Correlação entre o eletrorretinograma de campo total em fase fotópica e ultrassonografia ocular em modo -b de cães com catarata

Abstract

Any change in lens that results in opacity is called cataract. It is one of the main diseases that cause blindness in dogs. Some factors may trigger its development, such as nutritional and metabolic issues, senility and heredity. Its development stage and etiology are the most common classifications. Besides blindness, the evolution of the disease may lead to inflammations (e.g., uveitis), retinal dislocation and glaucoma. Although the use of eye drops, such as marine cineraria and lanesterol, is under discussion, the only treatment recognized as effective by the ophthalmology councils so far is surgery. The most common technique is facectomy, and it is recommended that ocular ultrasound and full-field electroretinogram (ERG) be performed in order to assess eye bulb health and retinal function, respectively. The present study aimed to verify the relationship between the response obtained by the ERG in its stage of adaptation to the light and the vitreous degeneration perceived after ocular ultrasound. For that, it was evaluated 57 eyes of 31 dogs with cataract, with no preference for age, breed or sex, through a B-mode ocular ultrasound made with an M-turbo Sonosite device and a linear transducer of 6 to 13 mHz, and a full field electroretinogram, photopic phase, with an Neuropack 2 MEB- & 102ª / K device, from Nihon Kohdem, and 1-1000Hz bandpass filter. The most common breed was Poodle, with ages varying from two to 16 years. Fifteen individuals were males and 16 females. Our results showed that 19.29% of the eye bulbs presented zero degree of vitreous degeneration (VD), 35.8% presented one and two degrees of VD, and 10.52% presented three degrees of VD. We found hyalosis in 12.56% of the cases and partial displacement of the retina in 3.5%. We found no relationship between VD and cataracts, neither between the age of the dogs and the degree of VD. Ten eyes showed no trace in ERG and 47 presented attenuated results. Considering the results of the exams together, we did not observe a correlation between the stage of development of the cataract and the ERG response, neither between the opacity positioning and the ERG and between the degree of VD and the ERG.