Intraocular pressure measurements using the TONOVET® rebound tonometer: Influence of the probe-cornea distance.

PURPOSE: To demonstrate the effect of different probe-cornea distances during intraocular pressure (IOP) data acquisition in dogs and rats. ANIMALS STUDIED: Twenty-four conscious dogs and 15 anesthetized Wistar rats. METHODS: Three interchangeable three-dimensional printed polylactide plastic spacer collars were used in place of the original Icare TonoVet® collar piece, which provided different distances (4, 6, and 8 mm) between the instrument's probe and the corneal surface. IOP values were obtained in sequence by a single observer, with the tonometer probe at a 4-, 6-, and 8-mm distance from the corneal surface. The dogs were gently restrained, and the rats were anesthetized with isoflurane. RESULTS: Intraocular pressure values obtained at 4, 6, and 8 mm from the TonoVet® probe to corneal surface distance in both dogs and rats were significantly different (P < .01). There was a small positive correlation between IOP (mm Hg) and probe-cornea distance (mm) (rs  = 0.39 for dogs and rs  = 0.51 for rats). In dogs, the mean IOP (± SD mm Hg) obtained at different distances were 16.2 ± 3.0 at 4 mm; 17.6 ± 3.4 at 6 mm; and 19.8 ± 3.8 at 8 mm. In rats, IOP values were 8.2 ± 1.5 at 4-mm; 9.4 ± 1.8 at 6-mm; and 10.5 ± 1.5 mm Hg at 8-mm distance. CONCLUSIONS: Probe-cornea distance of the Icare TonoVet® significantly affects IOP readings, even within the 4- to 8-mm range recommended by the manufacturer.

The eye of the red-eared slider turtle: morphologic observations and reference values for selected ophthalmic diagnostic tests.

PURPOSE: To perform a descriptive investigation of the red-eared slider turtle (Trachemys scripta elegans) eye, performing selected ophthalmic diagnostic tests with the aim of establishing normal reference values for this species. METHOD: Thirty adult healthy red-eared slider turtles were used to establish normal ophthalmic test values in this investigation. Selected ophthalmic tests included: collection of material for bacterial culture analysis, esthesiometry, intraocular pressure (IOP), A- and B-mode ultrasonic biometry, fundus photography, and central corneal thickness (CCT). RESULTS AND DISCUSSION: Normal parameters found for the ocular diagnostic tests were: esthesiometry: 5.84 ± 0.48 cm; IOP: 5.42 ± 1.70 mmHg; CCT: 154.5 ± 0.14 µm; palpebral fissure length: 9.71 ± 0.55 mm; modified Schirmer tear test: 2.55 ± 3.4 mm; globe axial length: 7.60 ± 0.23 mm; anterior chamber depth: 0.76 ± 0.23 mm; lens axial length: 2.45 ± 0.28 mm; vitreous chamber depth: 4.31 ± 0.42 mm. An avascular retinal pattern with nerve fibers radiating from the small white circular optic disk was observed. None of the animals had a conus papillaris. The most frequent bacteria found were Bacillus spp. (33.33%) followed by Proteus vulgaris (20.69%) and Staphylococcus aureus (18.39%). No significant differences between left and right eyes or genders were found for any of the results. Reference data and morphologic observations obtained in this investigation might help veterinary ophthalmologists to diagnose ocular diseases in the red-eared slider turtle.

Retrospective and prospective study of progressive retinal atrophy in dogs presented to the veterinary hospital of the Federal University of Parana, Brazil.

