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As ophthalmologists, we are often asked to comment on whether particular patients of ours have adequate vision to operate a motor vehicle safely. Although our determinations are guided by objective criteria, involving legally imposed threshold levels of visual acuity and visual fields, these criteria can vary from one locality to the next and are substantiated by little research.
The importance of early detection and treatment of OAG, before the disease becomes severe enough to affect the patient's ability to perform activities such as driving is reinforced
To assess whether patients with glaucoma-related vision loss can see well enough to drive safely, Tanabe et al. (1662) administered a questionnaire to 265 consecutive patients in a clinic in Japan, including patients with open-angle glaucoma (OAG) and persons without ocular disease, who served as controls. Specifically, the researchers evaluated whether patients' level of severity of open-angle glaucoma (OAG) was associated with their likelihood of being involved as a driver in a motor vehicle accident, relative to controls'. They found little difference in the odds of self-reported involvement in a driving accident between patients with mild or moderate OAG and control participants. However, the odds were sixfold higher among patients with severe OAG, defined as those with a mean deviation worse than -10 decibels. If these study findings can be replicated in a sample that is larger (only 20 patients had severe OAG) and more ethnically diverse, they justify authorities' reevaluation of whether existing requirements in their locality for driver's license renewal are stringent enough. Yet, in so doing, authorities must consider not only important concerns about public safety but also the individual quality-of-life interests of the patients with OAG whose driving privileges are potentially at stake, given that possessing a driver's license is so closely tied to adults' ability to maintain their independence. On the basis of the study findings, the authors call for a large-scale nationwide study to better understand the type and degree of visual field loss that predisposes patients with OAG to motor vehicle accidents. This study also reinforces the importance of early detection and treatment of OAG, before the disease becomes severe enough to affect the patient's ability to perform activities such as driving.