To investigate the relationship between self-perceived driving difficulty, driving avoidance, and negative emotion about driving with glaucoma severity and on-road driving performance.
Glaucoma patients (n = 111), aged 55 to 90 years, with mild, moderate, and advanced glaucoma in the better-eye based on the Glaucoma Staging System, and age-matched controls (n = 47) were recruited from a large tertiary academic center. Self-reported questionnaires were administered by a trained occupational therapist followed by a standardized on-road driving evaluation (pass vs “at-risk” score) with a masked and certified driving rehabilitation specialist.
Compared to controls, glaucoma participants reported greater driving difficulty with as early as mild glaucoma ( P = .0391) and negative emotion about driving starting with moderate glaucoma ( P = .0042). Glaucoma participants reporting at least 1 driving difficulty and negative emotion had a 3.3-fold (adjusted odds ratio [OR] = 3.3; 95% CI = 1.24-8.52; P = .0163) and 4.2-fold (adjusted OR = 4.2; 95% CI = 1.5-12.2; P = .0078) greater odds, respectively, of an at-risk score on the on-road test. Self-reported driving difficulty in “difficult” conditions ( P = .0019), rain ( P = .0096), interstates ( P = .0378), and high traffic ( P = .0076), driving avoidance on sunny ( P = .0065) and cloudy ( P = .0043) days, and driving fewer days per week ( P = .0329) were also associated with at-risk driving.
Screening tools that assess self-perceived driving difficulty and driving avoidance in specific conditions, negative emotion about driving, and driving exposure may help identify unsafe drivers with glaucoma. Some of these drivers, particularly those with modest glaucoma, may benefit from a driving evaluation and early referral to resources that could enable them to continue driving safely and confidently.
T he number of older drivers with glaucoma is rapidly rising with the increasing older driver population. This is a major cause for concern, given that drivers with glaucoma are at a higher risk for being at fault and/or injured in a motor vehicle collision (MVC) than are drivers without glaucoma. In addition, older drivers with glaucoma have a higher self-reported driving difficulty, driving avoidance, and driving cessation, which may lead to negative sequelae including social isolation, depression, and decreased independence and quality of life. Identifying drivers with glaucoma who are at greatest risk for a MVC, as well as those who are potentially safe drivers but perceive difficulty driving, experience negative emotions, and/or unnecessarily restrict their driving, is critical to help improve their safety and quality of life.
Self-reported driving difficulty and driving self-restrictions are greater in drivers with glaucoma than in drivers without glaucoma and increase with worsening glaucoma severity as well as bilateral disease. Relatively little is known, however, about whether these self-perceptions accurately reflect real-life driving in older drivers with glaucoma or the stage of glaucoma when these perceptions increase compared to those in drivers without glaucoma. , In addition, the emotional impact that these difficulties and limitations may have on a driver’s mental well-being as well as their actual driving abilities is highly important, yet often not assessed in driving studies of individuals with glaucoma.
Understanding the relationships between a driver’s insight regarding their driving abilities, driving behaviors, emotion, and real-life driving safety is essential to improve driving safety in older adults with glaucoma. This information can be used to develop screening tools to help identify unsafe drivers with glaucoma who continue to drive unrestricted and potentially pose a risk to themselves and society. Screening tools may also help identify potentially safe drivers with glaucoma who restrict their driving and experience the negative cascade of consequences associated with driving avoidance and cessation. Furthermore, identifying specific driving conditions that are associated with perceived driving difficulty, driving avoidance, or negative emotion about driving may help guide interventions (eg, self-regulatory behaviors, optical aids, scanning strategies, counseling) to promote and prolong safe and confident driving in potentially safe drivers with glaucoma.
The purpose of this report is to investigate whether self-perceptions of driving difficulty, driving avoidance, and negative emotion about driving accurately reflect driving performance on an on-road test in drivers with glaucoma of varying disease severity. This report also aims to determine the stage of glaucoma at which these self-perceptions and negative emotions increase compared to those in drivers without glaucoma.
This was a single-center, cross-sectional study conducted by a multidisciplinary team of experts in accordance with the Declaration of Helsinki and approved by the Human Research Protection office at Washington University School of Medicine in Saint Louis, Missouri. Written informed consent was obtained from all eligible participants prior to study participation.
A total of 158 participants aged 55 to 90 years, with a clinical diagnosis of glaucoma (n = 111) and age-range−matched controls (n = 47) with a diagnosis of ocular hypertension, glaucoma suspect, or no ocular disease participated in this study. Glaucoma participants and controls were recruited during their regularly scheduled eye clinic visits at Washington University School of Medicine, St. Louis, Missouri. All participants completed their visits between April 2017 and October 2019.
