Problems With Vision Associated With Limitations or

Journal of Gerontology: SOCIAL SCIENCES 2004, Vol. 59B, No. 5, S281–S286

Copyright 2004 by The Gerontological Society of America

Problems With Vision Associated With Limitations or Avoidance of Driving in Older Populations William A. Satariano,1 Kara E. MacLeod,2 Theodore E. Cohn,3 and David R. Ragland2 1 School of Public Health, University of California Traffic Safety Center, and 3 Departments of Bioengineering and School of Optometry, University of California at Berkeley. 2

Methods. Data for this study (N ¼ 1,840) were obtained from participants in a community-based study of aging and physical performance in people age 55 or older in the city of Sonoma, California. Each of 16 visual conditions was assessed for impact on reported driving limitation due to eyesight by calculating a ‘‘risk’’ ratio. Then, prevalence of the condition was combined with the ratio to generate an attributable risk for that condition for vision-related limitations in driving. Results. Each condition was significantly associated with reported limitations in driving due to eyesight. ‘‘Avoiding physical activity due to vision’’ (ratio ¼ 3.4) and ‘‘trouble seeing steps up/down stairs’’ (ratio ¼ 2.9) had the strongest association. However, ‘‘glasses/contacts required for driving’’ and ‘‘trouble with glare from sun/lights’’ had the highest attributable risks (35.8 and 29.4). Discussion. The risk ratio is relevant for evaluating individuals; the attributable risk is relevant to planning countermeasures in populations. Addressing specific problems related to vision should substantially reduce driving limitations due to eyesight.

A

MONG older adults, increased age is associated with reduced and modified driving behavior (Ball, Owsley, Stalvey, Roenker, Sloane, & Graves, 1998; Gilhotra, Mitchell, Ivers, & Cummings, 2001; McGwin, Chapman, & Owsley, 2000; Stewart, Moore, & Marks, 1993; West et al., 1997). There is also evidence that women are more likely to stop driving (Campbell, Bush, & Hale, 1993; Stewart et al., 1993) and that reductions in driving are associated with greater depressive symptoms (Fonda, Wallace, & Herzog, 2001; Marottoli et al., 1997). Problems with vision represent one of the leading chronic conditions associated with reduction in or cessation of driving. Vision difficulties have been assessed in a variety of ways that include diagnosed conditions and performance on visual tests. Older drivers with cataracts and other vision difficulties are more likely to restrict their own driving and to be involved in motor vehicle crashes (Dellinger, Sehgal, Sleet, & BarrettConnor, 2001; Lyman, McGwin, & Sims, 2001; Owsley, Stalvey, Wells, & Sloane, 1999; Owsley, Stalvey, Wells, Sloane, & McGwin, 2001). Reduced performance on standardized visual assessments is also associated with a reduction in driving in older adults (Ball et al., 1998; Gallo, Rebok, & Lesikar, 1999; Gilhotra et al., 2001; Marottoli & Richardson, 1998; McGwin, Sims, Pulley, & Roseman, 2000; Sims, Owsley, Allman, Ball, & Smoot, 1998; Stutts, 1998). There is less research on self-reported vision problems or symptoms associated with limitations or avoidance of driving among older drivers (Dellinger et al., 2001; West, Gildengorin, Haegerstrom-Portnoy, Lott, Schneck, & Brabyn, 2003). A better understanding of the barriers to driving associated with

visual deficiencies experienced by older drivers is needed. This would demonstrate the extent to which a limitation or cessation of driving is due to a loss of confidence in the ability to drive and, if so, the extent to which problems with vision contribute to a loss of confidence. Moreover, research in this area should contribute to the development of strategies to extend safe driving years for older adults. In a previous study of older adults in Sonoma, California, current drivers were much more likely to identify problems with eyesight as a reason for limiting their driving than any other medical condition (Ragland, Satariano, & MacLeod, 2004). The current report expands on that study, examining the role of (a) disease processes affecting vision, (b) reported troubles with vision, (c) physical symptoms affecting the eyes, and (d) objective vision tests in reporting limitations to driving because of vision.

METHODS

Subjects The Study of Physical Performance and Age-Related Changes in Sonomans (SPPARCS) is a community-based longitudinal study of age-related changes in physical functioning, physical activity, and fitness among people age 55 and older that reside in and near the city of Sonoma, California. A community-based census identified 3,057 eligible individuals, of whom 68.4% (2,085) agreed to participate in the study. The sample was enrolled between May 1993 and December 1994 and included 1,243 women and 842 men; the median age was 70 years with ages ranging from 55 to 97 years.

