Br J Ophthalmol 1998;82:821-825 ( July )
Relation between pressure determined by ophthalmodynamometry and
aortic pressure in the dog
William H Morgan,
Dao-Yi Yu,
Valerie A Alder,
Stephen J Cringle,
Ian J Constable
McCusker Glaucoma
Centre, Centre for Ophthalmology and Visual Science, University of
Western Australia, Australia
Correspondence to: W H Morgan, McCusker Glaucoma Centre, Centre for Ophthalmology and
Visual Science, University of Western Australia, 2 Verdun Street,
Nedlands, WA, Australia, 6009.
; Accepted for publication 22 January 1998
AIMS
Ophthalmodynamometry
has been used extensively since the last century; however, controversy
surrounds what it actually measures. This study was set up to determine
the relation between ophthalmodynamometric (ODP) and systemic blood pressures.
METHODSAortic
pressure was continuously monitored and altered by phlebotomy in six
anaesthetised dogs, while ophthalmodynamometry was performed, by
directly altering intraocular pressure. Maxillary artery pressure was
monitored in two animals. All pressure transducers were zeroed at eye level.
RESULTSMean ODP was
96.6% (1.6%) (95% confidence interval, n = 49) of aortic pressure.
Mean maxillary artery pressure was 95.7% (5.5%) (95% CI, n = 16) of
aortic pressure. ODP was 1.9 (0.6) mm Hg (95% CI, n = 33) higher than
maxillary artery pressures.
CONCLUSIONODP was
only slightly below aortic pressure and not significantly different
from maxillary artery pressure, the analogue of the internal carotid
artery in humans. These results also suggest a retinal artery collapse
pressure of at least 1.9 mm Hg.
Keywords:
ophthalmodynamometry;
dog;
arterial pressure
© 1998 by British Journal of Ophthalmology
