p.10
Photoreceptors in the Retina
What is spectral sensitivity?
The relative efficiency of light detection as a function of the wavelength of light.
p.20
Circadian Rhythms and Light Influence
What does the internal circadian body clock synchronize to?
The local daily light-dark pattern.
p.20
Circadian Rhythms and Light Influence
What are humans, like other animals and plants, born to live under?
Exposure to solar radiation.
p.20
Circadian Rhythms and Light Influence
What type of variations do humans have complex physiological responses to?
Daily and seasonal variations of UV, visible, and IR light.
p.12
Photoreceptors in the Retina
What do the cone receptors in the human eye respond to?
A wide range of wavelengths of the visible spectrum.
p.12
Color Blindness and Its Genetics
What causes color blindness?
A fault in the development of one or more sets of retinal cones.
p.4
Photoreceptors in the Retina
What are the names of the four photoreceptor types?
Rods, L-cones, M-cones, and S-cones.
p.4
Photoreceptors in the Retina
How are photoreceptors distributed across the retina?
They are distributed in different areas across the retina.
p.10
Adaptation of the Visual System
What are the three states of sensitivity in the visual system related to?
Different retinal illuminance.
p.12
Color Blindness and Its Genetics
What is color blindness?
The inability or decreased ability to see color or perceive color differences under normal lighting conditions.
p.12
Photoreceptors in the Retina
How many cone photopigments do most human visual systems have?
Three cone photopigments (L-, M-, and S-cones).
p.14
Color Blindness and Its Genetics
What do color blind correction glasses use to improve color distinction?
A filter to cut out overlapping wavelengths.
p.4
Photoreceptors in the Retina
What is a key characteristic of the different photoreceptor types?
They have different spectral sensitivity.
p.19
Circadian Rhythms and Light Influence
How does light impact mood?
It can positively or negatively affect it.
p.28
Health Effects of UV and IR Radiation
What effect does IR exposure have on the skin?
It raises the temperature, which can lead to burns if elevated sufficiently.
p.2
Photoreceptors in the Retina
What happens to light when it reaches the retina?
It is absorbed and converted into signals.
p.4
Photoreceptors in the Retina
What is the function of photoreceptors in the retina?
They convert optical radiation to neural signals.
p.21
Circadian Rhythms and Light Influence
Are circadian rhythms self-sustained?
Yes, but they are adjusted by external cues.
p.28
Health Effects of UV and IR Radiation
What is an example of harmful IR exposure to the eyes?
Looking directly at the sun for a prolonged period.
p.11
Types of Vision: Photopic, Scotopic, and Mesopic
What is mesopic vision?
An intermediate state where both cones and rods are active.
p.25
Circadian Rhythms and Light Influence
What is Bright Light Therapy?
A treatment method that uses bright light to influence mood and behavior.
p.7
Afterimages and Color Perception
What occurs when the eyes are diverted to a white space after an afterimage?
Overstimulated cells send weak signals, causing affected colors to appear muted.
p.7
Afterimages and Color Perception
Why does the brain perceive opposite colors during an afterimage?
Surrounding fresh cells send strong signals, contrasting with the muted signals from overstimulated cells.
p.22
Circadian Rhythms and Light Influence
What effects does melatonin have on the body?
It causes drowsiness and lowers body temperature.
p.15
Effects of Aging on Vision
What is presbyopia?
Difficulty in focusing at near-working distances.
p.28
Health Effects of UV and IR Radiation
What can happen if the temperature of the retina is elevated sufficiently?
It can damage the tissue.
p.15
Effects of Aging on Vision
How does pupil size change with age?
There is a reduction in adaptation ability due to limits in pupil size.
p.5
Photoreceptors in the Retina
What is the primary function of cones?
Responsible for color vision and perceiving fine details.
p.18
Effects of Aging on Vision
What is an example of a media that caused seizures in sensitive individuals?
'Pokémon Shock' from the episode 'Dennō Senshi Porygon'.
p.13
Color Blindness and Its Genetics
What is a challenge when describing colors to blind people?
Finding ways to convey color concepts without visual references.
p.25
Circadian Rhythms and Light Influence
What is Seasonal Affective Disorder (SAD)?
A type of depression related to the time of year, causing serious mood changes with seasonal changes.
p.17
Adaptation of the Visual System
How can excessive brightness contrast contribute to eyestrain?
