Hereditary retinal degeneration in the Abyssinian cat: developmental studies using clinical electroretinography.
Electroretinography was performed in 10 Abyssinian cats, homozygous for a hereditary retinal degenerative disease but still with an ophthalmoscopically normal retina, and in 11 mixed-breed controls, all between the ages of 8 and 104 weeks. A significant reduction of maximum dark-adapted b-wave amplitude was found in affected kittens as young as 8-16 weeks when compared with controls, although there was no major difference in dark-adapted b-wave threshold or implicit time for the b-wave between affected and controls. For cats 33-104 weeks, similar results were obtained except for the b-wave threshold, which was elevated 2.5 log units in one of the affected cats. No significant difference in 30-Hz cone flicker responses were found between affected and controls at any age studied. In the time period 17-32 weeks affected Abyssinian kittens could not be differentiated from controls by means of the electroretinogram. The significant reduction in scotopic b-wave maximum amplitudes in young affected kittens (8-16 weeks) in conjunction with normal thresholds suggests an early drop-out of rods. It is clear that affected kittens can be differentiated electrophysiologically from controls long before there are ophthalmoscopic signs of retinal disease.
Narfström
K
K
Department of Surgery, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala.
Wilén
M
M
Andersson
B E
BE
D000375:Aging / Q000502:physiology; D000818:Animals; D002371:Cat Diseases / Q000503:physiopathology; D002415:Cats / Q000235:genetics* / Q000254:growth & development; D003623:Dark Adaptation; D004596:Electroretinography; D012162:Retinal Degeneration / Q000503:physiopathology / Q000662:veterinary*; D012684:Sensory Thresholds; D014785:Vision, Ocular