Abstract
Thirteen retinoschisis males with genotyped XLRS1 gene mutations were examined by electroretinogram (ERG) techniques to determine photoreceptor involvement and ON-pathway and OFF-pathway sites of dysfunction. Parameters Rmax and log S determined by fitting the mathematical model of the activation phase of phototransduction to the scotopic and photopic a-wave responses, were not significantly different from normal. However, the XLRS photopic a-wave amplitudes were significantly lower than normal across all intensities, consistent with defective signaling in the OFF pathway. Long flash (150 ms) ON-OFF photopic responses showed reduced b-wave amplitude but normal d-wave amplitude, giving a reduced b/d ratio of < 1.32 Hz photopic flicker ERG fundamental frequency responses showed reduced amplitude and delayed phase, consistent with abnormal signaling by both the ON- and OFF-pathway components. These results indicate that the XLRS1 protein appears not to affect photoreceptor function directly for most XLRS males, and that ERG signaling abnormalities occur in both the ON- and OFF-pathway components that originate in the proximal retina.
Original language | English (US) |
---|---|
Pages (from-to) | 3931-3942 |
Number of pages | 12 |
Journal | Vision Research |
Volume | 41 |
Issue number | 28 |
DOIs | |
State | Published - 2001 |
Externally published | Yes |
Keywords
- A-wave
- Electroretinogram (ERG)
- Flicker
- Photoreceptor
- Retinoschisis
ASJC Scopus subject areas
- Ophthalmology
- Sensory Systems