Study eligibility for participants was determined by chart review of consecutive patients from selected glaucoma and comprehensive eye clinics. Individuals were excluded if they had the following: (1) advanced cardiopulmonary disease requiring oxygen or class IV congestive heart failure; (2) severe orthopedic, musculoskeletal, or neuromuscular impairments requiring adaptive equipment to ambulate; (3) a clinical diagnosis of moderate or severe dementia; (4) a hearing or language impairment impeding effective communication; (5) a history of unstable disease such as diabetes with recurrent hypoglycemic events or uncontrolled seizures; (6) a history of psychiatric illness or substance abuse requiring hospitalizations or rehabilitation; (7) use of potentially sedating medications (eg narcotics or anxiolytics); (8) neovascular, uveitic, or acute angle closure glaucoma; (9) non-glaucomatous vision impairments (eg, macular degeneration, visually significant cataracts); (10) low vision aids for driving; (11) ocular surgery within the previous 3 months; or (12) completion of a driving evaluation within the past 1 year.
All study participants were required to be currently driving with a valid driver’s license, to have a visual acuity of 20/70 or better in at least 1 eye in compliance with Missouri and Illinois vision requirements for licensure for daytime driving, to speak English, and to have at least 10 years of driving experience. Participants were screened for significant cognitive impairment and required to score <9 on a brief cognitive screen, the Short Blessed Test.
Patients with glaucoma were identified based on glaucomatous optic nerve cupping and reproducible visual field defects consistent with glaucoma on the Humphrey Visual Field (VF) Analyzer II (Carl Zeiss Meditec) equipped with the Swedish Interactive Threshold Algorithm (SITA) obtained within 6 months of the study. Visual field tests were performed for glaucoma participants who did not have a visual field test within 6 months of the study and for all controls. For study eligibility, visual field tests were required to have less than 20% false-positive results and less than 30% false-negative results and fixation losses. For glaucoma participants, each eye was classified into a glaucoma stage (0-5) based on visual field testing using the Glaucoma Staging System and further classified as mild (stages 0 and 1), moderate (stages 2 and 3), or advanced (stages 4 and 5) glaucoma based on the stage in the better eye (ie, lower stage). Visual fields for controls were examined to ensure that there were no specific defects associated with glaucoma or other ocular pathology.
All consenting participants completed a comprehensive clinical assessment of vision, cognition, and motor function and self-reported questionnaires at the Washington University Driving and Research Center. Of the clinical assessments, 96% were administered by the same trained occupational therapist who is certified in low vision rehabilitation (SCLV), and the other 4% were administered by another trained occupational therapist. The measures listed below were used in this report.
Vision assessments were obtained with the participant’s habitual correction. Binocular distance visual acuity was measured using a back-lit ETDRS chart (Vector Vision CSV 1000) at 3.2 meters testing distance. Binocular near visual acuity was measured using the Lighthouse Near Visual Acuity card (Precision Vision, Catalog No. C175) at the participant’s preferred reading distance. Distance and near visual acuity were scored as the number of letters correctly identified and converted to logMAR. Binocular contrast sensitivity (CS) was measured using the MARS Letter Contrast Sensitivity chart (Mars Perceptrix, Catalog No. MLCST) at 0.5 meter. , Binocular CS with glare testing was measured using bilateral Brightness Acuity Test (BAT) (Mentor) on low and medium settings with a MARS Letter CS chart version different from that used for CS testing. Log contrast sensitivity scores from the CS and CS with glare tests on medium BAT setting were analyzed for this report. Monocular visual field testing was obtained as previously described, and binocular visual field testing was obtained with the Esterman test using the Esterman Disability Score (range 0-100).
The Driving Questionnaire (eAppendix) is a 61-item self-reported driving assessment including the 25-list-item National Eye Institute Visual Function Questionnaire (NEI-VFQ 25) Driving Subscale and Driving Habits Questionnaire. For this report, we analyzed 6 questions regarding driving difficulty in conditions that are challenging to modify. Three questions were obtained from the NEI-VFQ 25 Driving Subscale (questions 15c, 16, and 16a) to assess difficulty driving during the daytime in familiar places, at night, and in difficult conditions (bad weather, rush hour, freeway, city traffic). Three additional questions were obtained from the Driving Habits Questionnaire (questions 17b, 21b, and 22b) to assess difficulty driving in the rain, on interstate highways, and on high-traffic roads. Level of driving difficulty of each condition was measured on a 4-point Likert scale ranging from no difficulty at all, a little difficulty, moderate difficulty, and extreme difficulty. For the purposes of this report, participants who experienced “moderate” or “extreme” difficulty were categorized as having driving difficulty. Of the 158 participants, 146 (92.4%) completed 100% of questions on driving difficulty.
