Aging of non-visual spectral sensitivity to light in humans: compensatory mechanisms?
The deterioration of sleep in the older population is a prevalent feature that contributes to a decrease in quality of life. Inappropriate entrainment of the circadian clock by light is considered to contribute to the alteration of sleep structure and circadian rhythms in the elderly. The present study investigates the effects of aging on non-visual spectral sensitivity to light and tests the hypothesis that circadian disturbances are related to a decreased light transmittance. In a within-subject design, eight aged and five young subjects were exposed at night to 60 minute monochromatic light stimulations at 9 different wavelengths (420-620 nm). Individual sensitivity spectra were derived from measures of melatonin suppression. Lens density was assessed using a validated psychophysical technique. Although lens transmittance was decreased for short wavelength light in the older participants, melatonin suppression was not reduced. Peak of non-visual sensitivity was, however, shifted to longer wavelengths in the aged participants (494 nm) compared to young (484 nm). Our results indicate that increased lens filtering does not necessarily lead to a decreased non-visual sensitivity to light. The lack of age-related decrease in non-visual sensitivity to light may involve as yet undefined adaptive mechanisms.
Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France ; University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France.
Raymond P
RP
Najjar
Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France ; University Joseph Fourier Grenoble 1, Grenoble, France ; Department of Ophthalmology, CHU Grenoble, Grenoble, France.
Christophe
C
Chiquet
Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France ; University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France.
Petteri
P
Teikari
Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France ; Department of Ophthalmology, CHU de Lyon Hôpital Edouard Herriot, Lyon, France.
Pierre-Loïc
PL
Cornut
Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France ; Center of Biology, Hormone Laboratory, Bron, France.
Bruno
B
Claustrat
Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France ; Department of Ophtalmology, Hôpital de la Croix-Rousse, Lyon, France.
Philippe
P
Denis
Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France ; University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France.
Howard M
HM
Cooper
Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France ; University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France.
Claude
C
Gronfier
D000328:Adult; D000375:Aging; D057906:Circadian Clocks; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D007908:Lens, Crystalline / Q000502:physiology; D008027:Light; D008297:Male; D008550:Melatonin / Q000097:blood; D008875:Middle Aged; D012890:Sleep; D055815:Young Adult
D008550:Melatonin