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[Effect of mannitol on human retinal blood flow]
1Department of Ophthalmology, Aoyama Hospital, Japan.
Nippon Ganka Gakkai Zasshi
|October 1, 1994
Summary
Hyperosmotic agents like 20% mannitol significantly increase retinal blood flow rate and velocity in normal subjects. This effect was more pronounced than with saline, suggesting potential therapeutic applications for retinal circulation.
Area of Science:
- Ophthalmology
- Physiology
Background:
- Retinal circulation is crucial for visual function.
- Understanding the impact of systemic agents on retinal hemodynamics is important for managing ocular conditions.
Purpose of the Study:
- To investigate the effects of 20% mannitol, a hyperosmotic agent, on retinal circulation in healthy individuals.
- To compare the effects of mannitol with physiological saline on retinal blood flow parameters.
Main Methods:
- Employed laser speckle retinal blood flow velocimetry and real-time retinal vessel diameter measurement.
- Utilized a double-masked crossover design with 7 normal subjects (14 eyes).
- Administered intravenous 20% mannitol or physiological saline and measured parameters before and after.
Main Results:
- 20% mannitol significantly reduced intraocular pressure and increased ocular perfusion pressure, retinal blood flow velocity, and retinal blood flow rate (p < 0.01).
- Physiological saline did not significantly alter retinal blood flow rate (p > 0.05) but increased velocity (p < 0.05).
- The increase in retinal blood flow rate after mannitol was significantly greater than after saline (p < 0.05).
Conclusions:
- 20% mannitol administration enhances retinal blood flow in healthy individuals.
- Mannitol's effects on retinal circulation are superior to physiological saline.
- These findings suggest potential therapeutic benefits of mannitol in conditions affecting retinal perfusion.