UNDERSTANDING THE AGING EYE

The human visual system deteriorates throughout adult life and is considered “young” until it reaches 40 years of age

As the visual system ages:

• Less light reaches the back of the eyes
• Pupils decrease in size
• Lens becomes thicker, so that it absorbs more light

DESIGNING EFFECTIVE LIGHTING SYSTEMS FOR THE ELDERLY

• AMBIENT LIGHT LEVELS: Should be increased by 50% versus those used for younger people. Ambient levels should be at least 300 lux
• TASK LIGHTING: Light levels should be at least 1000 lux on task areas to see fine details
• CONTRAST: The contrast of objects such as stair edges, curbs, ramps, or doorways should be increased by using paint or other techniques
• COLOR PERCEPTION: Can be improved by using high illuminance levels and high-quality fluorescent lamps versus incandescent lamps

SLEEP QUALITY IN THE ELDERLY

Between 40-70% of people over 65 suffer from chronic sleep disturbances

Sleep disturbances result from a disruption of the body’s circadian rhythms

Scientists at Rensselaer Polytechnic Institute’s lighting research center [LRC] have demonstrated that blue light is the most effective at stimulating the circadian system

This light must be combined with the appropriate light intensity, spatial distribution, timing and duration

LRC researchers tested a goggle like device to improve the sleep quality in older adults

A marked increase in daytime lighting levels can counteract the age-dependent losses in retinal light exposure