The canine eye: lens depression and aqueous outflow.

The effects on facility of outflow of lens depression (controlled mechanical retrodisplacement of the crystalline lens to simulate cyclotonia in excised eye preparations), prolonged perfusion, and intracameral hyaluronidase were evaluated in 16 pairs of freshly excised canine eyes. Lens depression increased facility of aqueous outflow by an amount greater than could be attributed to mechanical or temporal disruption of the hyaluronidase-sensitive outflow barrier and appears to act, at least in part, on the hyaluronidase-resistant portion of the outflow barrier. These data suggest that in addition to accelerating the washout effect, mechanical tension on the iridocorneal angle in the dog increases facility of aqueous outflow in a manner similar to the direct trabecular component of cyclotonic-induced facility increases observed in primate eyes.