Tear production, intraocular pressure, and central corneal thickness in white-tailed deer (Odocoileus virginianus).

OBJECTIVE: To evaluate the tear production, intraocular pressure, and central corneal thickness in healthy white-tailed deer (Odocoileus virginianus) and assess for seasonal variability. ANIMALS STUDIED: Nineteen healthy fawns (3-10 days old) and 8 healthy adult white-tailed deer (164-280 days old) were studied. PROCEDURES: All fawns were manually restrained for the study, while adult animals were immobilized with an intramuscular injection of combined xylazine (2.2 mg/kg), tiletamine (1 mg/kg), and zolazepam (1 mg/kg). Tear production (STT-1) was evaluated in both eyes of all fawns. Intraocular pressure (applanation and rebound tonometry) and central corneal thickness (ultrasound pachymetry) were determined in both eyes of all fawns and adult deer. RESULTS: Mean ± SD tear production in fawns was 12.32 ± 4.46 mm/min. Mean ± SD IOP values in the fawns were 16.21 ± 4.97 mm Hg (TonoPen® ) and 14.05 ± 5.03 mm Hg (TonoVet® ). In adult deer, mean ± SD IOP values were 15.57 ± 2.88 mm Hg with TonoPen® and 12.87 ± 2.57 with TonoVet® , and TonoPen® significantly overestimated the IOP, compared to TonoVet® (P < 0.005). The IOP was not significantly different between young and adult animals (P = 0.22). A significant difference (P < 0.005) in CCT values was observed between fawns (528.42 ± 27.65 µm) and adult deer (747.55 ± 41.60 µm). CONCLUSIONS: This study reports normal values of tear production in healthy fawns, and intraocular pressure and central corneal thickness in healthy young and adult white-tailed deer.

Evaluation of pigment epithelium-derived factor concentration in equine amniotic membrane homogenate and its in-vitro vascular endothelial growth factor inhibition effect in tears of dogs with vascularized ulcerative keratitis.

Background: Corneal neovascularization can result from many pathological processes affecting the ocular surface leading to disturbances and opacifications that reduce corneal clarity and may impact vision. In veterinary medicine, the use of topical corticosteroid is contraindicated in the presence of ulcerative keratitis, and there is sparse research regarding safe medical alternatives to inhibit corneal neovascularization in dogs to improve visual outcome. Aim: To investigate the pigment epithelium-derived factor (PEDF) concentration in equine amniotic membrane homogenate (EAMH) and its in-vitro vascular endothelial growth factor (VEGF) inhibition in tears of dogs with vascularized ulcerative keratitis. Methods: Homogenates from 10 equine amniotic membranes (AM) were analyzed by sandwich enzyme-linked immunosorbent assay (ELISA) for quantification of equine PEDF and VEGF. Forty tear samples were collected from both eyes of dogs diagnosed with vascularized ulcerative keratitis, and 50 samples from healthy dogs. Samples from affected eyes were allocated to G1 - affected undiluted tears; G2 - affected tears diluted with phosphate-buffer solution; G3 - affected tears treated with low-concentrated EAMH; and G4 - affected tears treated with high-concentrated EAMH. Tears from the unaffected contralateral eyes were composed in G5, while G6 was composed by tears from healthy dogs (control). The presence and levels of VEGF were evaluated in all groups by Western blot and ELISA. Results: The PEDF:VEGF ratio in EAMH was 110:1. An increase in VEGF levels was observed in tears from eyes with vascularized corneal ulcers (G1) as well as in contralateral tears (G5), compared to normal dogs (G6). High-concentrated EAMH provided a greater decrease in VEGF levels in-vitro compared to low-concentrated EAMH. Conclusion: EAMHs exhibited high concentrations of PEDF in comparison to VEGF and were able to partially decrease VEGF levels in tears of dogs with vascularized ulcers, in-vitro. Our results suggest that VEGF concentration is elevated in tears of dogs with active vascularized ulcerative keratitis in both affected and contralateral eyes compared to that of healthy dogs.

Normal values of b-wave responses of full-field electroretinogram in Lhasa Apso dogs with cataracts according to age / Valores de normalidade das respostas da onda-b do eletrorretinograma de campo total (ERG) em cães da raça Lhasa Apso com catarata de acordo com a faixa etária

Lhasa Apso dogs with immature, mature or hypermature cataracts were divided into four groups according to their age (G1: 1 to 3 years old, G2: 4 to 7 years old, G3: 8 to 11 years old, G4: more than 12 years old). All animals were evaluated under the same sedation protocol to allow the performance of the electroretinogram (ERG) exam to determine normal value of b-wave response of the full-field ERG according to age. Three ERG responses were recorded: rod, maximal and cone responses. The amplitude values and b-wave implicit time of the responses of all groups were compared and analyzed by Kruskal-Wallis test (variance analysis for non-repeated measures), followed by the Dunn post-test (when p<0,05). A significant decrease was observed in maximal responses' amplitude, when comparing the G4 group with G1 and G2. No statistically relevant differences were observed in the b-wave implicit time values between groups. The ERG values are directly influenced by the animal's age. Older patients presented a decrease in the amplitude of the maximal response. The study determined the normal parameters of ERG b-waves for Lhasa Apso dogs with cataract according to their age group.

Cães da raça Lhasa Apso com catarata imatura, madura e hipermadura foram subdivididos em 4 grupos (G1: 1 a 3 anos, G2: 4 a 7 anos, G3: 8 a 11 anos, G4: acima de 12 anos), submetidos ao mesmo protocolo de sedação para a realização do exame de eletrorretinograma (ERG),com o objetivo de determinar o valor de normalidade da resposta da onda-b do ERG de campo total. Três respostas foram obtidas: resposta de bastonetes, máxima resposta e resposta de cones. Os valores da amplitude pico a pico e do tempo de culminação da onda-b dos grupos foram comparados e analisados pelo teste de Kruskal-Wallis (análise de variância por medidas não repetidas), seguido pelo teste de Dunn (quando p<0,05). Quando comparado G4 ao G1 e G2, observou-se diminuição significantiva na amplitude da máxima resposta, sugerindo influência da idade nos parâmetros eletroretinográficos. Não foi observada diferença significativa nos valores obtidos do tempo de culminação em nenhuma das respostas dos quatro grupos analisados. Este estudo determinou os parâmetros normais da onda b no ERG dos cães da raça Lhasa Apso com catarata de acordo com a faixa etária.