PURPOSE Blue light is a high-energy emitting light with a short wavelength in the visible light spectrum. Blue light induces photoreceptor apoptosis and causes age-related macular degeneration or retinitis pigmentosa. In the present study, we investigated the roles of endoplasmic reticulum (ER) stress induced by blue light-emitting diode (LED) light exposure in murine photoreceptor cells. MET...

BACKGROUND Thirty-eight patients with SAD participated in a light visor study addressing two questions. 1. Can the development of a depressive episode be prevented by daily exposure to bright light started before symptom onset in early fall and continued throughout the winter? 2. Does the light have to be visible in order to have beneficial effects? METHODS Three groups participated in the st...

The albino rat retina is severely damaged by exposure to bright light. The degree of damage depends upon the intensity of the exposure and its duration. In the present study, electroretinographic (ERG) responses were measured in rats exposed at different ages during the period of retinal development to 24 hr of bright light and then transferred to darkness for about 2 months. The ERG data indic...

Diminished vitamin D is common among older individuals. Sunlight contributes more to vitamin D synthesis than diet or supplementation. This study examined associations between objectively measured light exposure, vitamin D serum levels, and bone biomarkers in 100 men aged over 60 years. Light exposure was measured in lux via Actigraph monitors for 1 week. Significantly, greater levels of vitami...

PURPOSE To determine the relative contributions of inner and outer retinal photoreception to the pupillary light response. METHODS Wild-type, retinal degenerate (rd/rd), and melanopsin mutant (opn4(-/-)) mice were tested for pupillary light responsiveness by video pupillometry before, during, and after exposure to supersaturating light intensities. Similar lighting protocols were used to prob...

BACKGROUND To investigate whether light exposure was associated with objectively measured physical activity (PA) and sedentary behaviour in young people. METHODS Participants (n=229, 46.7% female) were young people (mean 8.8 years [SD±2.2]) from the borough of Camden, UK. Daily sedentary time, moderate and vigorous PA (MVPA) and light exposure were measured using a tri-axial accelerometer wit...

Exposure to light is a major determinant of sleep timing and hormonal rhythms. The role of retinal cones in regulating circadian physiology remains unclear, however, as most studies have used light exposures that also activate the photopigment melanopsin. Here, we tested the hypothesis that exposure to alternating red light and darkness can enhance circadian resetting responses in humans by rep...

introduction: application of light transmitting posts to restore greatly damaged endodontically treated teeth has been increased. it is suspected that light intensity decreases as it passes throughout different materials. this can reduce the degree of conversion required for adequate bond strength throughout the length of these posts. the objective of this study was to evaluate the amount of li...

This study investigated the effect of ultraviolet type A light (UVA) exposure on the tensile properties of elastomeric chain. UVA light exposure was used as model for artificial aging, simulating prolonged storage of elastomeric chain. Tensile strength (n = 60) was measured after exposing Ormco, Forestadent and 3M chains to UVA light for 0, 2, 3, and 4 weeks. Force decay was measured (n = 60) u...