Morphological and ultrastructural study of the palpebral conjunctiva of healthy domestic cats.

OBJECTIVE: To describe the morphology of the meibomian glands and goblet cells in the palpebral conjunctiva of healthy cats. ANIMALS STUDIED: Five healthy domestic cats without ocular changes that had died from causes unrelated to the study were evaluated. PROCEDURES: Forty samples were collected from upper and lower palpebral conjunctiva and 20 from palpebral fornix region in the nasal corner. The samples were processed for scanning electron microscopy (SEM), transmission electron microscopy (TEM), and histopathology. RESULTS: In the SEM analysis of the palpebral fornix, numerous points of mucous extrusion between the cell junctions were visualized, along with the presence of microvilli in the apical portions with small secretory vesicles. A homogeneous surface was highlighted, formed by the arrangement of cell contours in the form of hexagons. The grouping of goblet cells and their cytoplasmic vesicles filled with homogeneous content was visualized using TEM. Histopathology showed goblet cells interspersed with stratified epithelium accompanied by well-vascularized connective tissue. In the samples stained with hematoxylin and eosin, the meibomian glands, formed by acinar cells and with the presence of individual openings of the ducts in the eyelid margin, were easily visualized in the eyelid margins. CONCLUSIONS: This study describes the ultrastructural form of goblet cells and the morphology of the palpebral conjunctiva of healthy cats by the histopathology of the meibomian glands. This description can serve as a parameter of normality and aid in the detection of morphological alterations in these structures, as well as a parameter for comparison with other animal species.

Comparison of four tonometers in the measurement of intraocular pressure in healthy horses.

BACKGROUND: Measurement of the intraocular pressure (IOP) is a useful diagnostic tool in equine ophthalmology. Handheld tonometers, such as Tonovet and Tonovet Plus (rebound), Tono-Pen AVIA Vet (applanation), and Kowa HA-2 (applanation using the Goldmann methodology) are used to obtain IOP measurements in veterinary medicine. OBJECTIVES: To compare and evaluate the accuracy of four handheld tonometers in measuring IOP using different methodologies in healthy horses. STUDY DESIGN: In vivo experiment and cross-sectional survey of healthy horses. METHODS: Intraocular pressure was measured in 72 eyes of 36 horses. An in vivo study was conducted on sedated horses to compare the real IOP values obtained using manometry versus those obtained using tonometry, and a field study was conducted on unsedated healthy horses with normal eyes to measure the IOP values using different tonometers. RESULTS: In the in vivo study, the mean IOP values using ocular manometry was 24.9 ± 4.0 mmHg (range, 20.0-30.0 mmHg). The mean IOP values using tonometry were: Tonovet, 25.7 ± 5.8 mmHg (range 19.5-33.0 mmHg); Tonovet Plus, 24.8 ± 7.1 mmHg (range 13.2-33.2 mmHg); Tono Pen AVIA Vet, 19.2 ± 4.7 mmHg (range 13.1-26.5 mmHg); and Kowa Ha-2, 24.1 ± 1.2 mmHg (range 22.8-25.8 mmHg). In the field study, the IOP values were: Tonovet, 30.7 ± 5.6 mmHg (range 21.7-38.0 mmHg); Tonovet Plus, 29.6 ± 6.7 mmHg (range 16.2-38.6 mmHg); Tono-Pen AVIA Vet, 27.3 ± 5.8 mmHg (range 14.6-37.1 mmHg); and Kowa HA-2, 23.4 ± 2.2 mmHg (range 20.2-28.7 mmHg). MAIN LIMITATIONS: This study included only healthy horses and a limited number of animals in the in vivo study. CONCLUSIONS: There was a strong correlation between the IOP values and manometry for all tonometers. IOP should be estimated using the same tonometer over time, and the bias of the tonometer used, such as overestimation (rebound tonometer) and underestimation (applanation tonometer), should be acknowledged. A normal reference value for each tonometer should be established in horses.

HISTORIAL: La medición de la presión intraocular (IOP) juega un rol crucial en el diagnóstico de oftalmopatías que pueden llevar a la ceguera en caballos. Los tonómetros portátiles, tales como Tonovet y Tonovet Plus (de rebote), Tono-Pen AVIA Vet (aplanación), and Kowa HA-2 (aplanación usando el método Goldmann), son usados para obtener las mediciones de IOP en medicina veterinaria. OBJETIVOS: Comparar y evaluar la precisión de cuatro tonómetros portátiles para medir IOP usando distintas metodologías en caballos sanos. DISEÑO DEL ESTUDIO: Experimento in vivo y estudio transversal de caballos sanos. MÉTODOS: IOP fue medida en 72 ojos de 36 caballos. Un estudio in vivo fue llevado a cabo en caballos sedados para comparar los valores reales de IOP obtenidos usando manometría versus aquellos obtenidos usando tonometría, y un estudio de campo fue llevado a cabo en caballos sanos no sedados con ojos normales para medir los valores de IOP obtenidos con distintos tonómetros. RESULTADOS: En el estudio in vivo, los valores promedio de IOP usando manometría ocular fueron 24.9 ± 4.0 mmHg (rango, 20.0-30.0 mmHg). Los valores de IOP promedio usando tonometría fueron: Tonovet, 25.7 ± 5.8 mmHg (rango 19.5-33.0 mmHg); Tonovet Plus, 24.8 ± 7.1 mmHg (rango 13.2-33.2 mmHg); Tono Pen AVIA Vet, 19.2 ± 4.7 mmHg (rango 13.1-26.5 mmHg); and Kowa Ha-2, 24.1 ± 1.2 mmHg (rango 22.8-25.8 mmHg). En el estudio de campo, los valores de IOP fueron: Tonovet, 30.7 ± 5.6 mmHg (rango 21.7-38.0 mmHg); Tonovet Plus, 29.6 ± 6.7 mmHg (rango 16.2-38.6 mmHg); Tono-Pen AVIA Vet, 27.3 ± 5.8 mmHg (rango 14.6-37.1 mmHg); and Kowa HA-2, 23.4 ± 2.2 mmHg (rango 20.2-28.7 mmHg). LIMITACIONES PRINCIPALES: Este estudio incluyo solo caballos sanos y un número limitado en el estudio in vivo. CONCLUSIONES: Hubo una fuerte correlación entre los valores de IOP por manometría con todos los tonómetros. IOP debería estimarse usando el mismo tonómetro a través de tiempo, y el sesgo del tonómetro usado, como la sobre estimación (tonómetro de rebote) y la baja estimación (tonómetro por aplanación), debería reconocerse. Valores normales para cada tonómetro deberían establecerse para el caballo.