Relationship between Daytime Sleepiness and Intrinsically Photosensitive Retinal Ganglion Cells in Glaucomatous Disease

Table 1

Photometric measures for different photoreceptors’ inputs to circadian and neurophysiological light responses in humans [2].

Photoreceptor	Photopigment	Spectral sensitivity function	Unit of measure
Short-wavelength (S) cones	S-cone photopsin (cyanolabe)	Cyanolabe response function (λ)	Cyanopic illuminance (cyanopic-lux)
Medium-wavelength (M) cones	M-cone photopsin (chlorolabe)	Chlorolabe response function (λ)	Chlorolabe illuminance (chloropic-lux)
Long-wavelength (L) cones	L-cone photopsin (erythrolabe)	Erythrolabe response function (λ)	Erythrolabe illuminance (erythropic-lux)
ipRGCs (intrinsic photosensitivity)	Melanopsin	Melanopsin response function (λ)	Melanopsin illuminance (melanopic-lux)
Rods	Rod opsin	Rod opsin response function (λ)	Rhodopic illuminance (rhodopic-lux)

a = each unit of measure (Ea, where a specifies the retinal photopigment) is derived by convoluting the spectral power distribution of incident light (Eel) with the relevant spectral sensitivity function, which in turn is defined by the photopigment spectral sensitivity adjusted for prereceptoral filtering in a standard observer (Na(l); see the online reference (http://www.cie.co.at/index.php?i_ca_id=983) [28] for full functions and a detailed description of their derivation) according to the equation Ea = 72 983.25 R Eel(l) Na(l) dl. Species-specific variants of the spectral sensitivity functions may be required for nonhuman applications to account for differences in prereceptoral filtering and photopigment spectral sensitivity [2].