Analyze the influence of lighting environment on visual function

Recently, CIE has released a new technical report entitled "Lighting for Older People and People with Visual Impairment in Buildings" (CIE-227), which analyzes the visual environment (such as visual acuity, contrast sensitivity, vision and color vision ) On the office, public places and the elderly and low vision crowd residential and other indoor environment gives some for the elderly and low vision of the crowd lighting design method.

 

When the age of more than 45 years of age, people's eye light scattering gradually increased, spatial contrast sensitivity and retinal illumination gradually weakened, dark adaptation decreased, color vision weakened, people's vision will gradually weaken. According to the World Health Organization (WHO) statistics, more than 288 million people worldwide were damaged in 2017, and as the global population aging problem became increasingly serious (as shown in Figure 1), the social labor force gradually tended to age, And low vision of the crowd lighting design can not be ignored.

 

 

Figure 1 Percentage of aging population in each country (over 65 years old) and future estimated population aging

 

In previous reports, CIE123-1997 describes the impact of the lighting environment on visual functions such as visual acuity, contrast sensitivity, visual field and color vision, and presents some lighting design recommendations for low vision groups; ANSI / IES RP CIE 196: 2011 analyzes the comparative sensitivity (CSF) calculation model for different age groups for lighting design, such as elevators, corridors, bedrooms and bathrooms, and the overall lighting design for older people. Teachers and engineers to provide design for the elderly and visually impaired people.

 

This technical report on the basis of existing research, combined with the current social status quo, the following improvements and improvements:

 

â‘  the elderly age limit from 65 years old to 50 years old, and increased the office and other public places for the elderly and low vision of the crowd lighting design requirements;

 

(2) The influence of visual effects such as illumination level, brightness contrast, disability and discomfort glare and other visual effects on the sensitivity and glare sensitivity of the human eye were systematically analyzed, and the corresponding design recommendations for the elderly and the low vision group were given ;

 

(3) Analyze the design methods of lighting and color in different places in more concrete form.

 

According to the technical report analysis, with the increase of age, although the human eye on the light source and background brightness contrast sensitivity decreased, but the increase in intraocular light scattering will directly increase the size of the light source in the retina, from the unified glare index UGR model Learned that the larger the size of the light source, the higher the glare level, so the higher the age, disability glare and discomfort glare on the human eye visual impact is more obvious. As shown in Figure 2, the same light curtain brightness, in the eyes of the elderly glare was significantly higher than the young people.

 

 

Figure 2 The appearance of the same light curtain emitted by the computer in the eyes of the young (left) and the elderly (right)

 

In addition to visual function, but also has a non-visual function, non-visual effects on the circadian rhythm of the human body has an important impact. The light level, spectrum, light distribution, light frequency and duration of the light source will have an impact on human mood and sleep quality. Therefore, in order to better protect the eyesight and physical health of the elderly and low vision groups, the design of environmental lighting should take into account the impact of lighting on human visual and non-visual effects.

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