nasally than temporally in the monkeys. The ratio of central to peripheral ChBF was much greater in the monkeys than in the rabbits.
Conclusion:
Quantitative assessment of regional ChBF can be performed using a modification of the fluorescent microsphere impaction method.
Clinical Relevance:
This method of determining regional ChBF will be useful for studying the vascular effects of pharmacologic agents and for characterizing animal models of human disease involving the outer retina.
Insights
Researchers developed a new method to measure regional choroidal blood flow (ChBF) using fluorescent microspheres. This technique reveals significant variations in ChBF across different eye regions in rabbits and monkeys.
Area of Science:
- Ophthalmology
- Physiology
- Medical Imaging
Background:
- Choroidal blood flow (ChBF) is crucial for retinal health.
- Understanding regional ChBF variations is important for diagnosing and treating eye diseases.
- Current methods for assessing regional ChBF are limited.
Purpose of the Study:
- To develop a quantitative method for measuring regional variations in choroidal blood flow (ChBF).
- To establish a reliable technique for assessing ChBF distribution in animal models.
Main Methods:
- Injection of fluorescent microspheres into the left ventricles of rabbits and monkeys.
- Flat mounting and photomicrography of fixed globes.
- Image analysis to determine regional microsphere density and calculate blood flow.
Main Results:
- Significant regional variations in ChBF were observed in both rabbits and monkeys.
- Rabbits showed high ChBF in the visual streak, low in the middle periphery, and moderate in the far periphery.
- Monkeys exhibited higher macular ChBF compared to the periphery, with distinct nasal-temporal asymmetry in flow patterns.
Conclusions:
- A modified fluorescent microsphere impaction method allows for quantitative assessment of regional ChBF.
- This method is valuable for studying the vascular effects of drugs and for characterizing animal models of outer retinal diseases.
