BASELINE ASSESSMENT OF OPHTHALMIC PARAMETERS IN THE GREATER ONE-HORNED RHINOCEROS (RHINOCEROS UNICORNIS)

Abstract

Five healthy captive greater one-horned rhinoceroses (Rhinoceros unicornis) were evaluated with standing sedation (detomidine hydrochloride 20-30 mg and butorphanol tartrate 50-60 mg per animal) to determine baseline values for tear production, intraocular pressure (IOP), conjunctival flora, and ocular anatomy using brightness mode transpalpebral ultrasonography with a 4- to 7-MHz broadband curvilinear transducer. The mean Schirmer tear test I value was 18.2 ± 3.49 mm/min. The mean IOP measured using applantation tonometry was 31.2 ± 6.62 mm Hg. Ocular biometry measurements were the following: axial length 2.61 ± 0.11 cm; corneal thickness 0.13 ± 0.01 cm; anterior segment depth 0.28 ± 0.06 cm; lens depth 0.70 ± 0.11 cm; and posterior segment depth 1.46 ± 0.13 cm. These values indicate that the globe is smaller than that of the domestic horse. All eight conjunctival swabs cultured bacterial and fungal microorganisms, with the most common being Staphylococcus spp. (57%). All bacterial isolates were considered to be commensal organisms due to the presence of mixed bacterial populations and lack of clinical signs of ocular disease. The data collected in this study should provide veterinarians with baseline information to assist in the diagnosis of ophthalmic conditions in the greater one-horned rhinoceros.

Allometry and Scaling of the Intraocular Pressure and Aqueous Humour Flow Rate in Vertebrate Eyes

“…The aim of the systematic review was to collect typical IOPs for healthy adult species of vertebrates; therefore, some aspects of the variations in IOP within each group of vertebrates were not included in the study. While in healthy animals the IOP is generally not significantly different in the left and right eye [ 40 , 41 , 43 , 53 , 56 – 59 , 64 – 66 , 69 , 74 – 76 , 79 , 85 , 88 , 91 , 92 , 98 , 103 , 111 , 114 , 114 , 117 , 122 – 127 , 132 ] or in males and females [ 41 , 43 , 56 , 58 , 63 , 65 , 69 , 74 , 75 , 79 , 85 , 88 , 91 , 92 , 103 , 114 , 121 – 124 , 126 , 132 , 133 ], it has been found to change with position in flamingos and bats. [ 59 , 60 , 114 ].…”

Anatomical, Histological and Histochemical Observations of the Eyelids and Orbital Glands in the Lowland Tapir (Tapirus terrestris Linnaeus, 1785) (Perissodactyla: Ceratomorpha)

“…Ophthalmic cases in the horse and donkey are reported more frequently and to a lesser extent in rhinoceros [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. The morphology of the eyeball and adnexa of the eye has been described more frequently in the family Equidae: donkeys, horses and the Rhinocerotidae family [ 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ].…”

“…Ophthalmic cases in the horse and donkey are reported more frequently and to a lesser extent in rhinoceros [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. The morphology of the eyeball and adnexa of the eye has been described more frequently in the family Equidae: donkeys, horses and the Rhinocerotidae family [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60].…”