It creates discomfort and strain on the eyes.
p.10
Adaptation of the Visual System
How does adaptation affect the spectral sensitivity of the visual system?
It changes the spectral sensitivity by activating different combinations of retinal photoreceptors.
p.22
Circadian Rhythms and Light Influence
How does light affect circadian rhythms?
Light entering the eye regulates or modifies the phase and amplitude of the circadian system.
p.31
Health Effects of UV and IR Radiation
What can UV radiation purify?
Air, liquids, and granular materials.
p.19
Circadian Rhythms and Light Influence
How does light affect human biological systems apart from vision?
It affects them positively and negatively.
p.19
Circadian Rhythms and Light Influence
What daily human rhythms are governed by optical radiation?
Daily rhythms, endocrine systems, sleep cycles, and mood.
p.26
Health Effects of UV and IR Radiation
What is photophobia?
Sensitivity to light, often resulting in discomfort.
p.9
Adaptation of the Visual System
What is photochemical adaptation?
Change in sensitivity due to the percentage of unbleached pigment in photoreceptors.
p.17
Adaptation of the Visual System
What is a possible cause of eyestrain related to lighting?
Inadequate lighting level for the task.
p.29
Health Effects of UV and IR Radiation
What is a medical benefit of UV radiation?
It is important for the production of vitamin D in the skin.
p.21
Circadian Rhythms and Light Influence
What are circadian rhythms?
Daily rhythms that repeat approximately every 24 hours, driven by an internal biological clock.
p.28
Health Effects of UV and IR Radiation
What happens to photons when they arrive at the retina due to IR exposure?
Some photons are absorbed in the pigment, increasing its temperature.
p.24
Circadian Rhythms and Light Influence
Who else, besides young people and the elderly, experiences sleep disorders related to circadian rhythms?
Night-shift workers and travelers across several time zones.
p.11
Color Blindness and Its Genetics
What is the perception of color during scotopic vision?
There is no perception of color.
p.15
Effects of Aging on Vision
What is the impact of cell loss in aging eyes?
It leads to reduced visual acuity and reduced contrast sensitivity.
p.17
Adaptation of the Visual System
What effect can lamp flicker have on eyestrain?
It can cause eyestrain even when it is not visible.
p.8
Adaptation of the Visual System
What are the extreme luminance levels in terms of cd/m² that the human visual system can adapt to?
From 10^-6 cd/m² to 10^6 cd/m².
p.31
Health Effects of UV and IR Radiation
Why is UV radiation important for human health?
It can destroy microorganisms that may damage human health.
p.16
Health Effects of UV and IR Radiation
What are some symptoms of eyestrain?
Irritation, inflammation of the eyes and lids, blurring or double vision, headaches, indigestion, giddiness.
p.15
Effects of Aging on Vision
What happens to the lens as it ages?
It becomes yellow, reducing short wavelength radiation reaching the retina.
p.15
Effects of Aging on Vision
What is fluorescence in the context of aging eyes?
Light generation that reduces the quality of the image.
p.9
Adaptation of the Visual System
What is neural adaptation?
Change in sensitivity due to neural processes, fast and operative at moderate light levels.
p.7
Afterimages and Color Perception
What causes an afterimage?
Overstimulation and fatigue of cone cells in the eyes.
p.2
Structure and Function of the Eye
What role does the lens play in the eye?
It focuses the image by changing its shape.
p.3
Structure and Function of the Eye
What does the eye produce?
An image of the external world on a layer of photoreceptive cells in the retina.
p.14
Color Blindness and Its Genetics
What type of color vision do humans have?
Trichromatic color vision.
p.14
Color Blindness and Its Genetics
What issue do people with more overlap between green and red regions face?
Difficulty differentiating certain shades.
p.6
Afterimages and Color Perception
What is a common example of an afterimage?
The bright glow that seems to float before one's eyes after looking into a light source.
p.16
Adaptation of the Visual System
What is eyestrain?
Discomfort resulting from prolonged exposure to certain lighting conditions.
p.5
Photoreceptors in the Retina
Where are cones concentrated in the retina?
In the fovea, a small area on the visual axis of the eye.
p.5
Photoreceptors in the Retina
What colors do S-cones, M-cones, and L-cones absorb?
S-cones absorb blue, M-cones absorb green, and L-cones absorb red.
p.18
Effects of Aging on Vision
What can trigger seizures in individuals with photoepilepsy?
Fluctuating light covering a large area with high percentage modulation.
p.29
Health Effects of UV and IR Radiation
Why is vitamin D important for the human body?
