Avaliação morfológica da glândula de meibômio e conjuntiva palpebrais e comparação entre tonômetros portáteis na mensuração da pressão intraocular em gatos domésticos

Abstract

The objectives of these studies were: 1st) to morphologically describe the meibomian glands and goblet cells of the palpebral conjunctiva; and 2nd) to compare the performance of four tonometers of three different methodologies (rebound, applanation and applanation with Goldmann's methodology), as well as the tolerance to use by domestic cats, in addition to establishing reference values of intraocular pressure (IOP) with the tonometers Tono-Pen Avia Vet and Tonovet Plus in animals without ocular changes. In the 1st study: 60 samples of the palpebral conjunctiva and palpebral fornix region by scanning electron microscopy (SEM) and histopathology from 10 eyelids of 5 cats (3 males and 2 females; 2-120 months; 0.7-4, 3 kg); and in the 2nd the IOP of 108 healthy eyes from 55 cats (28 males and 27 females) without signs of ocular disease by ex vivo, in vivo and clinical evaluations. Eyelid histopathology identified meibomian glands, formed by acinar cells and the presence of individual openings in the eyelid margin; in the fornix conjunctiva goblet cells were observed interspersed with a stratified epithelium accompanied by vascularized connective tissue. SEM analysis demonstrated a conjunctival epithelium with a homogeneous hexagonal surface, with numerous points of mucosal extrusion and the presence of microvilli in the apical portions with small secretory vesicles. The ultrastructural shape of the goblet cells and meibomian glands of the palpebral conjunctiva of cats described for the first time will serve as a parameter for the evaluation of morphological alterations in these structures, as well as a parameter for comparison with other animal species. In the 2nd study: Ex vivo tonometry determined r² values for Tonovet (0.923), Tonovet Plus (0.925), Tono-Pen Avia Vet (0.877) and Kowa HA-2 (0.901). The IOP values in mmHg in the in vivo evaluation were: manometer (16.1±2.7), Tonovet (21.1±3.6), Tonovet Plus (19.7±7.2), Tono-Pen Avia Vet (17.6±7.9) and Kowa HA-2 (16.8±2.0). The three IOP assessment methodologies showed high accurate correlation coefficients, with Kowa HA-2 being the most accurate tonometer, and Tonovet being the most tolerated by cats. In clinical routine, the highest IOP values were measured with the Tonovet and the lowest with the Kowa HA-2, which reinforces the need for a table of IOP reference values for cats for each of these tonometers. The reference values established by the clinical evaluation of Tonovet Plus and Tono-Pen Avia Vet were 16.9±1.2 and 16.2±1.1 mmHg, respectively.