The Driving Strategy Questionnaire (unpublished, eAppendix) is a 2-part self-reported questionnaire developed by our research team to evaluate strategies that participants use while driving. In the first part, participants were asked to list any strategies they may use to drive safely. The second part consists of 16 conditions and areas that participants may avoid while driving and 10 strategies that participants may use to drive more safely. For this report, driving avoidance was evaluated by analyzing the level of avoidance of 6 driving conditions that are difficult to modify. These 6 driving conditions included night, sunny days, cloudy days, high traffic, interstate, and unfamiliar areas. Driving conditions at night, in high traffic, and on interstates were derived from the Driving Habits Questionnaire and the NEI-VFQ 25, which inquire about driving difficulty in these specific driving conditions. Driving conditions on sunny days, on cloudy days, and in unfamiliar areas were based on an extensive literature review of difficult driving conditions for glaucoma drivers and the clinical experience of the research team, which included a driving vision rehabilitation specialist, a low vision rehabilitation specialist, and a glaucoma specialist. Level of driving avoidance was measured on a 5-point Likert scale (never, rarely, sometimes, frequently, always). Avoidance levels of “sometimes,” “frequently,” or “always” were categorized as the participant having a driving avoidance. All 158 of the participants (100%) completed 100% of questions on driving avoidance.
In the Driving Questionnaire, participants were asked “How much does being limited by your driving bother you?” Level of “bother” (ie, negative emotion) was measured on a 5-point Likert scale (not at all, a little, somewhat, a great deal, an extreme amount). Participants who responded “somewhat,” “a great deal,” or “an extreme amount” were categorized as having negative emotion. Of the 158 participants, 155 (98.1%) completed this question.
Driving exposure was evaluated by a question obtained from the Driving Habits Questionnaire. Participants were asked “In an average week, how many days per week do you normally drive?” Responses ranging from 0 to 7 were included in the analysis. Of the 158 participants, 154 (97.4%) completed this question.
On-road driving evaluation
An on-road driving evaluation was conducted immediately following the clinical assessment. The modified Washington University Road Test (mWURT) is a valid, reliable, 13-mile on-road driving test in a predetermined area of St. Louis, Missouri, that has been used in prior studies. All on-road tests were conducted by the same driving evaluator, who is a certified occupational therapist and driving rehabilitation specialist (CDRS), and different from the clinician who administered the clinical assessments. The driving evaluator was masked to the participant’s diagnosis, vision status and performance on the clinical assessments. The on-road tests were scheduled during weekdays between 9 AM and 4 PM and were not performed in inclement weather such as severe rain, snow, on icy road conditions, or during rush hour traffic. The driving evaluator was seated in the passenger seat and scored driving performance quantitatively and qualitatively using the Record of Driving Errors (RODE). The driving evaluator also provided directional instructions, safety monitoring, and necessary interventions using dual brake, steering wheel guidance, and/or verbal assistance as deemed necessary for safety during the test. Qualitative scores were used for this report and were grouped into an overall driving score of “pass,” “marginal pass,” and “fail.” A pass score indicated no safety concern, a marginal score indicated low to moderate safety concern (eg, rolling through a stop sign), and a fail score indicated major safety concern (eg, failing to yield to a pedestrian). Marginal pass and fail scores were classified as “at-risk” scores for driving safety. All 158 participants (100%) completed the on-road test.
Descriptive statistics were used to analyze demographic data, clinical assessments, and driving performance. Differences in baseline demographics by glaucoma status were determined using the Kruskal−Wallis test for continuous outcomes and χ 2 test for categorical outcomes. Univariate, unadjusted, and adjusted (age, sex, and race) logistic regression models were used to estimate the association between predictors (glaucoma status, driving difficulty, driving avoidance, negative emotion, and driving exposure) and driving performance. Driving performance was dichotomized as pass or at-risk. Odds ratios were used to determine the magnitude of the association between predictors and driving performance. All data analyses were performed using SAS version 9.4 (SAS Inc).
Baseline characteristics of 158 participants in this study are included in Table 1 . The glaucoma and control groups had a similar mean age (70.4 ± 7.5 vs 68.7 ± 7.3 years), percentage of female participants (50.5% vs 51.1%), and days driven per week (5.4 ± 2.0 vs 5.9 ± 1.6). There were more participants in the glaucoma group than in the control group who were African American (31.5% vs 23.4%), and more participants in the control group than in the glaucoma group who had diabetes (27.7% vs 19.8%); however, these differences were not statistically significant. The percentage of pseudophakia status in at least 1 eye was significantly greater in the glaucoma group than in the control group (62.2% vs 29.8%). Both the glaucoma and control groups scored similarly on the Short Blessed Test (mean score, 1.4 vs 1.1). The glaucoma group scored worse than did the control group on all vision measures ( P < .05) including monocular visual field mean deviation (better and worse eye), distance and near visual acuity, contrast sensitivity, contrast sensitivity with glare testing, and Esterman binocular visual field disability score.
