24-hr Lighting Schemes for Older Adults and Persons with Low Vision

Transcription

1 24-hr Lighting Schemes for Older Adults and Persons with Low Vision Panel Impacts on Vision Glare, Contrast, Color Mariana G. Figueiro, PhD Associate Professor Lighting Research Center Rensselaer Polytechnic Institute 1

2 Why is light so important? Light reaching the retina can impact Visual system enables us to see Perceptual system strong stimulus for postural control and stability Circadian, neuro-behavioral and neuroendocrine system enables us to maintain synchronization with the solar day 2

3 The retina: The visual system Converts radiant energy into electrical signals for the brain Contains two classic types of photoreceptors: rods and cones Contains one novel photoreceptor: iprcgs 3 Image by Dr. Helga Kolb

4 The perceptual system Postural control involves postural orientation and stability In order to establish/maintain vertical orientation, we use multiple sensory references gravity (vestibular system) the support surface (somatosensory system) the relationship of our body to objects in the environment (visual system) 4 photos.com

5 The circadian system All plants and animals exhibit patterns of behavioral changes over an approximately 24-hour cycle that repeat over successive days these are circadian rhythms circa = about; dies = day 5

6 The circadian system Circadian rhythms are influenced by internal and external factors (zeitgebers or time givers) Circadian rhythms in the absence of time cues are said to be free-running and desynchronized from the solar day Light-dark cycle is the major synchronizer of the circadian rhythms to the solar day 6

7 Light and the aging visual system More light on the task area with darker surrounds for the task area Minimize glare by hiding direct and reflected view of the source and minimizing use of glossy reflections Softer shadows throughout the space; balance illuminance levels in the space Increase contrast and improve color discrimination Importance of each depends upon the person 7

8 Lighting for Older Adults Putting it all together Integrating principles, equipment, and techniques for good visibility and aesthetic appeal (at a reasonable cost) Sponsor: AARP Andrus Foundation

9 Aging perceptual system The dependence on visual information for maintenance of postural stability increases with age due to age-related changes that occur in the vestibular and somatosensory systems 9

10 Light and the aging perceptual system Sponsor: National Institute of Nursing Research 10

11 Light and the aging perceptual system Left/right weight symmetry left right 0.3 (NL) light level (lx) Visual cues have a very strong influence on left/right symmetry Significant main effect (p < 0.05) of door frame tilt 11

12 Light and the aging perceptual system Sway Velocity Significant interaction (p<0.01) between sample times and door frame position 12

13 Aging circadian system Earlier onset of sleepiness, early morning awakening and increased daytime napping (33 % of older people) are common with advanced age Changes of function at molecular level in the SCN Less responsive to light Reduced number of neurons Increased sensitivity to light in the phase advanced portion Less light reaches the back of the eye Sedentary life; dim indoor environments Failure of communication between clock and downstream rhythms 13

14 Light and the aging circadian system AD subjects (study 1) Percentage of time subjects were found asleep AD subjects (n = 4) Perecentage of time subjects were found asleep AD Subjects (n = 4) Percentage of time asleep 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Lighting Conditions Red light Blue light Percentage of time asleep 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 10 PM 12 AM 2 AM 4 AM 6 AM Time Red Blue Blue = 66% asleep Red = 54% asleep p = Figueiro et al.,

15 Light and the aging circadian system AD subjects (study 2) Percentage of time subjects were found asleep AD subjects (n = 3) Percentage of time subjects were found asleep AD subjects (n =3) 100% 100% Perentage of time found asleep 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Lighting Conditions Red light Blue light Percentage of Time Asleep 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 12 AM 2 AM 4 AM 6 AM Time Red light Blue light Product donation: Nichia America Corp Blue = 67% asleep Red = 54% asleep p = Figueiro and Rea, 2005

16 Lighting and the aging circadian system Sponsor: American Institute of Architects Light/Dark Ratio Average ratio Baseline1 After intervention 0 Note: Results include data from 4 subjects who completed the experiment and followed the experimental protocol 16

17 Proposed 24-hr lighting solution 17

18 In summary Light isn t just for vision anymore Light touches every aspect of our lives Much of the information we gather from the environment is through the retina Architects can incorporate scientific findings into their design now Integration (circadian, visual, perceptual, aesthetic) is needed and qualitative solutions (e.g., daylight, high CCT, bright or dim light) aren t good enough 18

19 Thank you! 19