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Abstract #9737 Published in IGR 5-3
Episcleral venous pressure of mouse eye and effect of body position
Aihara M; Lindsey JD; Weinreb RNCurrent Eye Research 2003; 27: 355-362
PURPOSE: To measure the episcleral venous pressure (EVP) of the mouse eye and to investigate the effect of body position on EVP and intraocular pressure (IOP). METHODS: A microneedle connected to a pressure transducer was used to measure IOP in NIH Swiss white mice. In order to measure EVP, a reservoir connected to this transducer allowed modulation of the intracameral pressure by changing its height. As intracameral pressure was gradually lowered, there was an observable reflux of erythrocytes from an episcleral vein into Schlemm's canal. The IOP at which this occurred was the endpoint of the EVP measurement. EVP and IOP were measured in a horizontal body position (0°) analogous to an awake mouse and at 30 and 60° head-down body position from the horizontal position. EVP was measured twice in each eye of six mice. RESULTS: Mean IOP at 0, 30 and 60° of head-down position was 16.5 ± 0.6, 18.2 ± 0.6, and 19.5 ± 1.8 mmHg, respectively. EVP (horizontal) was 9.6 ± 1.3 mmHg (n = 6 eyes). EVP significantly increased with increasing degree of head-down position (SNK test, p < 0.05). EVP at 30 and 60° of head-down position was 11.2 ± 1.3 and 13.3 ± 1.5 mmHg, respectively. CONCLUSIONS: Mouse EVP was successfully measured based on the detection of erythrocyte reflux from an episcleral vein into Schlemm's canal. Both EVP and IOP increased with the degree of the head-down body position.
Dr. M. Aihara, University of California San Diego, Hamilton Glaucoma Center, La Jolla, CA, USA
Classification:
5 Experimental glaucoma; animal models
6.1 Intraocular pressure measurement; factors affecting IOP (Part of: 6 Clinical examination methods)
