The aqueous humor drainage mechanism in the cynomolgus monkey (Macaca irus) with evidence for unconventional routes.

I The aqueous in freshly killed cynomolgus monkeys ivas replaced hy a solution of I-albumin and "I-diodone (iodopyracet). An inflow of this solution into the anterior chamber was produced by a horizontal buret placed above the eye, and at the same time the eye was continuously loashed through with the radioactive solution at a high rate by a push-pull arrangement. Fluid was collected from the denuded anterior sclera in 1 minute samples over a period of 25 minutes. The same type of experiments was performed with I—gamma globulin and I-albumin. In the effluent, albumin and gamma globulin reached an apparently steady concentration after 1 minute, while throughout the experiments the diodone concentration in the effluent remained lower than expected from, a bulk flow through well-defined channels. The low concentration was due to a rapid diffusion of diodone into the tissues of the limbus region. The labeled albumin entered the uvea and the sclera in such amounts as to indicate that about 20 per cent of the labeled fluid had passed out by way of unconventional uveoscleral routes. The results suggest that more than 90 per cent of the conventional drainage was carried by pores xoith an apparent diameter of more than 0.16 n.