Summary
This review covers the biology of intrinsically photosensitive retinal ganglion cells (ipRGCs) containing melanopsin, which mediate non-image-forming responses to light including circadian entrainment, pupillary light reflex, and melatonin suppression. Importantly for clinical lighting design, ipRGCs are relatively preserved in certain optic neuropathies, suggesting that non-visual light responses may persist even when pattern vision is compromised.
Key Findings
- ipRGCs containing melanopsin serve as the primary conduit for non-image-forming light responses including circadian photoentrainment and pupillary light reflex.
- Melanopsin-containing ipRGCs are relatively spared in inherited mitochondrial optic neuropathies compared to conventional retinal ganglion cells.
- ipRGCs project primarily to the suprachiasmatic nucleus (SCN), the intergeniculate leaflet, and the olivary pretectal nucleus, mediating distinct non-visual light responses.
Categories
The Science of Light: Reviews the biology of melanopsin-containing ipRGCs, their photoreceptor function, and their role in non-image-forming visual responses.
Sleep & Circadian Health: Describes how ipRGCs drive circadian entrainment and the light-dark cycle regulation of the SCN.
Eye Health & Vision: Notes that melanopsin-containing ipRGCs are relatively spared in inherited mitochondrial optic neuropathies, with implications for preserved non-visual light responses in these conditions.
Author(s)
EE Benarroch
Publication Year
2011
Related Publications
The Science of Light
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- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Melanopsin is required for non-image-forming photic responses in blind mice
Sleep & Circadian Health
- Phototransduction by retinal ganglion cells that set the circadian clock
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- The twoâprocess model of sleep regulation: a reappraisal
- Melanopsin is required for non-image-forming photic responses in blind mice
- Strange vision: ganglion cells as circadian photoreceptors
Eye Health & Vision
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Genetic reactivation of cone photoreceptors restores visual responses in retinitis pigmentosa
- Melanopsin and rodâcone photoreceptors play different roles in mediating pupillary light responses during exposure to continuous light in humans
- Characteristic patterns of dendritic remodeling in early-stage glaucoma: evidence from genetically identified retinal ganglion cell types
- Intrinsically photosensitive melanopsin retinal ganglion cell contributions to the pupillary light reflex and circadian rhythm