The measurement of pseudofacility and true facility by constant pressure perfusion in the normal rhesus monkey eye.

Facility of bulk aqueous humor outflow via conventional channels, true facility, and pressure sensitive suppression of aqueous humor inflow, pseudofacility, were measured by constant pressure perfusion in 24 eyes of 12 rhesus monkeys. True facility was found to have a mean value of 0.55 ,uL minr mm. Hg~ and pseudofacility was found to have a mean value of 0.12 p.L minr mm. Hg-. This figure is in general agreement ivith other published values for pseudofacility in a variety of species. It is concluded that suppression of formation of aqueous humor by elevation of intraocular pressure exerts a small but significant stabilizing effect on the intraocular pressure in the normal eye. It is speculated that pseudofacility may have a much greater relative influence on intraocular dynamics in disease states in which the conventional outflow pathways are pathologically occluded.