Lip twitch restraint on rebound tonometry in horses / Contenção com cachimbo na tonometria de rebote em cavalos

ABSTRACT: The purpose of this study was to verify the effect of the upper lip twitch restraint on intraocular pressure (IOP) of healthy horses. In this study, forty five Criollo horses, aged between two to 20 years (male or female) were evaluated with rebound tonometer, with and without upper lip twitch restraint. A previous ophthalmic examination was performed with Schirmer tear test, fluorescein test, slit lamp biomicroscopy and direct ophthalmoscopy in all horses. Only healthy animals with no ocular findings were used. The order of the IOP measurements (with or without twitch) and order of the eye (right or left) were randomized. Three measurements of each eye were made and the mean was calculated. Head position was kept above the heart level and no pressure was made over eyelids. At least 10 minutes passed between the evaluations of the same horse. Measurements were made between 3:30 and 5:30pm to avoid circadian fluctuation of intraocular pressure. Statistical analysis was performed with SAS 9.2 software. A Split plot factorial design was used where horses were considered blocks. The mean intraocular pressure values obtained with lip twitch restraint (34.68±6.47mmHg) were significantly higher (P<0.05) than those obtained without (29.35±4.08mmHg). There was no relevant statistical difference between right and left eyes. The restraint of horses with upper lip twitch increased equine intraocular pressure measured with the rebound tonometry.

RESUMO: O objetivo deste estudo foi avaliar o efeito da contenção pelo cachimbo na aferição da pressão intraocular em equinos hígidos. Neste trabalho, 45 cavalos Crioulos, com idade entre dois e 20 anos, machos ou fêmeas, foram avaliados utilizando tonometria de rebote, com e sem contenção, com cachimbo no lábio superior. Exame oftálmico prévio foi realizado, incluindo Teste Lacrimal de Schirmer, prova da fluoresceína, biomicroscopia com lâmpada de fenda e oftalmoscopia direta em todos os cavalos. Somente animais sadios com olhos hígidos foram utilizados. A ordem das tonometrias (com ou sem cachimbo) e a ordem dos olhos (direito e esquerdo) foram randomizadas. Três aferições de cada olho foram realizadas e a média calculada. A posição da cabeça dos cavalos foi mantida acima do nível do coração e nenhuma pressão foi feita sobre as pálpebras. Ao menos 10 minutos se passaram entre as aferições do mesmo cavalo. As medidas foram realizadas entre as 15h30min e 17h30min do mesmo dia, para evitar flutuações relacionadas ao ritmo circadiano da pressão intraocular. A análise estatística foi realizada com o programa SAS 9.2. Foi realizada análise de variância de parcela subdividida, onde o cavalo foi considerado bloco. A pressão intraocular média obtida com cachimbo (34,68±6,47mmHg) foi significativamente maior (P<0,05) que a obtida sem (29,35±4,08mmHg). Não foi encontrada diferença significativa entre olhos direito e esquerdo. A contenção de equinos com o cachimbo aumentou significativamente a pressão intraocular aferida com tonômetro de rebote.

Comparison of a rebound and an applanation tonometer for measuring intraocular pressure in normal rabbits.

OBJECTIVE: To compare intraocular pressure (IOP) measurements made on healthy adult rabbits without the effect of tranquilizers using the new applanation tonometer, Tono-Pen Avia(®), and the rebound tonometer Tonovet(®). METHODS: Intraocular pressure was measured throughout the day (6:00, 9:00, 12:00, 15:00, and 18:00 h) in 38 adult New Zealand White rabbits (76 eyes). The animals were 20 males and 18 females, with a mean weight of 3.5 kg and an average age of 6 months. A complete ocular exam (including Schirmer tear test, fluorescein staining, slit-lamp biomicroscopy, and direct ophthalmoscopy) was performed on all animals at the beginning of the trial. Rebound tonometry was performed, and after 10 min, anesthetic drops were instilled and applanation tonometry was carried out. IOP values obtained using the two techniques were analyzed statistically. RESULTS: The mean IOP was 9.51 ± 2.62 mmHg with Tonovet(®), and 15.44 ± 2.16 mmHg with the Tono-Pen Avia(®). Significant differences between measurements with the two tonometers were observed (P < 0.001). The linear regression equation describing the relationship between the two tonometers was y = 0.4923x + 10.754 (y = Tonovet(®) and x = Tono-Pen Avia(®)). High IOPs were recorded in the early measurements (6:00), but the average IOPs from both devices were statistically similar throughout the day (P = 0.086). The correlation coefficient was r(2) = 0.357. No significant difference in IOP regarding gender was observed. CONCLUSION: The Tono-Pen Avia(®) recorded higher levels of IOP compared with the Tonovet(®). Early in the day, the IOP of rabbits was higher than later in the day, regardless of the tonometer used.

Scanning electron microscopy of the corneal endothelium of ostrich / Microscopia eletrônica de varredura do endotélio da córnea de avestruz

The aim of this study was to examine the endothelial surface morphology and perform a morphometric analysis of the corneal endothelial cells of ostrich (Struthio camelus) using scanning electron microscopy. Polygonality, mean cell area, cell density and coefficient of variation of mean cell area were analyzed. The normal corneal endothelium consisted of polygonal cells of uniform size and shape with few interdigitations of the cell borders. Microvilli appeared as protusions on the cellular surface. The average cell area was 269±18µm² and the endothelial cell density was 3717±240cells mm-2. The coefficient of variation of the cell area was 0.06, and the percentage of hexagonal cells was 75 percent. The parameters evaluated did not differ significantly between the right and the left eye from the same ostrich. The results of this study showed that the ostrich corneal endothelial cells appear quite similar to those of the other vertebrates.

Objetivou-se examinar a superfície posterior do endotélio corneano e realizar análise morfométrica das células endoteliais da córnea de avestruz (Struthio camelus) valendo-se da microscopia eletrônica de varredura. Avaliaram-se o número de lados, a área celular média, a densidade celular e o coeficiente de variação da área celular. O endotélio corneano de avestruz constitui-se de células poligonais uniformes em tamanho e forma, e com poucas interdigitações das bordas celulares. Visibilizaram-se microvilosidades na superfície celular. A área celular média foi de 269±18µm² e a densidade celular foi de 3717±240 células mm-2. O coeficiente de variação foi de 0,06 e o percentual de células hexagonais de 75 por cento. Não foram observadas diferenças significativas entre os parâmetros avaliados entre os olhos esquerdo e direito. Este estudo demonstrou que o endotélio corneano de avestruz é semelhante ao descrito em outros vertebrados.