Estudo comparativo das estruturas do segmento anterior de olhos de cães com catarata, portadores e não portadores de Diabetes mellitus, avaliadas por biomicroscopia ultra-sônica / Comparison of anterior ocular segment structures in dogs with diabetic or no diabetic cataract, by ultrasound biomicroscopy

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Cataracts is the opacity of the lens or its capsule and represent the leading cause of blindness in dogs. The most common cause of cataract in dogs is a result of inherited alteration of the lens protein metabolism, metabolic alterations caused by Diabetes mellitus (DM) are the second most common cause. This is one of the most prevalent endocrinopathy in dogs and results from an absolute or relative deficiency of insulin. It changes the osmotic balance inside the lens causing bilateral, symmetric and acute cataracts, which the dog is particularly susceptible to. Ultrasound biomicroscopy (UBM) is a high-frequency (50MHz) ultrasonographic method that produces B mode images of microscopic quality. With a 37µm image axial resolution, which is ten times higher than conventional ultrasound, and penetration restricted to about 5mm, it comprises an adequate method for the examination of structures of the ocular anterior segment, even in cases of opacities. The cornea, the anterior chamber and the iridocorneal angle can be real time evaluated. The objective of this study was, by means of UBM use, to compare the anterior segment structures of the canine eyes, both with diabetic and non-diabetic cataract, in order to detect changes caused by DM, bearing in mind the peculiarities of diabetic cataract in dogs. The parameters evaluated were: cornea thickness, anterior chambers depth, increased cellularity inside the anterior chamber, and iridocorneal angle measurement. Eighty-seven eyes of 47 animals of the canine family (canis familiaris) were examined. Nineteen were males and 28 females of several breeds, from 2 to 14 years of age, divided into three groups: control- without any ocular alteration (GCO), diabetic (GDM), and non-diabetic cataract (GCAT). The results showed that the diabetic group presented a statistically significant higher cornea thickness than the other groups. The control group showed deeper anterior chambers and also a statistically significant difference between GCO and GCAT. When the iridocorneal angle measurements were analyzed, it was found that there were no statistically significant differences between the three groups. The control group showed no punctiform echoes - those are suggestive of the increase in cellularity in the anterior chamber these echoes, however, were found in 34,2% of the dogs with non-diabetic cataract and in 29% of the diabetic ones. There is, therefore, a statistically meaningful difference between the CGO and the other two groups (GCTA and GDM). Based on theses results, we can conclude that: the eyes of diabetic dogs with cataract showed a central cornea higher thickness compared to the eyes of dogs with cataract of different etiologies, and to dogs with normal eyes; there is a decrease of the anterior chamber depth in the eyes of dogs with cataract compared to normal eyes, there is no significant difference between the iridocorneal angle measurement in the eyes of dogs with cataract, diabetic or not, and normal dogs.

ASSUNTO(S)

diabetes mellitus dogs biomicroscopia ultra-sônica ultrasound biomicroscopy catarata cataract diabetes mellitus cães

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