Evaluating clinical change and visual function concerns in drivers and nondrivers with glaucoma

Abstract

Purpose: To compare drivers and nondrivers, and to describe the specific concerns of drivers, among individuals with glaucoma.

Methods: Six hundred seven patients with newly diagnosed glaucoma treated at 14 clinical centers of the Collaborative Initial Glaucoma Treatment Study were randomly assigned to initial medicine or surgery and were followed up every 6 months. Driving status (drivers versus nondrivers) and patient-reported visual function were determined by the Visual Activities Questionnaire and the National Eye Institute Visual Function Questionnaire. Clinical evaluation included visual field mean deviation (MD) and visual acuity. Statistical comparisons were made using t, chi(2), and exact tests and regression and Rasch analyses.

Results: Drivers were more likely than nondrivers to be male, white, married, employed, and more educated and to have higher incomes and fewer comorbidities. More than 50% of drivers reported at least "some" difficulty performing tasks involving glare, whereas 22% reported at least "some" difficulty with tasks requiring peripheral vision. At 54 months, drivers with moderate/severe bilateral visual field loss (VFL) reported greater difficulty with night driving and tasks involving visual search and visual processing speed than drivers with less bilateral VFL (all P<0.05). Although those who remained drivers over follow-up had better MD in both eyes than those who became nondrivers because of eyesight, a number of drivers had marked VFL.

Conclusions: Inquiring about specific difficulties with tasks related to glare, visual processing speed, visual search, and peripheral vision in driving, especially among patients with substantial bilateral visual field damage, will enable physicians to more effectively counsel patients regarding driving.

Figure 1

Visual Activities Questionnaire Driving Items by percent reporting specific visual function concerns among drivers at 6 months

Figure 2

Visual Activities Questionnaire, the proportion endorsed for each question, by the number of endorsed driving items. We dichotomized each of the five responses as “sometimes” or more often (i.e., endorsed as a concern) versus “rarely” or “never”.

Figure 2

Visual Activities Questionnaire, the proportion endorsed for each question, by the number of endorsed driving items. We dichotomized each of the five responses as “sometimes” or more often (i.e., endorsed as a concern) versus “rarely” or “never”.

Figure 3

Visual Activities Questionnaire and National Eye Institute-Visual Function Questionnaire Driving Items by level of bilateral visual field loss at 54 months. Findings reported for Glare (VAQ) are the average of drivers’ responses to the two VAQ items on glare

Figure 4

Mean Deviation in worse eye over time by driving status based on the Visual Activities Questionnaire (0–4.5 years) and National Eye Institute-Visual Function Questionnaire (4.5 – 6.5 years)

Figure 5

Boxplot showing the distribution of mean deviation values at 54 months by National Eye Institute- Visual Function Questionnaire driving status. Boxes extend from the 25th to 75th percentile. The crossbar is at the median, and the “+” sign indicates the mean. Whiskers extend to the nearest point within 1.5 times the interquartile range. Points beyond whiskers are indicated as outliers