Aqueous humor outflow in beagles with inherited glaucoma: constant pressure perfusion.

Determination of facility of aqueous humor outflow (C), using constant pressure perfusion, was performed in vivo in normal dogs and in Beagles with inherited glaucoma at different stages of the disease process. Measurements were taken at 10 mm of Hg increments of intraocular pressure (IOP) from 10 to 50 mm of Hg IOP in the controls and to higher levels of IOP, as needed, to obtain 3 consecutive intervals in which perfusion was required in glaucomatous animals. In normal dogs, C increased slightly as IOP increased to a maximum of 0.22 at 50 mm of Hg. In glaucomatous dogs, C was significantly (P = 0.001) reduced compared with the value in the controls, with a maximum value of 0.09 at 50 mm of Hg.