Vision science: Seeing without seeing

Lok, Corie

doi:10.1038/469284a

Cited by 15 publications

(7 citation statements)

References 9 publications

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“…The use of lowdivergence light from lasers, markedly easier to control (focus, steer and mix) than Lambertian light from LEDs, would enable new systems-level lighting architectures. The use of color-mixed laser light would enable in situ tailoring to human or economic preferences of chromaticity, color rendering quality, or health [15]. Other properties of lasers might also be useful, including: high modulation bandwidth for communication purposes, and polarization control for minimizing glare from reflective surfaces.…”

Section: Introductionmentioning

confidence: 99%

Four-color laser white illuminant demonstrating high color-rendering quality

Neumann¹,

Wierer²,

Davis³

et al. 2011

Opt. Express

204

180

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Solid-state lighting is currently based on light-emitting diodes (LEDs) and phosphors. Solid-state lighting based on lasers would offer significant advantages including high potential efficiencies at high current densities. Light emitted from lasers, however, has a much narrower spectral linewidth than light emitted from LEDs or phosphors. Therefore it is a common belief that white light produced by a set of lasers of different colors would not be of high enough quality for general illumination. We tested this belief experimentally, and found the opposite to be true. This result paves the way for the use of lasers in solid-state lighting.

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Section: Introductionmentioning

confidence: 99%

Four-color laser white illuminant demonstrating high color-rendering quality

Neumann¹,

Wierer²,

Davis³

et al. 2011

Opt. Express

204

180

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“…1A). Light-induced (i.e., photochemical) isomerization of PSB11 to its all-trans isomer (PSBAT) triggers an opsin conformational change that, ultimately, activates the receptor and signaling cascade (8,9). However, similar to invertebrate and in contrast to vertebrate rhodopsins, melanopsins are bistable (10).…”

mentioning

confidence: 99%

Comparison of the isomerization mechanisms of human melanopsin and invertebrate and vertebrate rhodopsins

Rinaldi

Melaccio

Gozem

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Comparative modeling and ab initio multiconfigurational quantum chemistry are combined to investigate the reactivity of the human nonvisual photoreceptor melanopsin. It is found that both the thermal and photochemical isomerization of the melanopsin 11-cis retinal chromophore occur via a space-saving mechanism involving the unidirectional, counterclockwise twisting of the =C11H-C12H= moiety with respect to its Lys340-linked frame as proposed by Warshel for visual pigments [Warshel A (1976) Nature 260 (5553):679-683]. A comparison with the mechanisms documented for vertebrate (bovine) and invertebrate (squid) visual photoreceptors shows that such a mechanism is not affected by the diversity of the three chromophore cavities. Despite such invariance, trajectory computations indicate that although all receptors display less than 100 fs excited state dynamics, human melanopsin decays from the excited state ∼40 fs earlier than bovine rhodopsin. Some diversity is also found in the energy barriers controlling thermal isomerization. Human melanopsin features the highest computed barrier which appears to be ∼2.5 kcal mol −1 higher than that of bovine rhodopsin. When assuming the validity of both the reaction speed/quantum yield correlation discussed by Warshel, Mathies and coworkers [Weiss RM, Warshel A (1979) J Am Chem Soc 101:6131-6133; Schoenlein RW, Peteanu LA, Mathies RA, Shank CV (1991) Science 254(5030):412-415] and of a relationship between thermal isomerization rate and thermal activation of the photocycle, melanopsin turns out to be a highly sensitive pigment consistent with the low number of melanopsincontaining cells found in the retina and with the extraretina location of melanopsin in nonmammalian vertebrates.F or a long time it was assumed that the human retina contains only two types of photoreceptor cells: the rods and cones responsible for dim-light and daylight vision, respectively. However, recent studies have revealed the existence of a small number of intrinsically photosensitive retinal ganglion cells (ipRGCs) that regulate nonvisual photoresponses (1). ipRGCs express an atypical opsin-like protein named melanopsin (2, 3) which plays a role in the regulation of unconscious visual reflexes and in the synchronization of endogenous physiological responses to the dawn/dusk cycle (circadian rhythms) (4, 5).Melanopsins are unique among vertebrate photoreceptors because their amino acid sequence shares greater similarity to invertebrate than vertebrate rhodopsin (i.e., the photoreceptor of rods) (6, 7). Like rhodopsins, melanopsins feature an up-down bundle architecture of seven transmembrane α-helices incorporating the 11-cis isomer of retinal as a covalently bound protonated Schiff base (PSB11 in Fig. 1A). Light-induced (i.e., photochemical) isomerization of PSB11 to its all-trans isomer (PSBAT) triggers an opsin conformational change that, ultimately, activates the receptor and signaling cascade (8, 9). However, similar to invertebrate and in contrast to vertebrate rhodopsins, melanopsins are bistable ...

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“…The ipRGCs are primarily responsible for this NIF function, regulating the circadian system – the cycle that is approximately 24 h in duration and which controls our sleep and waking periods – but are also known to regulate pupil size. The existence of a diurnal cycle was first discovered in 1958 in plankton , but was not thought to exist in humans in a way that is entrained by light until much later .…”

Section: The If and Nif Visual Responsesmentioning

confidence: 99%

A review of the effects of colour and light on non‐image function in humans

2017

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This paper reviews the non-image forming aspect of vision. Developments in the last twenty years have seen the discovery of a fifth class of human visual pigment (melanopsin) in addition to the three classes of photopsins in the cones and rhodopsin in the rods. Melanopsin is found in a small number of retinal ganglion cells which then, in addition to receiving input from the rods and cones, are intrinsically photosensitive. These intrinsically photosensitive retinal ganglion cells send their input primarily to the hypothalamus where they help to regulate the circadian system (daily rhythms of sleeping patterns, body temperature, heart rate etc.). The discovery of the anatomical basis of non-image forming vision has led to a great deal of research into the effects of light on sleep, depression and mood, retinal photodamage, and wellbeing, amongst other topics. Given the recent technological innovations in LED lighting that now give us greater control over our environmental lighting it is timely to review the nonvisual effects of light on humans to inform lighting design in the future.3

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Vision science: Seeing without seeing

Cited by 15 publications

References 9 publications

Four-color laser white illuminant demonstrating high color-rendering quality

Four-color laser white illuminant demonstrating high color-rendering quality

Comparison of the isomerization mechanisms of human melanopsin and invertebrate and vertebrate rhodopsins

A review of the effects of colour and light on non‐image function in humans

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