Background: Progressive retinal atrophy (PRA) is one of the main causes of blindness in dogs. Despite its clinical importance, there is limited epidemiological information available, particularly in South America. Aim: The main objective of this study was to perform a retrospective, and prospective analysis of PRA in dogs admitted at the Veterinary Hospital of the Federal University of Paraná, Brazil. Methods: Medical records of dogs admitted between 2014 and 2018 were selected through the archives of the Comparative Ophthalmology Laboratory. A total of 130 dogs with medical records indicating clinical signs suggestive of PRA, independent of the electroretinography confirmation, were selected. In order to investigate common characteristics, each patient's clinical history, ophthalmic examination, and visual status were reviewed (obstacle course, pupillary light reflex, dazzle reflex, visual tracking to a cotton ball, and menace responses). Additionally, a prospective study was performed, where flash electroretinography was performed on 30 animals with clinical signs suggestive of PRA, and 14 animals were selected for fundus photography. Data were assessed through descriptive and inferential statistics. Results: A total of 2,055 dogs were evaluated between January 2014 and December 2018. Of those, 130 animals were presumptively diagnosed with PRA (6.33%), consisting of 18 different breeds and 27 dogs with a mixed pedigree. Poodles were the most prevalent breed (n = 26; 20.00%), followed by Cocker Spaniels (n = 19; 14.62%). In the reported caseload, Pomeranians showed a considerably higher odds ratio for PRA development (15.36%). Conclusion: Pomeranians presented a high odds ratio, suggesting that further studies may be performed with breeds with a high potential for developing this disease.

Doppler ultrasonography of the pectinis oculi artery in harpy eagles (Harpia harpyja).

Twenty harpy eagles (Harpia harpyja) without systemic or ocular diseases were examined to measure blood velocity parameters of the pectinis oculi artery using Doppler ultrasonography. Pectinate artery resistive index (RI) and pulsatility index (PI) were investigated using ocular Doppler ultrasonography. The mean RI and PI values across all eyes were 0.44±0.10 and 0.62±0.20 respectively. Low RI and PI values found in the harpy eagle´s pectinis oculi artery compared with the American pekin ducks one and other tissue suggest indeed a high metabolic activity in pecten oculi and corroborates the hypothesis of a nutritional function and/or intraocular pressure regulation.

Valores eletrocardiográficos em saguis-de-tufo-preto (Callithrix penicillata) / Electrocardiographic values in marmosets (Callithrix penicillata)

Knowledge of cardiac parameters in experimental animal models is essential for comparative medical research. Our study aimed to establish electrocardiographic parameters and reference values for marmosets (Callithrix penicillata). Nineteen healthy adult marmosets were used. A combination of tiletamine and zolazepam was used for chemical restrained before performing electrocardiography (ECG). A computerized ECG machine was used. Values of the ECG parameters were a mean heart rate of 264±74 beats/min, a variation MCA between 60° and -90°, a mean P wave duration of 34±6ms and amplitude of 0.132±0.051mV, a mean PR interval duration of 56±11ms, a mean QRS complex duration of 35±7ms and amplitude of 0.273±0.269mV, a mean QT interval duration 130±26ms, ST segment was isoelectric (13 animals) and with elevation (six animals) and a mean T wave amplitude of 0.19±0.083mV and positive. There was no significant difference between males and females. Thus, the electrocardiographic parameters obtained in our study in marmosets can be used as a reference values to in other future researches, providing researchers electrocardiographic parameters that contribute with the literature.

O conhecimento de parâmetros cardíacos em animais modelo experimentais é essencial para a investigação médica comparativa. Nosso estudo teve como objetivo estabelecer parâmetros eletrocardiográficos e valores de referência para saguis-de-tufo-preto (Callithrix penicillata). Dezenove saguis-de-tufo-preto adultos saudáveis foram utilizados. Uma combinação de tiletamina e zolazepam foi empregada para contenção química antes da realização do exame eletrocardiográfico (ECG). Foi utilizado para o exame de ECG um equipamento computadorizado. Os valores dos parâmetros do ECG encontrados foram frequência cardíaca média de 264±74 bpm, uma variação do eixo cardíaco médio entre 60° e -90°, a duração da onda P média de 34±6ms e amplitude de 0,132±0,051mV, um intervalo PR com duração de 56±11ms, duração média do complexo QRS de 35±7ms e amplitude de 0,273±0,269mV, duração do intervalo QT de 130±26ms, segmento ST isoelétrico (13 animais) e com supradesnível (seis animais) e uma amplitude de onda T de 0,19±0,083mV e com polaridade positiva. Não houve diferença significativa entre machos e fêmeas. Os parâmetros eletrocardiográficos obtidos em nosso estudo em saguis-de-tufo-preto podem ser utilizados como referência em outras pesquisas futuras, oferecendo aos pesquisadores parâmetros eletrocardiográficos que contribuem com a literatura.