Isabel Schöllhorn

Rodenstock GmbH · Research and Development

The pupil modulates the amount of light that reaches the retina. Not only luminance but also the spectral distribution defines the pupil size. Previous research has identified steady-state pupil size and melatonin attenuation to be predominantly driven by melanopsin, which is expressed by a unique subgroup of intrinsically photosensitive retinal ga...

Evening exposure to short-wavelength light can affect the circadian clock, sleep and alertness. Intrinsically photosensitive retinal ganglion cells expressing melanopsin are thought to be the primary drivers of these effects. Whether colour-sensitive cones also contribute is unclear. Here, using calibrated silent-substitution changes in light colou...

Background There is no consensus on reporting light characteristics in studies investigating non-visual responses to light. This project aimed to develop a reporting checklist for laboratory-based investigations on the impact of light on non-visual physiology. Methods A four-step modified Delphi process (three questionnaire-based feedback rounds a...

It is well known that variations in light exposure during the day affect light sensitivity in the evening. More daylight reduces sensitivity, and less daylight increases it. On average days, we spend less time outdoors in winter and receive far less light than in summer. Therefore, it could be relevant when collecting research data on the non-image...

Exposure to natural daylight benefits human well-being, alertness, circadian rhythms and sleep. Many workplaces have limited or no access to daylight. Thus, we implemented a light-panel ("Virtual Sky"), which reproduced nature-adapted light scenarios. In a laboratory office environment, three lighting scenarios were presented during the day: two li...

Evening exposure to short-wavelength light can acutely affect the circadian clock located in the suprachiasmatic nuclei, sleep, and alertness. The intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin are thought to be the primary drivers of these effects. Much less is known about the contribution of th...

Evening light-emitting visual displays may disrupt sleep, suppress melatonin and increase alertness. Here, we control melanopic irradiance independent of display luminance and colour, in 72 healthy males 4 h before habitual bedtime and expose each of them to one of four luminance levels (i.e., dim light, smartphone, tablet or computer screen illumi...

Future automotive interior lighting might have the potential to go beyond decorative purposes by influencing alertness, circadian physiology, and sleep. As the available space in the interior of an automobile for lighting applications is limited, understanding the impact of various luminous surface sizes on non-image-forming effects is fundamental...

Evening exposure to electric light can acutely suppress melatonin levels and adversely affect subsequent sleep. We conducted a systematic review with meta-analysis investigating the influence of evening illuminance levels on polysomnographically (PSG)-assessed sleep. We also explored how melanopsin (expressed in melanopic equivalent daylight illumi...

Several studies emphasize the great potential of rhythmic light stimulation to evoke steady-state visual evoked potentials (SSVEPs) measured via electroencephalographic (EEG) recordings as a safe method to modulate brain activity. In the current study, we investigated visual event-related potentials (ERPs) and oscillatory power evoked by perceptibl...

Introduction Light emitted from visual displays can acutely increase alertness, improve cognitive performance and suppress melatonin in the evening. Here we tested the influence of different melanopic irradiance levels emitted by a metameric display setting on alertness, vigilance and salivary melatonin levels. Methods In an ongoing study, 37 heal...

Objective and Background: Decades of research in the field of steady-state visual evoked potentials (SSVEPs) have revealed great potential of rhythmic light stimulation for brain–computer interfaces. Additionally, rhythmic light stimulation provides a non-invasive method for entrainment of oscillatory activity in the brain. Especially effective pro...

Licht ist der wichtigste Zeitgeber für die zirkadianen Rhythmen des Menschen. Es kontrolliert diverse chronobiologische Funktionen, wie etwa den Schlaf-Wach-Rhythmus. Treten bei Nachtarbeit künstliche, phasenverschobene Lichtbedingungen auf, so kann dies zur Desynchronisation der endogenen Rhythmen führen und das Befinden negativ beeinflussen. Um a...

Das visuelle System des Menschen ist ideal an das Tageslicht angepasst; diverse chronobiologische Rhythmen bzw. Funktionen werden vom Tageslicht kontrolliert. Eine Beleuchtung in der Nacht mit erhöhtem Blauanteil ist wegen der Melatoninsuppression und damit einhergehenden möglichen Befindensstörungen (z. B. chronische Erschöpfung, Schlafstörungen,...

We describe ProDesk, an ubiquitous, projection-based touch surface system that extends the screen space of today's desktop computer workplaces to the whole surface of an ordinary office desk, along with highly accurate multi-touch interaction. The objective of this system is to offer users more flexibility on tasks in which lots of complex informat...

In this work, the variation of lighting parameters (illuminance and correlated colour temperature) was used as a prestimulus to investigate effects on cognitive processes. To synchronize the pre-programmed lighting scenarios with the stimulus presentation, a control unit with a short response time was implemented into a LED lighting unit with preci...