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Objectives. This report examines the role of (a) disease processes affecting vision, (b) reported troubles with vision, (c) physical symptoms affecting the eyes, and (d) objective measures in reported driving limitation due to problems with eyesight among older drivers.

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Reasons for Limiting or Avoiding Driving Participants also reported driving limitation for a series of 14 common medical reasons (including a physician’s recommendation and a family member’s recommendation) and 7 common nonmedical reasons. Driver limitation or avoidance was asked in the following way: ‘‘Do you currently limit or avoid any of your driving (either before or after dark) for any of the following reasons?’’ The participant could respond by indicating ‘‘yes,’’ ‘‘no,’’ or ‘‘don’t know’’ to each of 21 specific reasons (14 medical and 7 nonmedical; see Appendix.)

Vision Assessments, Conditions, and Symptoms Subjects indicated if use of corrective lenses was required for driving. Visual acuity was measured using the Smith– Kettlewell Institute Low Luminance (SKILL) Card. The score from the SKILL Card Test, which is dichotomous (i.e., within normal limits, not within normal limits), is calculated based on high-contrast and low-contrast visual acuity performance. The parameters (i.e., normal, abnormal limits) are based on conservative age norms. Scores show a linear increase for ages older than 50. It is a particularly sensitive measure for reduced visual function that results from certain visual impairments (e.g., optic neuritis, glaucoma, or maculopathy), some of which are age related. In older populations, the test has also demonstrated a strong correspondence with driving performance. Also, test repeatability has proven as good as the standard Snellen Acuity Test (Haegerstrom-Portnoy, Brabyn,

Schneck, & Jampolsky, 1997; Haegerstrom-Portnoy, Schneck, Lott, & Brabyn, 2000; Schneck & Haegerstrom-Portnoy, 2003). From a list of 30 separate medical conditions, participants reported whether they had ever received a diagnosis. Visionrelated diseases, cataracts, glaucoma, diabetic retinopathy, and macular degeneration were selected for this analysis. Additionally, participants indicated the presence of symptoms or problems within a 30-day period. Vision-related symptoms included watery eyes, dry eyes, and runny or itchy eyes. Visionrelated problems included focusing, recognizing at distance, seeing up or down stair steps, seeing through glare from the sun or lights, reading street signs at night, experiencing constricted peripheral vision, and judging distances.

Analysis For each of the 16 eyesight-related conditions (diseases, symptoms, problems, and objective measures), the impact on reported driving limitations due to problems with eyesight was determined by calculating a risk ratio of (a) the percent reporting a limitation when the condition was present to (b) the percent reporting a limitation when the condition was absent. The significance level of this association was calculated using a chi-square statistic. Prevalence of the condition was then combined with the risk ratio to generate an attributable risk for that condition, that is, the impact in the population. The population attributable risk (PAR) is the proportion of the outcome (in this case, driving limitations due to vision) that can be attributable to the exposure (in this case, specific vision-related disease, condition, or symptom). This can be calculated as a percentage (PAR%) as follows: PAR% ¼ (Ppop Punexp)/Ppop 3 100. Ppop is the percentage of those in the total population reporting limitations in driving because of vision, and Punexp is the percentage of those in the ‘‘unexposed’’ group (i.e., those without the specific visionrelated disease, condition, or symptom) who report limitations in driving because of vision. As an example, the overall percentage of those reporting limitations in driving due to vision (Ppop) is 25.4. The percentage of those reporting limitations in driving due to vision that do not report cataracts (Punexp) is 19.6. The formula above yields a PAR% of 22.8 (Last, 2001).

