Home and Community Care Digest

Home and Community Care Digest 6(2) May 2007 : 0-0

The quality of light in homes and disability in older persons

Abstract

This study examines the visual ability of community-dwelling older people who have self-care disabilities. Vision was tested under different qualities of light in order to determine whether the brightness of the lighting in the home could improve the visual ability of the participant. The researchers also tested how vision could be improved if present eye conditions were corrected. The results of the study indicate that for the majority of participants, improving the lighting in the home can improve visual ability. The results also highlight the number of older people who could benefit if present eye conditions were improved. Researchers suggest that these improvements will lead to reduced self-care disability.
Background: Vision loss is known to increase with old age. In some cases vision loss is attributable to eye disease, e.g. cataracts or glaucoma. Aging of the lens reduces the amount of light which enters the eye, to the point that the non-diseased eye of a 20 year old receives 6 times more light than that of an 80 year old. This study looks at the relationship between the quality of light in the homes of community dwelling older people, the extent of their natural vision loss, and their self-reported ability to conduct activities of daily living. The aim of the study is to determine: a) the differences in light quality and vision loss among community-dwelling older people; and b) the extent to which improvements in light quality and vision quality reduce disability.

Methods: Participants in this study were community-dwelling Medicare beneficiaries living in New York City who were over the age of 70 and voluntarily agreed to participate. In order to be eligible for the study, participants had to report difficulties with at least one, but no more than three, of the four domains of physical function: upper extremity, lower extremity, instrumental activities of daily living and activities of daily living. The level of disability was determined through self-report. Participants who reported difficulty in either an instrumental activity of daily living or an activity of daily living were considered to have a disability. Vision ability was tested three times. The same measurement tool (reading card) was used to test vision levels; and for each test, the participant was required to identify letters of the alphabet at varying sizes. During the first test, vision was tested under the regular lighting in the participants' home while the participant wore their usual reading correction (e.g. reading glasses). In the second test, participants read the card while a device increased the light around the letters on the tool, which the researchers labeled "standard lighting". The third test determined the visual ability the participant would have if their eye condition was corrected. This test asked participants to read the card while looking through a device that is designed to assess the ability of the eye to see if there were no diseases present. This device improves vision for some individuals with correctable eye disease, including cataracts.

Findings: This study tested the vision of 299 adults between the ages of 70 and 99. The proportion of individuals with 20/20 vision under the regular lighting in their home was 1%, under standard lighting it was 5.4%, and after correcting for eye disease it was 13%. When standard lighting was used to test vision, 63% of participants had improved vision - more than two lines on the letter card. In addition, in 85% of participants their vision improved when viewing the card through the device which corrects for eye disease compared to the test under regular lighting with regular vision correction. This same improvement was present for 60% of participants compared to the standard lighting test. Participants who reported self-care disabilities (16.4%) had significantly poorer visual ability under the regular lighting in their home than participants who did not report self-care disability. The researchers suggest that selfcare disability may improve if lighting in the home improved to standard lighting conditions and if the individuals received treatment for correctable eye conditions.

Conclusions: The results of this study demonstrate that when the lighting in the homes of communitydwelling older people was improved, the majority of participants had improved vision. Additionally, the majority of participants could potentially see better if eye disease was corrected. Improvement of vision may lower the rate of self-care disability rates among community-dwelling older people.

Reference: Albert SM, Bear-Lehman J, Burkhardt A. "Disparities between ambient, standard lighting and retinal acuities in community-dwelling older people: Implications for disability." Journal of the American Geriatrics Society. 2006;54:1713-1718.

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