Safety and efficacy of unilateral topical application of rocuronium bromide in healthy scops owls (Otus scops).

Objective: To evaluate the safety and efficacy of unilateral topical application of rocuronium bromide in scops owls. Animals studied: Ten healthy adult scops owls. Procedures: Birds weighting between 82-111 g were enrolled. Complete physical and ophthalmic examinations were performed. Each animal received a single dose of 0.15 mg of rocuronium bromide (30 µL) in a randomly selected eye. Static pupillometric evaluations were performed before and after drug instillation at 0, 30, 60, 90, and 120 minutes, in a room with fixed light intensity. Physical and ophthalmic examinations were carried out to evaluate possible adverse effects. Results: Median pupil (95% CI) size at t ₀ was 7.10 mm (5.51-7.41) for placebo eyes and 7.22 mm (6.93-7.48) for treated eyes, showing no statistical differences (P >.05). When compared to the placebo eye, significant mydriasis was achieved at t ₃₀ [8.18 mm (7.22-9.00)] (P =.014) and lasting until t ₉₀ [7.35 mm (6.20-9.52)] (P =.004). Maximal mydriasis was obtained at t ₆₀ [8.63 mm (7.72-9.81)] (P =.001). During this period, the treated eye no longer responded to direct light stimulation. Complete mydriasis was observed in 5/10 birds (mean weight 97.4 g). Pupil size at t ₉₀ and t ₁₂₀ did not differ from baseline (P >.05) in treated eyes. No adverse effects were seen during the study period. Conclusion: Single-dose topical rocuronium bromide (0.15 mg) is a safe and effective medium duration mydriatic agent in scops owls. Further studies are needed to evaluate bilateral topical application and standardize the mydriatic protocol.