RESULTS Nearly 47% (46.8%, 861/1,840) of the current drivers report that they currently limit or avoid driving for one or more reasons. Problems with vision were the leading self-reported reason for driving limitation or avoidance, especially for women (Table 1). The percent of participants reporting this reason also increased with age for both men and women. Approximately 40% of the women age 75 and older cited vision problems compared with about 29% of the men in the same age group. The significance of vision problems is also demonstrated by examining the percent of medical reasons with involvement of vision. For women age 75 and older, problems with vision constituted nearly 84% of all medical reasons cited for limitations in driving. For men, this figure was nearly 75%. Table 2 gives (a) the prevalence of each of the 16 visionrelated conditions, (b) the percent reporting vision-related limitations in driving for those with and without the condition, (c) the ratio of these percents, and (d) the attributable risk calculated from the prevalence and the ratio. The vision-related


Based on the 1990 U.S. Census of residents in Sonoma, California, ages 55 and older, the original sample of 2,085 subjects overrepresented adults ages 65–73 years (41.3% vs. 38.8% in the general population of Sonoma) and underrepresented adults over age 85 years (7.3% vs. 8.7%). Although differences existed between eligible participants and nonparticipants, the differences do not suggest a consistent pattern with respect to functional disability and chronic illness (Satariano, Smith, Swanson, & Tager, 1998). The study sample is also somewhat more affluent and educated than the population of Sonoma residents age 55 and older. Nevertheless, a comparison of the sample with California residents age 55 and older indicates that the only residents who were underrepresented in the sample were those with household incomes less than $10,000. Similarly, the modal income category of our sample ($25,000–49,000) is the same as the modal income category for the entire state. Finally, there is very little difference among Sonomans or Californians in the percentage of households with annual incomes of $50,000 or more. The current analysis is based on data from the baseline assessment of the SPPARCS cohort. The sample was restricted to subjects who were current drivers who reported whether or not they had personally either limited or avoided driving (N¼1,840). Driving status was established from the participants’ report of their driving behavior and driver license history. Driving status was determined by the participants’ answer to three separate questions: (a) Have you ever had a valid driver’s license? (b) Do you currently have a driver’s license? (c) Have you driven a car in the last 6 months? Participants were considered ‘‘current’’ drivers if they responded ‘‘yes’’ to all three questions. Current drivers were distributed across three age groups: 29.4% were 55–64, 45.0% were 65–74, and 25.7% were 75þ.

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Table 1. Reasons for Limiting or Avoiding Driving by Gender and Age Group, SPPARCS, Wave 1, 1993–1994

Group

Percent With Vision as Limitation to Driving

Percent With One or More Medical Conditions (Including Vision) as Limitation to Driving

Of Medical Limitations, Percent That Are Vision Limitations

20.7 31.7 39.8

26.2 37.4 47.5

79.0 84.8 83.8

9.1 14.6 28.8

13.2 19.0 38.6

68.9 76.8 74.6

Females 55–64 yr (N ¼ 325) 65–74 yr (N ¼ 486) 75þ yr (N ¼ 253) Males 55–64 yr (N ¼ 215) 65–74 yr (N ¼ 341) 75þ yr (N ¼ 220)

Note: SPPARCS ¼ Study of Physical Performance and Age-Related Changes in Sonomans.

DISCUSSION In a previous study reported by this group, older drivers (age 55þ) were much more likely to identify problems with eyesight as a reason for limiting their driving than any other medical condition (Ragland et al., 2004). In this report, we have shown

that specific conditions related to vision (disease processes affecting vision, objective vision tests, reported troubles with vision, and physical symptoms affecting the eye) are each associated, to varying degrees, with reported limitations in driving due to vision. We have calculated the impact of each of the factors in two different ways: (a) as an association of each of the vision-related conditions to reported limitations due to eyesight and (b) as an attributable risk. The ratio of percent reporting limitations among those with and without a specific condition related to vision is relevant to evaluating individuals with that condition; the attributable risk is relevant to planning countermeasures in populations (Rose, 1985). We will discuss the relevance of both measures for each of the types of visionrelated conditions.

Specific Implications of the Findings For the set of disease processes affecting vision, the ratios of the association with vision-related limitations in driving were

Table 2. Visual Difficulties and Driving Limitation, SPPARCS, Wave 1, 1993–1994 Visual Difficulty Limitation Cataracts Glaucoma Macular degeneration

Visual Difficulty and Vision Limitation

Prevalence

Yes (Limit)

No (Limit)

