Lighting for the elderly: a psychobiological approach to lighting

Effects of Miosis on the Visual Acuity Space under Varying Conditions of Contrast and Ambient Luminance in Presbyopia

Background: Presbyopia is an age-related ocular condition, typically affecting individuals aged over 40 years, characterized by a gradual and irreversible decline in the eye's ability to focus on nearby objects. Correction methods for presbyopia encompass the use of corrective lenses, surgical interventions (corneal or lens based), and, more recently, the FDA-approved topical administration of 1.25% pilocarpine. While prior research has demonstrated the efficacy of daily pilocarpine eye drop application in enhancing near visual acuity by increasing the depth of focus leveraging the pinhole effect, limited knowledge exists regarding its influence on visual acuity under varying conditions of contrast and ambient luminance. Methods: This study aims to investigate the impact of these variables on visual acuity, employing the VA-CAL test, among 11 emmetropic and 11 presbyopic volunteers who reported subjective difficulties with near vision. This study includes evaluations under natural conditions with a pinhole occluder (diameter of 2 mm), and subsequent administration of 1% pilocarpine (Pilomann, Bausch + Lomb, Laval, Canada). Results: The VA-CAL results demonstrate the expected, statistically significant effects of contrast and ambient luminance on visual acuity in both emmetropic and presbyopic volunteers. Furthermore, in emmetropic individuals, the application of pilocarpine resulted in a statistically significant reduction in visual acuity. In contrast, presbyopes did not exhibit statistically significant differences in the visual acuity space under either the pinhole or pilocarpine conditions when compared to natural conditions. Conclusions: The pharmacological treatment of presbyopia with pilocarpine eye drops, intended to enhance near vision, does not adversely affect visual acuity in presbyopes. This suggests that pilocarpine may offer a viable alternative for individuals averse to wearing corrective eyewear.

Aging and Visual Impairment

The incidence of visual impairment greatly increases with age. Diabetic retinopathy, senile cataracts, senile macular degeneration and glaucoma are the leading causes of blindness in elderly persons. Environmental modifications, such as levels of illumination and reduction of glare, can enhance an individual's ability to function in society. The nursing home population needs to pay attention to environmental factors as well as standardization of procedures for vision assessment. Much work is needed to develop programs to properly screen and treat the visual problems in elderly persons.

Effect of correlated colour temperature and illuminance levels on user's visual perception under LED lighting in Taiwan

This study aimed to utilise the characteristics of light-emitting diode (LED) lighting, including the adjustable correlated colour temperature (CCT) and illuminance levels, to evaluate the effects of various CCT and illuminance level combinations on visual perception and their patterns under different lighting conditions. Five white light balances with different CCTs were created together with four levels of illuminance. Based on the patterns of visual perception, when the CCT increased with the illuminance levels, the participants' visual perception changed from dim, boring, and sleepy to intense, vivid, energetic, and bright. As the CCT decreased, the participants gradually perceived the lighting as warm and relaxing. As illuminance levels increased, dim and unpleasant feelings progressively changed to bright and pleasant ones. The study attempted to identify lighting combinations that can respond to different psychological needs and can be used as a guide in the future design of lighting equipment. Practitioner summary: Appropriate lighting conditions could aid individuals in increasing the quality of life. This study conducted an experiment to evaluate the effects of various correlated colour temperature and illuminance level combinations on visual perception by using LED lighting. The results showed the effect of the different lighting combinations on the visual perception of the participants. Abbreviation: LED: light-emitting diode; CCT: correlated colour temperature; K: Kelvin; lx: Lux; CIE: Commission Internationale de l'Eclairage; ANSI: American National Standards Institute.

Seasonal Differences in Light Exposure and the Associations With Health and Well-Being in Older Adults: An Exploratory Study

OBJECTIVE

This article reports summer verses winter seasonal variations across a suite of blue light, illuminance levels and health and well-being indicators.

BACKGROUND

The quality of lighting in care homes has been assessed previously, yet seasonal comparisons and the associations with sleep quality are limited. This exploratory study investigates light exposure in two seasons to determine the changes over time and the associations with health and well-being.

METHODS

In a repeated measures design, 16 older people (aged 72-99 years) living in a care home had their personal light exposure and sleep/wake patterns monitored for 4 days. Cognitive ability, mental well-being, daytime physical activity, and visual function were assessed. Mean light levels at preset times across the day, duration in light exposure over 1,000 lux, and sleep parameters were computed. Statistical investigations included correlations exploring associations and paired means tests to detect the changes between seasons.

RESULTS

The mean morning illuminance level in summer was 466 lux and 65 lux in winter. Duration in bright light over 1,000 lux was 46 min in summer and 3 min in winter. Light measures were significantly higher in summer. There was no statistical difference in sleep quality parameters between seasons, but there were significant difference in daytime physical activity level (i.e., this was higher in summer).

CONCLUSION

The findings indicate low level of light exposures experienced in both seasons, with exposure levels being particularly low in winter. This provides new insights into the limited amount of light older people receive independent of season and the possible impacts on sleep and daytime physical activity level.

Supportive living environments: A first concept of a dwelling designed for older adults with dementia

The vast majority of older adults want to remain living independently at home, with or without a sufficient amount of professional home care, even when overall health is starting to decline. The ageing of society and the increase in the number of very old elders goes together with an increase in the number of people with dementia. About two thirds of the diagnosed people in the Netherlands live at home. Dementia has severe implications to the quality of daily life, in particular to independent functioning. This sets extra demands to living environments. Older adults with dementia and their partners ask for living environments that support independence, compensate for declining vitality, and lower the burden of family care. For this purpose, a first concept of a design for a dementia dwelling is presented in this paper, which incorporates modifications in terms of architecture, interior design, the indoor environment, and technological solutions. These design features were derived from literature search and focus group sessions. Current design guidelines are frequently based on practical experience only, and therefore, more systematic field research should be carried out to find evidence for the various design modifications. Also, it needs to be studied how the design features of the dementia dwelling can be incorporated into the existing housing stock.

