Comparison of full-field electroretinogram in diabetic and non diabetic dogs with cataracts

Safatle A.M.V., Hvenegaard A.P., Otsuki D., Martins T.L., Kahvegian M., Berezovsky A., Salomao S.R. & Barros P.S.M. 2010. Comparison of full-field electroretinogram in diabetic and non diabetic dogs with cataracts. Pesquisa Veterinaria Brasileira 30(12):1071-1076. Laboratory of Investigation in Comparative Ophthalmology, Veterinary Teaching Hospital, School of Veterinary Medicine, University of Sao Paulo, Av. Prof. Dr. Orlando de Marques de Paiva 87, Bloco 8 superior, Cidade Universitaria, Sao Paulo, SP 05508-270, Brazil. E-mail: angsaf@usp.br Being the commonest ocular disorder, dense cataracts disable fundoscopic examination and the diagnosis of retinal disorders, which dogs may be predisposed. The aim of this study was to compare the electroretinographic responses recorded according to the International Society for Clinical Electrophysiology of Vision human protocol to evaluate retinal function of diabetic and non diabetic dogs, both presenting mature or hypermature cataracts. Full-field electroretinogram was recorded from 66 dogs, with ages varying from 6 to 15 years old allocated into two groups: (1) CG, non diabetic cataractous dogs, and (2) DG, diabetic cataractous dogs. Mean peak-to-peak amplitude (microvolts) and b-wave implicit time (milliseconds) were determined for each of the five standard full-field ERG responses (rod response, maximal response, oscillatory potentials, single-flash cone response and 30 Hz flicker). Comparing CG to DG, ERGs recorded from diabetic dogs presented lower amplitude and prolonged b-wave implicit time in all ERG responses. Prolonged b-wave implicit time was statistically significant (p< 0.05) at 30 Hz flicker (24.0 ms versus 22.4 ms). These data suggests full-field ERG is capable to record sensible alterations, such as flicker's implicit time, being useful to investigate retinal dysfunction in diabetic dogs.