Study On Healthy Lighting Suitable For Reading Behavior Of The Elderly

In recent years,with the rapid development of ageing,more attention has been paid to the health of the elderly.In order to deal with the problem of population ageing,the international community has put forward the development concept of "healthy ageing",which aims to meet the multi-level needs of the elderly in daily life,social communication and self realization to the greatest extent by creating a supportive environment,so as to promote the health of the elderly and improve their quality of life.For the elderly,reading is an important content to enrich their spiritual life,and with the general improvement of their educational level,this demand will be more obvious.Promoting reading and spiritual satisfaction of the elderly plays a positive role in realizing healthy ageing.However,the decline of the visual function and cognitive ability with ageing often interfere with their reading experience.Therefore,it is necessary to make up for the reading impairment caused by age factors by supporting regulatory means.Light is an important factor affecting the reading behavior of the elderly.Light entering the human eye can produce both visual and non-visual biological effects.It not only affects people’s visual performance,but also affects their physiological,psychological,emotional and cognitive functions and so on.Based on this characteristic,the concept of "healthy lighting" was put forward.The core connotation of healthy lighting is people-oriented,which complements the connotation of "healthy ageing".Therefore,it is of great academic and social significance to study the impact of light environment on the reading behavior and physical and mental health of the elderly.At present,there were still few studies on reading lighting for the elderly in China.Therefore,in order to promote the reading activities and physical and mental health of the elderly,this study focused on artificial lighting,and the method of "field research-experimental research-data statistical analysis-weight analysis" was adopted to explore the relationship between lighting parameters and the visual performance,visual comfort,physiological rhythm,mood and subjective comfort of the elderly,and the optimal lighting conditions and design suggestions of lighting parameters suitable for reading and physical and mental health of the elderly were put forward,so as to provide a scientific basis for the formulation of healthy lighting standards and related lighting applications for the elderly.The main research contents and results are as follows:(1)Taking the nursing home in Chongqing as an example,the characteristics of reading behavior of the elderly,their satisfaction with the light environment and lighting status of reading space were analyzed by questionnaire interview and field test.The survey results found that more than 50% of the elderly in nursing homes had a high school education level or above,and 68% of the elderly had the habit of reading.The indoor reading places for the elderly were mainly reading rooms and bedrooms.However,the illumination value of these spaces were far lower than the requirements of the standard,and no local lighting for fine operation was found.Although 77% of the elderly were satisfied with the reading lighting,23% of the elderly were not satisfied,indicating that the reading lighting needs of some elderly people have not been effectively met.In addition,about 40% of the elderly thought that the correlated color temperature(CCT)of light source had an impact on emotion,and more than 70% of the elderly prefer white light with intermediate CCT.This reflects the importance of lighting for the visual performance and psychology of the elderly.(2)Through experimental research,this study explored the effects of lighting on the vision,physiology and psychology of the elderly in terms of reading.Considering the influence of time factor on visual and non-visual effects of lighting,the experimental research was examined from two perspectives: short-term reading(≤10min)and long-term reading(30 min):1)No significant changes in ECG indicators of the elderly were found after short-term exposures,but the subjective alertness under low CCT(3000 K)conditions was significantly lower than that under high CCT(6500 K)conditions.After a short-term(≤10 min)visual task,the subjective visual fatigue of the elderly was not obvious,but the blinking frequency under low illuminance(300 lx)conditions was significantly higher than that under high illuminance(1500 lx)conditions,indicating that low illuminance was more likely to cause visual fatigue than high illuminance.For visual task performance,the effects of lighting parameters were different for different types of tasks.The task efficiency of Alphabet table was not significantly affected by lighting;For Arabic numeral tables,the task efficiency of the elderly under high CCT(6500 K)and high illuminance(1000 ～ 1500 lx)conditions was significantly higher than that under low CCT(3000 K)and low illuminance(300 ～ 750 lx)conditions;For the landolt ring test table,the task efficiency of the elderly under low illuminance(300～ 500 lx)conditions was significantly higher than that under high illuminance(750 ～1000 lx)conditions.For subjective preference,the light at a high illuminance(1000 ～1500 lx)was considered to be brighter than that at a low illuminance(300 lx),but the evaluation of visual clarity,light comfort,light atmosphere and other items were not significantly affected by lighting.2)The physiological indicators such as heart rate,ST interval and systolic blood pressure of the elderly were significantly affected by long-term exposures(30 min),and the changes of physiological indicators under low CCT(3000 K)and intermediate CCT(5000 K)conditions was greater than that under high CCT(6500 K)conditions.In addition,after reading for a long time,the blink frequency under intermediate CCT(5000 K)and high CCT(6500 K)conditions were significantly higher than that under low CCT(3000 K)conditions,and the symptom of "blurred vision" at high CCT(6500K)lighting was more obvious than that at intermediate CCT(5000 K)lighting.Moreover,the results of duration of photopic vision showed that high illuminance(1000lx)was more likely to cause visual fatigue than low illuminance(300 lx).For the Arabic numeral table,the task efficiency at a low CCT(3000 K)was significantly higher than that at a high CCT(6500 K).For subjective preference and mood,the light color satisfaction of the elderly under high illuminance(750 ～ 1500 lx)conditions was significantly higher than that under low illuminance(300 lx)conditions,while the mood under low CCT(3000 K)conditions was significantly more positive than that under high CCT(6500 K)conditions.(3)SPSS 20.0 statistical analysis software was used to analyze the relationship between lighting parameters and different indicators,and the relationship models between heart rate,blood pressure,blink frequency,subjective visual fatigue,mood,subjective preference and illuminance were obtained,which provides a theoretical basis for the study of healthy lighting for the elderly.However,different indicators such as vision,physiology and psychology did not have the same demand for lighting.In order to obtain the optimal lighting conditions suitable for the reading of the elderly,the analytic hierarchy process(AHP)was further used to analyze the weight of different influencing factors and the advantages and disadvantages of lighting conditions.The results showed that the light of 500 lx at 3000 K scored the highest,indicating that this lighting condition was most beneficial to the visual activity and physical and mental health of the elderly;while the light of 300 lx at 6500 K scored the lowest,and was the least dominant.(4)Based on the above research results,the key points of healthy lighting design suitable for the reading behavior of the elderly were proposed.Then,the suggestions of lighting parameters to meet each influencing factor were put forward first from six aspects of subjective comfort,mood,visual comfort,physiological rhythm,subjective alertness,and reading efficiency,and then from the perspective of the comprehensive influence of multiple factors,the recommended values of optimum lighting parameters suitable for reading and physical and mental health of the elderly were put forward.At the same time,other key elements in reading lighting design were also combed and summarized from four aspects: the selection of light source and lamps,the selection of lighting system,lighting quality control and lighting mode selection,so as to provide reference for the healthy lighting design of reading space for the elderly.The innovation of this dissertation mainly includes the following three aspects:(1)The present study systematically explored the relationship between lighting parameters and indicators such as visual performance,physiological parameters,subjective alertness,mood and subjective comfort of the elderly from the perspective of reading needs of the elderly,and put forward a research method of healthy lighting based on reading behavior of the elderly combined with visual and non-visual factors.(2)Based on the healthy lighting evaluation indicators affecting reading of the elderly,the models of light parameters were established to reveal the influence rules of lighting parameters on visual and non-visual factors in the reading of the elderly within a certain range.(3)The recommended values of lighting parameters suitable for reading and physical and mental health of the elderly were put forward.