Conventional and uveo-scleral drainage of aqueous humour in the cynomolgus monkey (Macaca irus) at normal and high intraocular pressures

It is suggested that, in the pressure region investigated, a change in intraocular pressure produces almost the same change in tissue pressure in the uvea and in the suprachoroid and that this explains why the outflow by way of uveo-scleral routes was so alike at the different pressures investigated.

Abstract

[131I]Albumin and [125I]-γ-globulin were used to mark the bulk flow of aqueous humour in young cynomolgus monkeys. In living animals, at a normal intraocular pressure of about 11 mmHg, the net formation of aqueous humour was 1·24 ± 0·13 μl/min. The rate of drainage by way of uveo-scleral routes was 0·44 ± 0·06 μl/min and by way of conventional routes was 0·80 ± 0·11 μl/min. At an intraocular pressure artificially raised to 22 mmHg by an extra inflow, the outflow from the anterior chamber by way of uveo-scleral routes was 0·63 ± 0·08 μl/min and by way of conventional routes was 4·18 ± 0·12 μl/min. It is suggested that, in the pressure region investigated, a change in intraocular pressure produces almost the same change in tissue pressure in the uvea and in the suprachoroid and that this explains why the outflow by way of uveo-scleral routes was so alike at the different pressures investigated. After death, at an intraocular pressure artificially raised to 14 mmHg by an inflow of about 5 μl/min, the mean outflow from the anterior chamber by way of uveo-scleral routes was 1·25 ± 0·17 μl/min.