Abstract
Purpose:
We have previously succeeded in recording intrinsically photosensitive ganglion cells (ipRGC) response to light stimuli from human eyes using four-primary illumination system, which modulates stimulus levels to the ipRGC and other cones independently (Fukuda et al. 2010; 2012). The purpose of this study was to investigate the effect of age on the electroretinogram (ERG) from ipRGCs in humans.
Methods:
We used the four-primary illumination system (stimulus duration, 250 ms) to stimulate ipRGCs independently of other photoreceptors using a silent-substitution technique (Fukuda et al. J Physiol Anthropol. 2012). Three elder subjects (age, 54.6±5.7 years) and five younger subjects (23.0±1.7 years) are recruited. The implicit times were measured from stimulus onset and offset to the positive peaks and the amplitudes were measured from the baseline to the positive peaks.
Results:
Two distinct positive peaks were recorded after the onset (on-response) and offset (off-response) for ipRGCs responses in both groups. The implicit times of on- and off-responses were significantly longer in elder group (on-response,97.3±2.2 ms; off-response, 282.3±5.2 ms) than those in younger group (on-response,79.0±6.5 ms; off-response, 279.0±13.4ms; P<0.05). In addition, the amplitudes of on- and off-responses in elder group were significantly lower (on-response,1.5±0.2μV; off-response, 1.5±0.1μV) than those in younger group (on-response, 2.5±1.6μV; off-response,2.9±1.8μV;P<0.05).
Conclusions:
These results suggested that the electrical function of ipRGC is significantly influenced by the age in humans.
Keywords: 413 aging •
531 ganglion cells •
507 electrophysiology: clinical