<HTML> <HEAD> <TITLE>The Effects of Visual Decline on the Daily Activities of Older Adults</TITLE> </HEAD> <BODY BGCOLOR="white"> <H1>The Effects of Visual Decline on the Daily Activities of Older Adults</H1> <P><A HREF="index.html">Back to the List of Topics</A></P> <HR> <H3>Introduction</H3> <P> The scientific community has been (and continues to be) intrigued by the physical changes that occur as we grow older. These changes may be the visible ones, such as the loss of hair, the addition of weight , etc., as well as the changes that are not readily seen, such as the impairment or enhancement of the sense. The sense undergoes the most notable change, and consequential has been the most studied, is vision. The following 4 articles provide evidence for the changes that occur within the visual sensory system as we age and provide information regarding how these changes affect the lives of the aging adult community. </P> <H3>Historical Evidence</H3> <P> During the late 1800s, a British scientist by the name of Sir Francis Galton used his labs in London to collect data regarding the functional changes of adults of different age groups. Galton had collected his data through a series of short experiments that were designed to test perceptual and motor functioning. To test visual capabilities, Galton measured the participants visual acuity by measuring the greatest distance at which a specific type (font) could be read. Also, he tested visual reaction time (the current article does provide the specifics for how Galton tested this). Using the data Galton collected from the roughly 7,500 people between the ages of 12 and 84, Claire Morse conducted an analysis to see if this historical data provided evidence that variability increases with age (variability is used to refer to the differing functional capabilities of adults as time passes). </P> <P> The findings of Ms. Morse indicate that just like today, the visual perception of an individual more than 100 years ago decreases as the person ages. They also experience an increase in reaction time to visual stimuli. However, the results for the analysis of all of Galton's realms of interest for which data was collected were inconclusive in reference to Ms. Morse's original ambition. </P> <H3>Self-Reported Impairment</H3> <P> Through the use of small focus groups, researcher Wendy Rogers and her associates attempted to quantify the specific problems of older adults and how these problems pertain to ADLs and IADLs. In the study five groups of people ages 64-80 and one group of those 80 and above were asked a series of questions regarding what they felt to be major limitations in their lives and how they were dealing with these limitations. The subjects' responses to these questions were recorded during the session. These responses were then categorized based on what they dealt with. The four categories were the locus of the problem, activity classification, difficulty vs. risk, and response to limitations. The locus of the problem category contained 3 sub areas-motor, perceptual, and cognitive functioning. Surprisingly, of the 506 items placed in the locus of the problem category, only a small percentage of the complaints dealt with visual problems. But when visual problems were reported, the most frequently impaired activities were reading and driving. To deal with these visual impairments, many people ceased driving. However, some did continue to drive. Those who continued to drive admitted to increased visual difficulties when driving at night; these difficulties were things such as glare, trouble reading signs and discomfort with faster paces of travel. While the data is not statistically analyzed, it does indicate that older adults recognize that their abilities are not what they once were as well providing a base from which further research can draw upon. </P> <H3>Vision and Driving</H3> <P> Two recent studies have looked at the possible effect of the decreased visual ability of older adults on driving capabilities. Both studies compared the results of older adults to those of younger adults. </P> <P> The first study looked at the visual scanning abilities of adults on a scene intended to simulate driving (Maltz and Shinar, 1999). Using a Schieber's (1989) Complex Visual Reaction Time (CVRT) test picture and photographs taken from the perspective of the driver of a car, Maltz and Shinar conducted a directed visual search test as well as an undirected visual search task. The experiment used a small number of participants, 10, that were placed into one of two age groups, 20-30 or 62-80. All participants report vision of 20/30 or better and none wore glasses. For the directed visual search, the participants were instructed to start at the number 1 and progress through the 14th number. For the undirected visual search, all participants were directed to look at the pictures as if they were the driver, assuming they were in a moving car. They were also told to pay particular attention to anything they felt might be relevant to driving the car safely. The participants were allowed 10 seconds to scan each picture. The data recorded was based on eye movement and duration of fixation on a point. The analyzed results indicated that for both the directed and undirected visual search tasks that there is a great variability in the performance of older adults on visual related tasks. When compared with the younger adults, it was found that the older adults mean search time was significantly higher and more varied. This was found to be true for both types of tasks. Age however, was not found to be a significant factor. </P> <P> The second study was conducted by Donald Kline and associates and examined the effect of blurred vision on older adults vs. younger adults. All subjects in this study reported good visual health and were licensed drivers. The stimuli used were standard road signs-6 yellow and black and 6 black and white. The stimuli were presented through a project that allowed the experimenter to increase the clarity of the stimuli systematically. There were two conditions used, a daylight projection and a nightlight projection. For the nightlight project there was a short dark adaptation period prior to presenting the stimuli. With that exception, the two conditions were identical. The subjects were instructed to attempted to read the stimuli and until they were able to do so the clarity of the image increased. After collecting and analyzing the data, it was found that the mean correction for best clarity for both age groups was almost identical (the level at which clarity varied, but the amount of correction required to make the stimuli clear is what was found to be similar). There were only two effects that proved to be significant, the amount of light present and and interaction of visual acuity with age (older people had poorer acuity). The former result was expected. </P> <H3>Conclusion</H3> <P> It has been found by many researchers through out the past 150 or so years that our sensory abilities decline as we age. This no surprise though, since it more common to find older adults utilizing aids such as glasses and hearing aids. However, until recently there has been little research into how these sensory deficits affect the lives of older adults. Thanks to research such as the final three studies cited above, it can now more clearly been seen how visual decline can affect the ability of older adults to maintain their current life style. </P> <H3>References</H3> <P> Kline, Donald W., Buck, Kimberly, Sell, Yvonne, Bolan, Thomas L., Dewar, & Robert E. (1999). Older Observers' Tolerance of Optical Blur: Age Differences in the Identification of Defocused Text Signs. <I>Human Factors, 41,</I> 356-364 </P> <P> Maltz, Masha & Shinar, David. (1999). Eye Movement or Younger and Older Drivers. <I>Human Factors, 41</I> 15-25. </P> <P> Morse, Claire K. (1999). Age and Variability in Francis Galton's Data. <I>The Journal of Genetic Psychology, 160,</I> 99-104. </P> <P> Rogers, Wendy A., Meyer, Beth, Walker, Neff, & Fisk, Arthur D. (1998). Functional Limitations to Daily Living Tasks in the Aged: A Focus Group Analysis. <I>Human Factors, 40,</I> 111-125. </P>  <HR> <P><I>Contributed by Peter Wright, February 18, 2006.</I></P> <P><A HREF="index.html">Back to the List of Topics</A></P> </BODY> </HTML>