Ratio (Yes/No)a

Attributable Riskb

27.8 7.1 5.2

40.3 45.5 57.3

19.6 23.4 23.3

2.1 1.9 2.5

22.7 6.3 7.1

57.9 52.0

31.2 24.8

15.9 20.6

2.0 1.2

35.8 9.6

4.8 18.3 10.7 8.0 27.7 16.6 3.4 8.4

79.3 44.9 56.7 65.0 44.0 49.0 62.8 55.2

23.1 20.6 21.4 22.1 17.6 19.8 23.6 22.1

3.4 2.2 2.6 2.9 2.5 2.5 2.7 2.5

10.5 17.8 15.0 13.4 29.4 19.7 5.3 11.2

28.0 15.4 31.5

31.3 29.9 28.7

22.2 23.8 22.9

1.4 1.3 1.3

10.3 3.8 7.4

Objective vision tests Glasses/contacts required for driving SKILL Test Reported troubles with vision Avoid physical activity due to vision Past month, trouble focusing Past month, trouble recognizing at distance Past month, trouble seeing steps up/down stairs Past month, trouble with glare from sun/lights Past month, trouble reading street signs at night Past month, trouble with peripheral vision Past month, trouble judging distance Physical symptoms affecting eyes Past month, watery eyes Past month, dry eyes Runny/itchy eyes

Notes: N ¼ 1,840. SPPARCS ¼ Study of Physical Performance and Age-Related Changes in Sonomans; SKILL ¼ Smith–Kettlewell Institute Low Luminance. All ratios are statistically significant. For ‘‘past month, dry eyes’’ and ‘‘runny/itchy eyes,’’ p , 0.05. For all other comparisons, p , 0.001. b Population attributable risk (PAR) % ¼ (Ppop Punexp)/Ppop 3 100. a


conditions vary widely in prevalence, from a low of 3.4% (trouble with peripheral vision) to a high of 57.9% (glasses/ contacts required for driving). For each of the 16 vision-related conditions, the risk ratios are all positive and statistically significant. The ratios range from a low of 1.2 (SKILL Test for visual acuity) to a high of 3.4 (avoid physical activity due to vision). The attributable risk for each of the vision-related conditions is a function of the prevalence of the condition as well as the ratio. Glasses/contacts required for driving has the highest attributable risk (35.8%), having a moderately high ratio of association (2.0) but a very high prevalence (57.9%).

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General Relevance of Vision to Driving In general, findings support previous reports that difficulties with vision are highly associated with increased age and modified or avoidant driving behavior in older adults. However, unlike other studies, this study examined specific types of symptoms and difficulties with vision in association with vision-related driving limitations.

The significance of vision to driving behavior is not surprising as it has been estimated that 90% of driver information is acquired through the visual system (Bailey & Sheedy, 1988). Early vision (here defined to include the ocular media and the retinal transduction and processing) plays a significant role in driving-related tasks as it interacts with higher cognitive functions in crucial skills such as spatial judgment, timely initiation of motor responses, and attention. Older adults are at risk for a variety of decreased functioning within the eye. With age, the eye changes in several ways, leading to several effects. The lens loses elasticity, decreasing the ability to focus, and it yellows, affecting light sensitivity and acuity. Older adults are also more prone to difficulty with ‘‘light scatter’’ within the eye due to either cataracts, corneal opacity, or vitreous defects, which cause problems with glare (Babizhayev, 2003). The pupil of the eye becomes smaller with advanced age, losing ability to allow light in with a consequent reduction of both visual acuity and sensitivity. Also, many retinal disorders that affect acuity and peripheral vision are associated with increased age (Bailey & Sheedy, 1988). Although there are a number of independent dimensions of visual capacity, problems with glare and night vision are the two symptoms most likely to be associated with an older person’s decision to reduce or avoid driving (Theeuwes, Alferdinck, & Perel, 2002). It is possible to enumerate a list of age-related visual conditions, defects, and diseases associated with either glare or night vision deficiencies (Babizhayev, 2003). Some of these are relatively rare, whereas others are more frequently encountered. To confirm these results, future studies are needed to interview older drivers and former drivers about the sequence of events that led to a decision to reduce or avoid driving and, in particular, the extent to which problems with glare and night vision contributed to that decision (Dellinger et al., 2001; Theeuwes et al., 2002; West et al., 2003). It will be important to assess the independent and joint effects of a variety of factors that may operate in conjunction with vision, especially types and levels of cognitive function, to affect driving decision making and performance. It may be that levels of self-efficacy or confidence in the ability to drive represent a possible pathway between visual capacity, health status, and driving behavior. There is a growing body of research that suggests that selfefficacy is strongly associated with daily functioning in a variety of areas, including driving (Dobbs, 2003; Seeman, Unger, McAvay, & Mendes de Leon, 1999). Although self-efficacy was not assessed in the current study, future research in this area will contribute to a better understanding of the effects of vision problems on self-efficacy associated with driving in this population. If these results are confirmed in such studies, clinical and public health strategies to prevent or reduce the effects of these problems should be considered. There is a positive societal benefit that results from retaining the mobility of individuals of advanced age, provided that this can be done without compromising their safety or the safety of others. Strategies range from those taken at a societal level (e.g., headlight regulations that lessen glare to the oncoming driver, signage character size and illumination at night, and licensure requirements) to those undertaken by individuals (e.g., decision to undergo cataract surgery, decision to forgo refractive surgery, scrupulous maintenance of vehicle windscreen clarity). Beyond


