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Michael Tan, Clemente Paz-Filgueira, Pablo Barrionuevo, Dingcai Cao; Effect of background melanopsin activation levels on contrast sensitivity mediated by postreceptoral pathways. Journal of Vision 2018;18(10):880. doi: https://doi.org/10.1167/18.10.880.
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© ARVO (1962-2015); The Authors (2016-present)
Introduction: Intrinsically photosensitive retinal ganglion cells (ipRGCs) are sensitive to light through a photopigment called melanopsin. IpRGCs project axons to the lateral geniculate nucleus, suggesting melanopsin activation may contribute to visual perception. Here, we assessed the effect of background melanopsin activation level on contrast sensitivity mediated by the magno- (MC-), parvo- (PC-) and konio-cellular (KC-) pathways. Methods: A Maxwellian-view 5-primary photostimulator that can independently control rods, three types of cones and melanopsin activation in ipRGCs was used to generate square-wave modulations (1, 3, 8 and 16 Hz) targeting the three visual pathways, including L+M+S for the magno-, L/(L+M) for parvo- and S for konio-cellular pathway. The stimulus field was a 10.5°-30° annulus. For each stimulus type, temporal contrast sensitivity was measured 2,000 and 20,000 Td under two background melanopsin activation conditions, "Mel-High" and "Mel-Low", with the "Mel-High" condition having background melanopsin activation 25.6% higher than the "Mel-Low" condition. Results: At 20,000 Td, a higher background melanopsin level decreased contrast sensitivity at most of the test frequencies for the modulation types. At 2,000 Td, however, contrast sensitivity was reduced only at 8 Hz and 16 Hz for the S/(L+M) modulation in the KC-pathway. Conclusions: Background melanopsin activation level can modulate the contrast sensitivity mediated by the MC-, PC- and KC-pathways, and the melanopsin´s modulation effect depended on light levels
Meeting abstract presented at VSS 2018
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