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São Paulo, Brazil

Gomes D.,Clinica Vetmasters | Otsuki D.A.,University of Sao Paulo | Lisak R.,Clinica Vetmasters | Safatle A.M.V.,Clinica Vetmasters
Ciencia Rural | Year: 2013

Generalized progressive retinal atrophy (GPRA) is a common disease in Cocker Spaniels dogs characterized by progressive loss of retinal function and disappearance of photoreceptors. The disease is bilateral, hereditary, autosomal recessive, has no sexual predisposition and is frequently associated with cataracts. According to molecular studies the degeneration occurs by a mutation in different genes. In American Cocker Spaniels dogs the disease is observed between three and five years of age and in English Cocker Spaniels between four and eight years old. The clinical signs are: nyctalopia, tapetal hyperreflexia and cataracts. The diagnosis is based on clinical history, ophthalmologic examination and complementary exams such as electroretinography, ocular ultrasound and genetic testing. This article aimed to conduct a review of literature on the generalized progressive retinal atrophy (GPRA) in Cocker Spaniel dogs with cataracts. Source


Electroretinogram (ERG) is an objective and noninvasive diagnostic tool for the evaluation of retinal function, capable to detect early, lesions of the outermost layers in several species of animals. One of its main indications is to evaluate pre-surgical patients for cataract surgery. The determination of normal ERG values is essential if the aim is, by measuring the values; aid the diagnosis of retinal degeneration, despite of the presence of media opacity (cataract). The objective of this study was to standardize the values of electroretinogram responses in Poodle dogs with mature or hypermature cataract, submitted to the same sedation and dark adaptation protocol, using a portable electrodiagnostic system, BPM 200. In all animals, the ophthalmologic examination preceded ERG. Animals were divided into four groups according to age: 1 to 3 years (GI), 4 to 7 years (GII), 8 to 11 years (GIII) and 12 or more years (GIV). Peak-to-peak amplitude (peak of a-wave to peak of b-wave) and b-wave implicit time were measured in rod response and in maximal response and cone response. Dogs with decreased or absent responses were excluded from the study. GI presented decrease in amplitudes of the three responses and increase in b-wave implicit time of rod response when compared with the other groups. B-wave implicit times in maximal response and cone response were practically unaltered in all four groups. It was concluded that there was age- dependent changes in electroretinographic parameters, with decreased amplitudes in rod response, maximal response and cone response. Delay in b-wave implicit time was observed in rod response and unchanged in the two others tested responses of animals subjected to the same ERG protocol. Source

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