fairly high (1.9 and above). For individuals with these diseases (cataracts, glaucoma, and macular degeneration), the impact on driving is an important consideration, and ways to mitigate this impact should be developed. For example, there is evidence that cataract surgery reduces crash risk associated with cataracts (Owsley et al., 1999). Although the degree of association is similar for the three diseases, cataracts had the highest impact in terms of attributable risk, as the prevalence of that condition is substantially higher than that for the other two diseases. Because so few participants reported having diabetic retinopathy, it was not included in this analysis. Standardized measures of visual capacity recorded in this study show a different pattern. The ratio of association for the SKILL Test is very low (1.2), showing that this measure of visual acuity under light and dark conditions is not very relevant for vision-related limitations of driving. Other standardized measures of vision, such as the Useful Field of Vision, although not assessed in the current study, may be more appropriate for assessing visual capacity for driving (Owsley et al., 2001). Glasses/contacts required for driving had a relatively high ratio of association (2.0). One possibility is that needing glasses/contacts is a marker for other vision-related problems. Another possibility is that some proportion of glasses/contacts are not well prescribed or well suited for the complex and varied visual tasks associated with driving. It may be that glasses/contacts could be designed to reduce vision-related driving limitations. This might be an effective strategy from not only an individual perspective but also a population viewpoint, as the prevalence and subsequently the attributable risk are high (57.9% and 35.8%, respectively). The eight reported troubles with vision all had a high ratio of association with vision-related limitations in driving (ranging from 2.2 to 3.4). Most of these have specific implications with respect to driving. For example, problems with focusing, depth, glare, peripheral vision, and nighttime vision might be correctable. These same problems might be addressed by highway design through modification of signs, signals, highway markings, and lighting. The Federal Highway Administration has published a Highway Design Handbook (Staplin, Lococo, Byington, & Harkey, 2001) that has recommendations addressing some of these issues. Work is needed to extend and implement these recommendations. A consideration of prevalence and subsequent attributable risk of these problems might be used to judge the relative benefits of addressing particular troubles with vision. For example, trouble with glare from sun/lights and trouble reading street signs at night have the highest attributable risk and could be addressed by changes in signs and lighting. Physical symptoms affecting the eyes (i.e., watery eyes, dry eyes, and runny/itchy eyes) showed very low ratios of association with vision-related limitations in driving; and even though the prevalence of these symptoms was relatively high, the attributable risks were also fairly low.

VISION AND LIMITATIONS OF DRIVING

such strategies, there are varieties of promising infrastructure improvements under study that can become sensory extensions for drivers. These include in-vehicle machine vision capabilities, smart signals and signs, and infrastructure communications to vehicles and their drivers that complement the sensory capabilities of drivers. Finally, as noted previously, it will be important to determine whether changes in self-efficacy represent a possible pathway between these interventions and the timing, location, and quality of driving performance in older populations. ACKNOWLEDGMENTS