It is required for the absorption of calcium.
p.29
Health Effects of UV and IR Radiation
What conditions can be helped by exposure to sunlight?
Rickets and osteomalacia.
p.6
Afterimages and Color Perception
What happens when we stare at a particular color for too long?
It leads to exhaustion of the cone cells that respond to that color.
p.4
Photoreceptors in the Retina
How many types of photoreceptors are in the retina?
Four types: rods, L-cones, M-cones, and S-cones.
p.31
Health Effects of UV and IR Radiation
What types of microorganisms can UV radiation destroy?
Viruses, bacteria, molds, and yeasts.
p.21
Circadian Rhythms and Light Influence
How do plants exhibit circadian rhythms?
They raise and lower their leaves from day to night.
p.13
Color Blindness and Its Genetics
Why is color blindness more common in males than in females?
Because many genes involved in color vision are on the X chromosome, and males have only one X chromosome while females have two.
p.21
Circadian Rhythms and Light Influence
What adjusts circadian rhythms to the local environment?
External cues, with daylight being the most important.
p.27
Health Effects of UV and IR Radiation
What happens to melanin levels with excessive solar radiation exposure?
The body releases more melanin, darkening the skin color.
p.26
Health Effects of UV and IR Radiation
What does 100% UV protection refer to?
Complete shielding from ultraviolet radiation.
p.9
Adaptation of the Visual System
What happens to the iris in response to changes in retinal illuminance?
The iris constricts and dilates.
p.24
Circadian Rhythms and Light Influence
What is important about the timing of light exposure for treatment?
Using high light levels at appropriate times.
p.25
Circadian Rhythms and Light Influence
How can lighting affect individuals with Alzheimer's disease?
It can influence their abilities and behavior.
p.5
Photoreceptors in the Retina
What type of light do rods require to function?
They require less light and function under low light conditions.
p.20
Circadian Rhythms and Light Influence
What does exposure to light help reset in the human body?
The internal circadian body clock.
p.27
Health Effects of UV and IR Radiation
What are the effects of UV radiation on the skin?
Reddening, sun tan, edema, pain, blistering, peeling, and sunburn.
p.27
Health Effects of UV and IR Radiation
How does melanin protect the body from solar radiation?
By absorbing solar radiation.
p.5
Photoreceptors in the Retina
What are the types of photoreceptive cells in the eye?
Rods and cones (S-cones, M-cones, L-cones).
p.15
Effects of Aging on Vision
What does clouding of the lens refer to?
A decrease in transparency in the lens.
p.25
Circadian Rhythms and Light Influence
What type of therapy is used to treat Seasonal Affective Disorder?
Light therapy with sunlight or bright lights.
p.5
Photoreceptors in the Retina
Where are rods concentrated in the retina?
In the outer edges of the retina.
p.5
Photoreceptors in the Retina
What is the primary function of rods?
Responsible for night vision.
p.22
Circadian Rhythms and Light Influence
What is the human body's response to the light-dark cycle?
It secretes hormones that synchronize the body clock to a 24-hour cycle.
p.26
Health Effects of UV and IR Radiation
What types of electromagnetic radiation affect human health?
UV, visible, and IR spectrum.
p.26
Health Effects of UV and IR Radiation
What are some effects of UV exposure on the eye?
Clouding of cornea, reddening of the eye, tearing, photophobia, twitching of the eyelids, and a feeling of grit in the eye.
p.23
Circadian Rhythms and Light Influence
Why is melatonin important?
It is important for a normal sleep-wake cycle.
p.5
Photoreceptors in the Retina
How many rods are present in the human eye?
Approximately 120 million.
p.9
Adaptation of the Visual System
What happens to pigment during changes in retinal illuminance?
Pigment is bleached and regenerated to re-establish equilibrium.
p.19
Circadian Rhythms and Light Influence
What systems are influenced by optical radiation entering the eye?
Endocrine systems and sleep cycles.
p.27
Health Effects of UV and IR Radiation
What are the long-term effects of frequent UV radiation exposure?
Skin aging and increased risk of certain types of skin cancer.
p.25
Circadian Rhythms and Light Influence
What is the recommended light intensity for effective light therapy?
2,500 – 10,000 lux at the eye.
p.15
Effects of Aging on Vision
What is the trend in retinal disease prevalence with age?
There is an increased prevalence of retinal disease.
