Effects of the Ottonia martiana Miq. (Piperaceae) extract on dog's ocular surface

The anesthetics effects of aqueous extract of Ottonia martiana leaves were studied on the ocular surface of healthy beagle dogs. The dogs were divided in three groups (n=15): control group (CG), proxymetacaine group (PG) and Ottonia group (OG), which were treated with 0.9% saline, 0.5% proxymetacaine hydrochloride ophthalmic solution and O. martiana extract respectively. An oftalmic evaluation was performed before the treatments. Eye drops were instilled at time 0 (T0) and 3 minutes later (T3). Axial corneal sensitivity was evaluated by esthesiometry 5 and 10 minutes after T0. Tear production and intraocular pressure were evaluated 10 minutes after T0. Slit lamp biomicroscopy was performed 10 and 20 minutes after T0 and the eyes were stained with fluorescein 20 minutes after T0. The STT was reduced in PG. Conjunctival hyperemia was observed in 13 animals from PG and constituted the only ocular alteration observed during the study. Esthesiometry revealed a decreased corneal sensitivity for PG and OG. Those results show that the O. martiana extract acts reducing corneal sensitivity in dogs. Moreover, its use does not decrease the tear production and does not cause any clinical ophthalmic alteration