First Author: M.Kuze JAPAN
Co Author(s): M. Ayaki K. Tsubota T. Morita 0 0 0 0 0 0 0 0 0
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We have previously succeeded in recording intrinsically photosensitive retinal ganglion cell (ipRGC) response to light stimuli from human eyes using four-primary illumination system, which modulates stimulus levels to ipRGCs independently (Fukuda et al. 2010; 2012). The aim of this study was to investigate the effect of age on ipRGCs, which are most sensitive to short-wavelength in spectrum, by using electroretinogram (ERG) in humans.
We used the illumination system consisted with the dome embedded four types of light- emitting diode (LED) in the inner wall and the controller (H8/3052, Renesas Technology, Japan) using a silent-substitution technique (Fukuda et al. J Physiol Anthropol. 2012). ERG electrode (EA-102, Mayo, Japan).
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.
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±13.4; P<0.05). In addition, the amplitudes of on- and off-responses in elder group were significantly lower (on-response,1.5±0.2V; off-response, 1.5±0.1V) than those in younger group (on-response, 2.5±1.6V; off-response,2.9±1.8V;P<0.05).
The electroretinal function of ipRGC in elder subjects is different from the younger subjects in humans. These results suggested that the function of ipRGC is significantly influenced by the age in humans.