REFERENCES Babizhayev, M. A. (2003). Glare disability and driving safety. Ophthalmic Research, 35, 19–25. Bailey, I. L., & Sheedy, J. E. (1988). Vision screening and driving licensure. In Transportation in an aging society (Special Report 218, pp. 294–324). Washington, DC: Transportation Research Board, National Research Council. Ball, K., Owsley, C., Stalvey, B., Roenker, D.L., Sloane, M.E., & Graves, M. (1998). Driving avoidance and functional impairment in older drivers. Accident Analysis and Prevention, 30, 313–322. Campbell, K., Bush, T., & Hale, W. (1993). Medical conditions associated with driving cessation in community-dwelling, ambulatory elders. Journal of Gerontology: Social Sciences, 48B, S230–S234. Dellinger, A. M., Sehgal, M., Sleet, D. A., & Barrett-Connor, E. (2001). Driving cessation: What older former drivers tell us. Journal of the American Geriatrics Society, 49, 431–435. Dobbs, B. M. (2003). Understanding older drivers: The importance of selfperception of competency. Presented at the MIT AgeLab/The Hartford Financial Services Group Symposium: The Driving Decision: Health, Safety, and the Older Driver, Cambridge, MA, May 13. Fonda, S. J., Wallace, R. B., & Herzog, A. R. (2001). Changes in driving patterns and worsening depressive symptoms among older adults. Journal of Gerontology: Social Sciences, 56B, S343–S351. Gallo, J. J., Rebok, G. W., & Lesikar, S. E. (1999). The driving habits of adults aged 60 years and older. Journal of the American Geriatrics Society, 47, 335–341. Gilhotra, J. S., Mitchell, P., Ivers, R., & Cumming, R. G. (2001). Impaired vision and other factors associated with driving cessation in the elderly: The Blue Mountains Eye Study. Clinical and Experimental Ophthalmology, 29, 104–107. Haegerstrom-Portnoy, G., Brabyn, J., Schneck, M. E., & Jampolsky, A. (1997). The SKILL Card. An acuity test of reduced luminance and contrast. Investigative Ophthalmology and Visual Science, 38, 207–218. Haegerstrom-Portnoy, G., Schneck, M. E., Lott, L. A., & Brabyn, J. A. (2000). The relation between visual acuity and other spatial vision measures. Optometry and Vision Science, 77, 653–662. Last, J. M. (2001). Dictionary of epidemiology. New York: Oxford University Press. Lyman, J. M., McGwin, G., Jr., & Sims, R. V. (2001). Factors related to driving difficulty and habits in older drivers. Accident Analysis and Prevention, 33, 413–421.

Marottoli, R. A., Mendes de Leon, C. F., Glass, T. A., Williams, C. S., Cooney, L. M., Jr., Berkman, L. F., et al. (1997). Driving cessation and increased depressive symptoms: Prospective evidence from the New Haven EPESE. Journal of the American Geriatrics Society, 45, 202– 206. Marottoli, R. A., & Richardson, E. D. (1998). Confidence in, and self-rating of, driving ability among older drivers. Accident Analysis and Prevention, 30, 331–336. McGwin, G., Chapman, V., & Owsley, C. (2000). Visual risk factors for driving difficulty among older drivers. Accident Analysis and Prevention, 32, 735–744. McGwin, G., Sims, R. V., Pulley, L., & Roseman, J. M. (2000). Relations among chronic medical conditions, medications, and automobile crashes in the elderly: A population-based case-control study. American Journal of Epidemiology, 152, 424–431. Owsley, C., Stalvey, B., Wells, J., & Sloane, M. E. (1999). Older drivers and cataract: Driving habits and crash risk. Journal of Gerontology: Medical Sciences, 54, M203–M211. Owsley, C., Stalvey, B. T., Wells, J., Sloane, M. E., & McGwin, G., Jr. (2001). Visual risk factors for crash involvement in older drivers with cataracts. Archives of Ophthalmology, 119, 881–887. Ragland, D. R., Satariano, W. A., & MacLeod, K. E. (2004). Reasons given by older people for limitation or avoidance of driving. The Gerontologist, 44, 237–244. Rose, G. (1985). Sick individuals and sick populations. International Journal of Epidemiology, 14, 32–38. Satariano, W. A., Smith, J., Swanson, A., & Tager, I. B. (1998). A censusbased design for the recruitment of a community sample of older adults: Efficacy and costs. Annals of Epidemiology, 8, 278–282. Schneck, M. E., & Haegerstrom-Portnoy, G. (2003). Practical assessment of vision in the elderly. Ophthalmology Clinics of North America, 16, 269–287. Seeman, T. E., Unger, J. B., McAvay, G., & Mendes de Leon, C. F. (1999). Self-efficacy beliefs and perceived declines in functional ability: MacArthur studies of successful aging. Journal of Gerontology: Psychological Sciences, 54B, P214–P222. Sims, R. V., Owsley, C., Allman, R. M., Ball, K., & Smoot, T. M. (1998). A preliminary assessment of the medical and functional factors associated with vehicle crashes by older adults. Journal of the American Geriatrics Society, 46, 556–561. Staplin, L., Lococo, K., Byington, S., & Harkey, D. (2001). Highway design handbook for older drivers and pedestrians. McLean, VA: Federal Highway Administration. Stewart, R. B., Moore, M. T., Marks, R. G., May, F. E., & Hale, W. E. (1993). Driving cessation and accidents in the elderly: An analysis of symptoms, diseases, cognitive dysfunction and medications. Washington, D.C.: AAA Foundation for Traffic Safety. Stutts, J. C. (1998). Do older drivers with visual and cognitive impairments drive less? Journal of the American Geriatrics Society, 46, 854–861. Theeuwes, J., Alferdinck, J. W. A. M., & Perel, M. (2002). Relation between glare and driving performance. Human Factors and Ergonomics Society, 44, 95–107. West, C. G., Gildengorin, G., Haegerstrom-Portnoy, G., Lott, L. A., Schneck, M. E., & Brabyn, J. A. (2003). Vision and driving selfrestriction in older adults. Journal of the American Geriatrics Society, 51, 1348–1355. West, S. K., Munoz, B., Rubin, G. S., Schein, O. D., Bandeen-Roche, K., Zeger, S., et al. (1997). Function and visual impairment in a populationbased study of older adults. The SEE Project. Salisbury eye evaluation. Investigative Ophthalmology and Visual Science, 38, 72–82. Received February 26, 2003 Accepted April 28, 2004 Decision Editor: Charles F. Longino, Jr., PhD


