Documenta Ophthalmologica

, Volume 97, Issue 1, pp 9–21

Cone positive off-response in normal and dystrophic cats

  • Björn Ekesten
  • Kristina Narfström

DOI: 10.1023/A:1001817228569

Cite this article as:
Ekesten, B. & Narfström, K. Doc Ophthalmol (1998) 97: 9. doi:10.1023/A:1001817228569


Light-adapted cone ERG in response to white stimuli with long duration (200 ms) was studied in seven normal cats and six cats with early to moderate, inherited retinal dystrophy. The stimuli typically elicited an ERG consisting of an a- and b-wave in response to light onset, whereas light-offset was followed by a cornea-positive d-wave and subsequent negative dip and occasionally a second positive peak in both normal and dystrophic cats, although b- and d- waves had less distinct peaks in cats with moderately advanced retinal dystrophy. Linear regression models indicated a positive correlation between d-wave amplitude and stimulus luminance, whereas a negative correlation was found between amplitude and background light luminance in normal cats. The d-wave implicit time was independent of both stimulus and background light luminance in normal cats. The d-wave amplitude was not significantly different in dystrophic cats, whereas the implicit time was increased when affected cats were compared to normal cats. The significant increase in implicit time in dystrophic cats could not be explained with a reduced sensitivity of the off-pathway to background or stimulus light. This is supported by the finding that d-wave amplitude was not significantly altered in early to moderately advanced dystrophic cats.

ERGretinal dystrophycatsconesoff-responsed-wave

Copyright information

© Kluwer Academic Publishers 1999

Authors and Affiliations

  • Björn Ekesten
    • 1
  • Kristina Narfström
    • 1
  1. 1.Faculty of Veterinary MedicineSwedish University of Agricultural SciencesUppsalaSweden