A pilot study of in vivo venous pressures in the pig retinal circulation.
Retinal venous pressure was examined in six pigs using a balanced servo-nulling micropuncture technique. The mean transmural venous pressure was 0.95 mmHg (SD 1.50 mmHg). The transmural venous pressure was lower at the optic disc than away from the disc (0.32 +/- 1.46 mmHg vs 1.69 +/- 1.19 mmHg, P < 0.01). At the disc a transmural pressure of zero or less (0 to -0.5 mmHg) was demonstrated in 10/21 (48%) of the disc readings. Over an intraocular pressure range of 15-26 mmHg there was a strong correlation between intraocular pressure and retinal venous pressure (Pearson coefficient r = 0.92). The results are compatible with the Starling resistor theory of venous outflow from the eye.
Westlake
W H
WH
Centre for Ophthalmology and Visual Sciences, Lions Eye Institute, University of Western Australia, Nedlands, Australia. westlake@networx.net.au
Morgan
W H
WH
Yu
D Y
DY
D000818:Animals; D001775:Blood Circulation; D005260:Female; D007429:Intraocular Pressure; D009898:Optic Disk / Q000098:blood supply; D010865:Pilot Projects; D011677:Punctures; D012169:Retinal Vein / Q000502:physiology*; D013552:Swine; D014690:Venous Pressure / Q000502:physiology*