Effects of auriculopalpebral nerve block on ocular parameters in dogs

ABSTRACT

The objective of this study was to compare the effects of two local anesthetics used on auriculopalpebral block on eyelid akinesia, tear production, intraocular pressure (IOP) and tear break-up time (TBUT) in conscious dogs. A blind, randomized, prospective study was conducted to determine the effects of auriculopalpebral block using ropivacaine 0.75% and bupivacaine 0.5% in 12 healthy non-brachycephalic dogs (24 eyes). Threat response and eyelid reflex tests, Schirmer tear test (STT), IOP and tear break-up time were conducted before blockage and at 30, 60, 120, 240 and 360 minutes after application. A difference was observed between the values found at 30, 60, 120 and 240 minutes compared to baseline for threat response and eyelid reflex tests in the two groups evaluated, proving eyelid akinesia after blockages. No difference was found for STT, IOP and TBUT between baseline values and post-anesthesia times or between groups. It was possible to conclude that ropivacaine and bupivacaine on auriculopalpebral block in conscious dogs promoted eyelid akinesia for at least 240 minutes, not altering ocular physiological parameters of tear production, intraocular pressure, and tear break-up time after blockages.