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Ocular blood flow in dogs using radiolabelled microspheres
M S Roy1, K S Harrison, E Harvey
1Clinical Branch, National Eye Institute, Bethesda, Maryland.
International Journal of Radiation Applications and Instrumentation. Part B, Nuclear Medicine and Biology
|January 1, 1989
Summary
Radioactive microspheres accurately measured canine ocular and uveal blood flow. Retinal blood flow was approximately 1% of total ocular flow, though measurements were less reproducible.
Area of Science:
- Ophthalmology
- Veterinary Medicine
- Physiology
Background:
- Accurate measurement of ocular blood flow is crucial for understanding and treating various eye diseases.
- Previous methods for assessing ocular hemodynamics have limitations in reproducibility and precision.
Purpose of the Study:
- To determine the rate of blood flow through different segments of the canine eye using radioactive microspheres.
- To evaluate the reproducibility of microsphere-based measurements for total ocular, uveal, and retinal blood flow.
Main Methods:
- Radioactive microspheres of two distinct sizes (15 +/- 5 microns and 25 +/- 5 microns) were administered to dogs.
- Ocular blood flow was quantified by measuring radioactivity in different eye tissues.
- Reproducibility of flow measurements was assessed.
Main Results:
- Microsphere sizes of 15 +/- 5 microns and 25 +/- 5 microns yielded reproducible measurements for total ocular and uveal blood flow.
- Retinal blood flow constituted approximately 1% of the total ocular blood flow.
- Retinal blood flow measurements exhibited poor reproducibility, attributed to the limited number of microspheres trapped in retinal vessels.
Conclusions:
- Radioactive microspheres are a viable tool for reproducible measurement of total ocular and uveal blood flow in dogs.
- Retinal blood flow is a small fraction of total ocular flow, and its measurement requires further refinement for improved reproducibility.