|Glaucoma (N=111)||Controls (N=47)||P-value|
|Age, mean years (SD)||70.4 (7.5)||68.7 (7.3)||0.2384|
|Sex (female), %||50.5||51.1||0.9438|
|Race (African American), %||31.5||23.4||0.3039|
|At least some college, %||73.0||74.5||0.8458|
|Pseudophakia in at least one eye, %||62.2||29.8||0.0002|
|Short Blessed Test, mean score (SD)||1.4 (2.2)||1.1 (1.9)||0.3981|
|Days driven per week (SD)||5.4 (2.0)||5.9 (1.6)||0.2045|
|Best eye VF mean deviation, mean (SD)||-5.0 (6.3)||0.0 (1.4)||<0.0001|
|Worst eye VF mean deviation, mean (SD)||-9.7 (7.7)||-1.2 (1.8)||<0.0001|
|ETDRS Distance VA LogMAR, mean (SD)||0.63 (0.1)||0.58 (0.1)||0.0210|
|Lighthouse Near VA LogMAR, mean (SD)||0.41 (0.2)||0.33 (0.2)||0.0264|
|MARS log Contrast Sensitivity, mean (SD)||1.6 (0.2)||1.7 (0.1)||<0.0001|
|MARS log Contrast Sensitivity, BAT medium mean (SD)||1.5 (0.2)||1.6 (0.1)||<0.0001|
|Esterman Disability score, mean (SD)||89.8 (14.2)||97.1 (4.0)||0.0018|
Self-reported moderate or extreme driving difficulty with at least 1 of 6 driving conditions occurred in 53 of 110 glaucoma participants (48.2%) compared to 8 of 46 controls (17.4%) ( Figure 1 ). Glaucoma participants had a 4.3-fold greater risk of reporting moderate or extreme driving difficulty compared to controls (adjusted OR = 4.3; 95% CI = 1.80-10.24; P = .0010) ( Table 2 ). Self-reported driving difficulty increased with worsening glaucoma severity, in 22 of 54 participants (40.7%) with mild, 21 of 42 participants (50.0%) with moderate, and 11 of 14 participants (78.6%) with advanced glaucoma ( Figure 2 ). Compared to controls, self-reported moderate or extreme driving difficulty was significantly greater in the mild (adjusted OR = 2.8; 95% CI = 1.05-7.23; P = .0391), moderate (adjusted OR = 5.3; 95% CI = 1.90-14.53; P = .0014), and advanced (adjusted OR = 22.3; 95% CI = 4.59-108.59; P = .0001) glaucoma groups ( Table 2 ).
|Unadjusted OR (95% CI)||P-value||Adjusted a OR (95% CI)||P-value|
|Control (reference group) (n=46)||1.0||1.0|
|Mild Glaucoma Stage (n=54)||3.02 (1.18-7.72)||0.0209||2.76 (1.05-7.23)||0.0391|
|Moderate Glaucoma Stage (n=42)||4.75 (1.79-12.57)||0.0017||5.26 (1.90-14.53)||0.0014|
|Advanced Glaucoma Stage (n=14)||17.42 (3.94-77.04)||0.0002||22.32 (4.59-108.59)||0.0001|
|Total Glaucoma (n=110)||4.42 (1.89-10.33)||0.0006||4.29 (1.80-10.24)||0.0010|
|Control (reference group) (n=47)||1.0||1.0|
|Mild Glaucoma Stage (n=55)||1.99 (0.86-4.61)||0.1095||1.86 (0.78-4.42)||0.1627|
|Moderate Glaucoma Stage (n=42)||2.80 (1.06-7.37)||0.0370||2.53 (0.94-6.82)||0.0664|
|Advanced Glaucoma Stage (n=14)||4.07 (0.82-20.29)||0.0867||2.89 (0.55-15.26)||0.2121|
|Total Glaucoma (n=111)||2.43 (1.16-5.08)||0.0182||2.17 (1.02-4.64)||0.0458|
|Control (reference group) (n=46)||1.0||1.0|
|Mild Glaucoma Stage (n=54)||1.79 (0.42-7.60)||0.1024||1.61 (0.37-6.93)||0.5209|
|Moderate Glaucoma Stage (n=42)||7.00 (1.84-26.61)||0.0304||7.28 (1.87-28.34)||0.0042|
|Advanced Glaucoma Stage (n=14)||10.50 (2.17-50.91)||0.0124||11.75 (2.20-62.71)||0.0039|
|Total Glaucoma (n=110)||4.39 (1.26-15.33)||0.0206||4.08 (1.16-14.40)||0.0289|