This research was supported by Contract Agreement Number DTNH2200-H-05249 from the National Highway Traffic Safety Administration and Grant R01 AG09389 from the National Institute on Aging. Address correspondence to Dr. William A. Satariano, Division of Epidemiology, School of Public Health, 140 Warren Hall, University of California at Berkeley, Berkeley, CA 94720-7360. E-mail: bills@uclink. berkeley.edu

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APPENDIX A Percent of Participants Giving Specific Reasons for Limitation of Driving by Gender and Age, SPPARCS, Wave 1, 1993–1994 Female Limitation

Male

55–64 yr (n ¼ 328)

65–74 yr (n ¼ 492)

75þ yr ( n ¼ 274)

55–64 yr (n ¼ 219)

65–74 yr (n ¼ 343)

75þ yr (n ¼ 233)

20.7 0.0 1.2 0.3 0.0 0.9 4.0 1.8 1.2 0.3 0.9 1.2 1.2 1.2

31.7 0.0 1.0 0.6 0.2 0.6 4.1 1.6 1.4 0.4 1.0 3.5 0.4 1.0

39.8 0.7 1.1 1.1 0.0 1.5 4.1 2.2 1.5 0.4 2.6 6.7 2.2 4.8

9.1 0.0 0.5 0.0 0.5 0.0 2.7 0.0 0.5 0.5 0.9 1.8 0.9 1.4

14.6 0.6 0.6 0.0 0.0 0.0 2.0 0.6 0.6 0.3 1.2 2.3 1.2 0.6

28.8 0.0 0.4 0.9 0.4 0.0 3.5 2.2 1.7 0.9 0.9 5.6 2.6 5.6

0.3 6.1 9.8 3.4 3.7 11.9 6.1

0.6 9.0 15.0 4.1 4.5 21.8 7.4

3.0 17.8 17.0 4.8 8.9 27.4 9.3

0.0 1.4 3.2 0.0 1.4 8.7 4.1

0.3 6.7 5.3 0.9 1.5 11.4 5.9

0.9 16.9 4.3 2.6 2.6 16.9 5.6

Medical limitations

Nonmedical limitations No access to a reliable car Concerned about being in accident Concerned about crime Concerned about getting lost No one to drive with No reason to drive Too busy to drive

Note: SPPARCS ¼ Study of Physical Performance and Age-Related Changes in Sonomans.


Problems with eyesight Problems with hearing Problems with arthritis Problems with keeping balance Problems with breathing Problems with dizziness Problems with fatigue or tired Feeling confused Difficulty concentrating Chest pain, pressure, etc. Disability due to past injury Other health problems Physician’s recommendation Family recommendation