Circadian and sleep disturbances in the elderly

The incidence of disturbed sleep is strongly increased in healthy and demented elderly. Age-related alterations in the circadian timing system appear to contribute strongly to these problems. With increasing age, a lack of input to the suprachiasmatic nucleus (SCN), the biological clock of the brain, may accelerate de-activation of neurons involved in the generation of 24-h rhythm or output of this rhythm. This process appears to be reversible, since supplementation of stimuli that impinge on the SCN can re-activate these neurons and ameliorate disturbances in the sleep-wake rhythm.

Age, luminance, and print legibility in homes, offices, and public places

Field studies were conducted in homes, offices, and public places with younger and older adults to determine how legibility performance (in a proofreading and phone book search) changes with age and luminance. Homes and public places generally exhibited much lower than recommended luminance values for reading. Older adults had higher light levels in their homes than did younger adults at reading locations. Older adults performed less quickly than did younger adults on most legibility tasks. Adding light helped younger and older adults equally for most legibility tasks (in homes and public places), though increased luminance differentially improved the performance of older office workers. In response to feedback about low light levels, nearly 60% of building managers in public places indicated in a 6-month follow-up that they had improved lighting or were planning to do so. Actual or potential applications of this work include setting luminance guidelines for adults and identifying barriers to lighting changes.

Optimizing the visibility of displays for older observers

Aging is associated with a variety of decremental visual changes, including reductions in retinal illuminance, color discrimination, static and dynamic acuity, near focus, contrast sensitivity, smooth and saccadic eye movements, visual field, visual search, and the ability to see in and recover from glare. Laboratory research, field studies, and self-report data all indicate that many older persons experience significant difficulty in carrying out tasks that depend on these visual functions. It is also increasingly clear that older observer's performance in finding, extracting, and using visual information can be enhanced significantly by designing task environments to minimize the effects of visual deficits. Recent research indicates that optical simulation of visual loss and contrast sensitivity testing, used in conjunction with image processing, may be very powerful tools for designing displays for the elderly and others with diminished spatial vision. These developments are reviewed, and general guidelines for creating ergonomically correct visual task environments for older observers are offered.

Effects of bright light on mood in normal elderly women

Reduced light appears to be a key factor in seasonal affective disorder (SAD). This study asks whether the reduced levels of light experienced by elderly persons might result in depression and other SAD symptoms, and how normal elderly persons might respond to bright light interventions similar to those used to treat SAD. In interviews with 140 senior citizens, we found virtually no seasonal variation in mood and behavior and very little depressed affect. Seventeen of these seniors who had good mental and physical health, with no major eye problems, participated in a crossover study of the effects of bright light on both positive and negative affect and sleep. Although sleep did not appear to be affected, the bright light intervention tended to make these normal elderly persons feel worse--more irritable, anxious, and agitated. These findings confirm earlier reports that bright light is not beneficial for normal individuals who are unaffected by seasonal changes.

Visual impairment among older people

Visual impairment is the most age-related disability, with older people forming the majority of the visually disabled population. This article re-examines the nature of visual impairment among older people and points to a key role for nurses in identification and intervention.

The clinical importance of environmental lighting to the elderly

1. Nurses need to be aware of the effects of artificial lights on the aged because the aged spend a greater amount of time under these lights than do younger people. 2. Although the aged require more light than younger people to see, bright lights may cause glare. The use of indirect lighting is recommended to reduce problems with glare. 3. The aged see best under artificial lighting that simulates natural sunlight. 4. Nurses who work in institutional settings should be sensitive to the need for individualized light-dark cycles.

Melatonin: a chronobiotic with anti-aging properties?

Recently, it has been reported that melatonin administration extends the lifespan of mice, a finding which supports previous research on the effects of pinealectomy and pineal extract administration. The prolongation of lifespan by melatonin has been interpreted in favour of an upregulation of the immune system as well as due to anti-stress properties of melatonin acting via the brain opioid system. In this paper we offer an alternative explanation of melatonin's anti-aging effect: the circadian pacemaker system has a diminished amplitude with age as indexed by a decrease in circulating melatonin levels. Stability of the circadian system correlates with its amplitude and loss of circadian amplitude produces lability which, in turn, leads to internal temporal disorder. Internal temporal disorder may be a precursor of disease states. Exogenous melatonin increases the amplitude of the circadian pacemaker system by feedback onto that system. The hypothalamic suprachiasmatic nuclei are thought to be the mammalian biological clock in the brain and have high concentrations of melatonin receptors. Therefore, melatonin administration in pharmacological doses may prevent aging symptoms by acting at the level of the circadian pacemaker's amplitude.

Intraoral dental lights: test and evaluation

Performance standards of dental task and ambient lighting systems were presented. Twelve brands of commercial dental lights were tested for compliance with ISO draft specifications. Technical results were presented and recommendations made to assist the dentist in selection of an optimal light system.

Person-environment relationships in adulthood: implications for human factors engineering

Environments for aging and the aged are best designed if human factors engineers incorporate a developmental view of adulthood in their planning. Accordingly, environments for living should be designed to accommodate the transitions between stages of adult life as well as the periods of stability. The optimal human factors interventions involve both psychosocial and physical aspects of the environment and include changing people through psychological intervention. Examples of human factors engineering for aging in perception, learning, and memory, as well as work, leisure, and health, illustrate areas that require successively more complicated plans for intervention.