The Effect of Natural and Artificial Light via the Eye on the Hormonal and Metabolic Balance of Animal and Man

Abstract

Color change of the plaice and frog, and development of the testes in duck are induced by light stimuli via the eye. Eliminating experiences on the frog (Hollwich) and on the duck (Benoit) showed that these stimuli – beside vision – use a separate way, the so-called ‘energetic portion’ of the visual pathway (Hollwich). In compared studies on blind and on temporarily blind patients involved by cataract in both eyes, we found significant low levels of ACTH and cortisol. The levels normalized after cataract extraction. – Furthermore, we studied the influence of strong artificial illumination (3,500 and 3,200 lx) on healthy persons with considerable and, on the other hand, with minimal difference of their spectral composition to daylight. We found stress-like levels of ACTH and cortisol in the first group. These findings explain the agitated mental and physical behavior of children staying the whole day in school under artificial illumination with strong spectral deviation from daylight. Therefore, to avoid mental and physical alterations, the spectrum of artificial illumination should be largely similar to that of natural light.

The effects of natural light on measures of meat quality and adrenal responses to husbandry stressors in swine

“…These data suggest that natural light has an effect in terms of "basal" adrenal activity. These data are in broad agreement with the data of Hollwich and Dieckhues (1980), who demonstrated lower ACTH and cortisol levels in children exposed to natural lighting. Thus, the evidence appears to favor wavelength composition as the primary factor in differences between cortisol levels in CD samples.…”

“…Hollwich and Dieckhues (1980) found that children exposed to coolwhite fluorescent lighting, compared with either natural or simulated natural light, had significantly elevated plasma levels of ACTH and cortisol. It is possible that a similar situation may also occur in pigs, resulting in higher baseline cortisol concentration in animals raised under artificial light.…”

Stimulatory Effect of Morning Bright Light on Reproductive Hormones and Ovulation: Results of a Controlled Crossover Trial

“…However, contrary to animal findings, there is no solid evidence that melatonin plays a significant role in the modulation of the human reproductive function (summarized in [19]). Light may act directly on the hypothalamic-pituitary-ovarian axis as it might for the hypothalamic-pituitary-adrenal axis [20]. The neuroendocrine mechanism involved in the stimulatory effect of light may be different from those regulating the monthly increase of LH and FSH during the follicular phase.…”

Using visual simulation to evaluate restorative qualities of access to nature in hospital staff break areas

“…Moreover, daylight entering the retina can influence the function of the pituitary gland, which controls hormonal secretions. Melatonin, naturally secreted when there is an absence of daylight, can result in drowsiness, low levels of consciousness, and feelings of depression (Hollwich & Dieckhues, 1980;Ott Biolight Systems Inc., 1997). Exposure to bright daylight, in contrast, can be an effective treatment for depression by controlling the hormonal state and inducing serotonin secretion (Hollwich & Dieckhues, 1980;Golden et al, 2005).…”