LWH Tenta
Which photometric quantity is used to quantify the amount of light emitted or reflected per unit area in a specific direction?
Luminance
Which type of electromagnetic radiation is excluded from the definition of daylight?
Ultraviolet radiation
What is the primary function of the macula in the human retina?
Producing sharp vision
Which vision state involves the activity of both cone and rod photoreceptors?
Mesopic vision
What is the primary cause of floaters in the human eye?
Aging-related changes in the vitreous humour
What is the primary function of the intrinsically photosensitive Retinal Ganglion Cells (ipRGC) in the human eye?
Control pupil size and sleep
What is the term for the continuous adjustment of the human eye to a wide range of light levels,allowing it to function in both very dark and very bright conditions?
Adaptation
What is the significance of circadian rhythms in humans?
Influences sleep, physiology, and hormonal secretion
What can disrupt circadian functioning during night work?
Night-time exposure to electric light
What is the relationship between ipRGCs and mood regulation by light?
Mood regulation involves ipRGCs projecting to the amygdala
What is the potential role of ipRGCs in visual tasks?
Brightness detection
What is the main purpose of chronotherapy?
Combine light exposure with intentional sleep deprivation
Which disorder is often related to mood problems during the winter and is discussed in the context of differences in daylight hours?
Seasonal Affective Disorder
What is the primary challenge faced by shift workers concerning light exposure?
Lack of exposure to natural light
How does the human eye change with age?
The lens becomes less transparent and yellowish
What is integrative lighting design focused on?
Stimulation of ipRGC-induced effects and consideration of visual and beyond visual factors
What does disability glare refer to?
Disabled visual system due to scattered light forming a luminous veil
Which instrument is used to collect input for the CIE S026 Toolbox and generate a mEDI-value?
A melanoptimeter
What is (according to Brown et al., 2022) the recommended minimum melanopic EDI (mEDI)
exposure level during daytime?
250 lx
What does the quantity of 'correlated colour temperature' measure in lighting?
The variation in spectral content of electric lighting
The macula is the centre portion of the retina that produces sharp vision, and a small pit inside the macula has the sharpest vision. What is the name of the pit (indicated with X)?
Fovea
What is a stimulus?
A detectable change in the environment which occurs according to a standard pattern.
According to Souman et al. (2018), what was the key difference between two light sources that appeared visually the same?
Spectral power distribution
Which type of light-involved treatment makes use of a ‘wake-up light’ device that mimics the rise of the sun?
Dawn simulation
What wavelength range is used for light treatment of babies with high bilirubin levels?
390 to 530 nm
According to the CIE definition, what does integrative lighting include?
Lighting specifically intended to integrate visual and beyond-visual effects
Night workers generally (if not always) work at night. In contrast, shift workers periodically work at night, which is interchanged with periods where they work during regular daytime hours or in the early morning or evening. Why is working at night sometimes called 'the graveyard shift'?
Due to the adverse health effects associated with night work.
Brown et al. (2020) recommend that, at least three hours before bedtime, the light levels should decrease to m-EDI of 10 lux, again measured at eye level when sitting (~1.20m). The light must preferably be depleted of short wavelengths. However, there may be a conflict regarding recommendations for visual effects and effects beyond vision. What may be the reason for this conflict?
m-EDI levels of 10 lux are not sufficient for most visual tasks.
The International Lighting Organisation CIE has included the term 'integrative lighting' in their lighting vocabulary. The CIE definition says integrative lighting includes …
…lighting specifically intended to integrate visual and non-visual effects, producing physiological and psychological effects on humans reflected in scientific evidence.
The prevalence of insomnia increases with age, and prevalence rates can go up to more than 30% for people over 65 years. Sleep problems may occur due to circadian dysfunction, especially for older people, who often experience a forward shift combined with an advanced
sleep phase. How much more light does a 65-year-old person need compared to a 25-year-old to reach the same beyond visual effects?
Three times as much
Many of the light effects on human health and well-being change over (life) time as the human physiological and psychological systems change (ageing). What is the range of pupil diameter for young people?
2 to 8 mm
The spectrally tuning method can be used to study the functioning and interaction of all five
photoreceptors specifically. Tuned spectra can be used directly by a light source or incorporated in manipulated images, but either application uses the concept of metamerism. What is metamerism?
The phenomenon where two colours look the same under one lighting condition but different under another.
Humans must (re)set their circadian clocks daily to stay synchronised with the Earth’s 24-hour rotation. Effects of light on circadian rhythms are often expressed as phase-shifting effects. What effect does bright light exposure in the evening generally have on the circadian phase?
It delays the circadian phase.
One of the main functions of the ipRGCs is to orchestrate the biological rhythm, also known as the circadian rhythm. What happens to most individuals' sleep rhythm if their circadian rhythm runs freely without environmental cues?
They (start to) sleep later and later.
Glare is an extreme form of non-uniformity (large contrast) that usually occurs instantly. When exposed to a very high luminance (in the visual field), a typical reaction of humans is to blink, look away, or protect their eyes. Three glare types are most important for lighting designers: disability glare, discomfort glare, and overhead glare. What is disability glare?
A phenomenon that occurs when scattered light in the eye forms a luminous veil over the retinal image.
Humans need light to perceive the world around them and perform tasks, and their eyes enable humans to extract the information required for both. The performance of a complete task is called task performance, but when focussing on just the performance of the visual component of the task, we talk about visual performance. How we see and perceive the world is reasonably well understood nowadays. Research has produced replicated, predictive models, like the Relative Visual Performance model (Rea and Ouellette, 1991). What does the Relative Visual Performance model predict?
The effects of light amount on visual performance in foveal tasks.
The human eye is sphere-shaped with a diameter of circa 24 mm. The pupil is located in the
middle of the cornea, which can vary in size using two sets of muscles. What is the function of the pupil in the eye?
It regulates the amount of light entering the retina.
Two luminaires project their light on a wall. The Figure shows their two different spectral power distributions. These two visual stimuli can have the same ‘white perception’ by having an equal…
… correlated colour temperature.
The CIE spectral luminous efficiency function, V(λ), represents the relative sensitivity of the human eye under photopic (daylight) vision conditions.
What does the V(λ) curve primarily reflect?
The response of long (L) and medium (M) wavelength cones.
Daylight is natural light from the sun and artificial light is created using flames or electricity.
What is one of the primary reasons daylight is preferred over artificial light?
It offers natural variability and environmental stimulation.
Which type of glare is visual discomfort caused by light sources located outside the human visual field above a person's head?
Overhead glare
What is the main focus of dynamic lighting output systems?
Providing dynamic solutions in spectral, spatial, and temporal lighting