As an outline of describing lighting technology that supports social welfare, current movements on universal design, accessible design and so on were mentioned together with the social needs for taking care for them, and pointed out the needs for lighting technology for older persons and person with disabilities. It was also pointed out that survey on the needs of older persons and persons with disabilities as well as the human data of those persons are necessary to make this field progressed in the near future.
It is important to understand the visual characteristics of the elderly for designing lighting environment in aging and aged societies. In the present review, I summarize age-related changes of vision and explained the formulation methods on those. In addition, I introduce optical simulation methods of aged crystalline lens and senile miosis and a color rendering visualization simulator. For the elderly vision simulation, it is necessary to implement a color appearance model of the elderly taking account of "color constancy with aging". Finally, I argue a visibility index function which quantitatively predicts visibility of characters for the elderly.
The following visual functions of low vision were outlined: Contrast sensitivity function (CSF), Color similarity. and minimum legible letter size. In general, data of low vision were widely distributed. The median curve's peak contrast sensitivity is at about 0.2〜0.6cpd, which is much lower than the averaged values of young unimpaired subjects. The span of similarity of colors was broader in low vision patients under both lighting conditions. It was greater under dark conditions. In case of legible letter size, the gothic-type font is apparently more legible than the plain one. In addition, the negative font (white characters on a black background) is more legible than the positive one.
Most documents or web pages, including figures and graphs, are produced in color in order to attract viewers' attention and/or to help them obtain information. However, using color does not necessarily make documents more accessible to all users, especially those with color vision deficiencies. This article summarizes simulation method of color-vision deficiency for color universal design which helps us to detect color combinations in a given image that would confuse color dichromats.
People with low vision walk with their remaining visual capability, and because their eyesight declines prominently during the night time, many walk using streetlights as a guide. Thus, it is effective to deploy streetlights systematically. However, it is difficult to visually indicate changes in walking environment such as staircases or crosswalks. In this research, we discuss how blocks for guiding the visually-impaired can be visually enhanced using LED illuminations to assist movement in such environmental changes.
To colour-deficient drivers, red and yellow traffic signals are indistinguishable. The solution is to mark an "X" on red signals that can be seen at 100m only by colour deficient drivers, while drivers with normal vision cannot see it. This elegant design exhibits the inverse "Ishihara's Test" concept; an ironic phenomenon in which the colour blind show relatively higher luminous efficiency in the shorter range (i.e., blue) than in the longer range (i.e., red) of wavelengths, which means that the similarly observed colour combination of red and red purple will be observed as if strongly contrasted "opaque and dull brown" and "clear blue." Then, the experiment found a specific "X" pictograph that all colour blind persons could observe but that none of the people with normal vision could see from 100m.
Otofuke Komeikan Hospital, located in east Hokkaido, renovated its facilities to improve their identity and to remove the cold feeling of a conventional hospital. In this renovation, only LED light sources are used to achieve energy saving as well as the identity improvement.