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Postural changes in perfusion pressure and retinal arteriolar calibre
1Research Department of Ophthalmology, Royal College of Surgeons of England, London.
The British Journal of Ophthalmology
|April 1, 1988
Summary
Ophthalmic artery perfusion pressures and retinal arteriole size change with body position. Some changes were autoregulatory, while others were not, indicating complex vascular responses.
Area of Science:
- Ophthalmology
- Physiology
- Vascular Biology
Background:
- The ophthalmic artery is crucial for ocular blood supply.
- Retinal arterioles are key indicators of ocular vascular health.
- Understanding vascular responses to postural changes is vital for ophthalmic physiology.
Purpose of the Study:
- To investigate ophthalmic artery perfusion pressures.
- To examine retinal arteriolar calibre changes in response to postural variations (sitting, standing, lying).
- To assess the autoregulatory capacity of retinal arterioles during these positional shifts.
Main Methods:
- Studied 10 human subjects.
- Measured ophthalmic artery perfusion pressures.
- Assessed retinal arteriolar calibres in sitting, standing, and lying positions.
Main Results:
- Observed differing responses in perfusion pressure across postural changes.
- Identified autoregulatory responses in a significant proportion of retinal arteriolar calibre changes (13/18 from sitting to standing; 13/22 from standing to lying).
- Found non-autoregulatory responses where arterioles dilated with increased perfusion pressure and constricted with decreased pressure.
Conclusions:
- Retinal arterioles exhibit varied autoregulatory responses to changes in body position.
- Both autoregulatory and non-autoregulatory vascular mechanisms are involved in maintaining ocular blood flow during postural shifts.
- These findings contribute to understanding ocular hemodynamics and autoregulation.