Cronicon OPEN ACCESS EC OPHTHALMOLOGY EC OPHTHALMOLOGY Research Article Effects of Isoflurane and Midazolam on Tear Production and Intraocular Pressure in Capuchin Monkeys (Sapajus libidinosus) Paula Diniz Galera 1 *, Ricardo Miyasaka de Almeida 1 , Cecília Azevedo Dias Lopes 2 , Layla Karolaynne Souza Cruz 3 and Fabiano Montiani-Ferreira 4 1 College of Agronomy and Veterinary Medicine, University of Brasília, Brasilia, DF, Brazil 2 College of Veterinary Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, DF, Brazil 3 Autonomous Veterinary, Brasilia, DF, Brazil 4 Department of Veterinary Medicine, Federal University of Paraná, PR, Brazil Citation: Paula Diniz Galera., et al. “Effects of Isoflurane and Midazolam on Tear Production and Intraocular Pressure in Capuchin Mon- keys (Sapajus libidinosus)”. EC Ophthalmology 12.2 (2021): 47-54. *Corresponding Author: Paula Diniz Galera, College of Agronomy and Veterinary Medicine, University of Brasília, Brasilia, DF, Brazil. Received: December 16, 2020; Published: Janaury 30, 2021 Abstract Background: Anesthetics may be necessary for ophthalmic examination in capuchin monkeys and may affect the intraocular pres- sure (IOP) or aqueous tear production; therefore, these may be of concern when performing these evaluations. Aim: To evaluate the influence of isoflurane alone, or combined with midazolam, on tear production by STT and on IOP by applana- tion and rebound tonometry in S. libidinosus. Methods: Thirty-eight monkeys received isoflurane (n = 16), midazolam-isoflurane (n = 12), or physical restraint (control; n = 10) for evaluation of aqueous tear production (STT) and IOP (applanation or rebound tonometry). Results: Anesthesia lowered STT values. Isoflurane was not significantly different compared to midazolam-isoflurane (P = 0.59) or control (P = 0.06); however, STT was significantly more reduced in midazolam-isoflurane compared to control (P = 0.01). IOP showed no significant differences among groups (P > 0.05), but rebound tonometry resulted in higher IOP values when compared to applana- tion tonometry values (P = 0.02). There were no significant differences in STT and IOP between right and left eyes or between males and females (P > 0.05). Conclusion: Midazolam-isoflurane reduced aqueous tear production; however, IOP was not affected by either restraint protocol. Keywords: Anesthesia; Intraocular Pressure; Monkey; Primate; Schirmer Tear Test Introduction Among New World primates, the capuchin monkey (Sapajus libidinosus) reproduces easily in captivity and is not considered an en- dangered species, except for its subspecies, the black-striped capuchin (S. libidinosus flavius) [1-3]. Primates kept in captivity are of great importance in research, increasing the demand for specialized medical care, including veterinary ophthalmology [4,5]. Capuchin monkeys have evolutionarily converged with humans and chimpanzees in several ways, including large brain size, omnivory, and extractive forag- ing, extensive cooperation and coalitionary behavior and a reliance on social learning [6]. Investigating capuchin monkeys have drawn increasing interest from researchers in comparative studies of the visual system, given their close behavioral, biological and phylogenetic relationship with humans [7]. Tear production and intraocular pressure (IOP) diagnostic tests are of the utmost importance in research of dry eye models like mon- keys [8] and in animals with uveitis and glaucoma [9,10], respectively. These tests are important components of a complete ophthalmic examination and were previously evaluated in non-sedated [4] and sedated [11,12] Capuchin monkeys.