Description

In spite of decades of improvement in road and vehicle design, road accidents continue to exact a heavy toll of death and injury. Indeed, this heavy toll has become so much a part of our lives that a daily UK total of about 10 road deaths excites little comment in our media, in contrast to the attention devoted to the much rarer accidents involving other means of transport. Since there is little doubt that drivers use vision to acquire most of their information on the road environment, it is reasonable to ask whether some accidents can be traced back to the defective vision of the drivers involved. If this link proves to be the case, then it is possible that regular, more detailed tests of drivers vision might help to screen out accident-prone drivers, with a consequent reduction in the accident figures.

Several immediate questions arise at this point. Can it be demonstrated that those drivers with visual defects are likely to make driving errors which lead to accidents? If we examine accident statistics, can it be shown that there is a strong correlation between actual accident figures and the type and severity of visual defect? Do our current visual standards for drivers take proper account of the available evidence on the links between defective vision and accident risk?

This issue of CE Optometry contains a group of papers by distinguished experts in the field, which go a considerable way to answering these questions. As Wood makes clear, there is little doubt that visual impairment can affect driving performance, and that the impact of impairment is greater for the older driver, a topic discussed in more detail by Taylor. This link is reflected by an increase in average accident rate per mile for the older driver. On the other hand, studies to date cannot demonstrate that those with specific visual defects will necessarily have accidents in their driving career. Moreover, a low mileage, higher-risk driver may well have less accidents than some high-mileage, low-risk drivers. Factors other than the individuals vision have considerable influence on accidents: for example, accident rates are highest among young drivers where visual standards are high.

The question of standards is discussed, in separate articles, by Jenkins and Jones, who make it clear that, contrary to the widespread belief that the only visual requirement for drivers is that they can pass the number plate test, drivers are responsible for notifying the DVLA of any relevant disability, such as glaucoma, retinitis pigmentosa or diabetic retinopathy and that these disabilities may be grounds for withdrawal of a license.

Two important points arise from these reviews. The first is that although the visual requirements nominally screen out drivers with marked visual defects, in practice they only do this to a limited extent, since defects are self-reported rather than being detected by a regular, formal, testing procedure. The second is that a more rigorous testing of vision would primarily result in a license loss for older drivers.

What actions should our legislators take in the light of available information? Introduction of an enhanced vision testing programme would be expensive and unpopular. As Taylor points out, loss of a driving license in our car-based society results in a great loss in mobility for those involved. In an era when many small communities are losing local employment, shops and other facilities, while public transport is lacking, inability to use a car greatly reduces the potential quality of life.

The thrust of legislation in the area of disability in general is to widen access to facilities and services, rather then to deny it. It is therefore difficult to see politicians putting forward legislation to change substantially the present standards and, indeed, if any change occurs it is likely to be in the direction of relaxing standards in some respects, as discussed by Peli for low vision patients in the North American context. Government could, however, do much more to regularly publicize the visual requirements for a driving license: consideration could, perhaps, be given to ideas such as the provision of testing ranges outside, e.g. post offices, to allow frequent self-testing of at least the number plate aspect.

Optometrists can do much to help in the present situation. The observation that many drivers fail to wear their corrective spectacles when at the wheel suggests that, in addition to the need for more forceful advice from the optometrist, opportunities exist for attempting to persuade patients to have a spare pair of distance spectacles in the cars glove box. As Taylor points out, patients need to be advised of the potential problems associated with any particular visual disability, so that, depending on its severity, they may either adjust their driving behaviour or notify the DVLA.

The vexed question inevitably arises as to how the optometrist should react when, in spite of advice to the patient that he or she should notify the DVLA, it appears unlikely that the patient will take action. Although most cases will require a referral for medical advice, and the general practitioner will try to resolve the situation, this step may not occur. Smith1 advises The decision then has to be made as to whether the public interests duty to report the patient outweighs the duty of confidentiality to the patient. This is a decision not to be taken lightly and (should be reached) only after consultation with the practitioners professional body. Such actions should always be capable of justification.

This issue of CE Optometry contain much food for thought. Population trends are such that the typical driver will soon be the older driver. The optometrist will have an important role in helping such drivers to cope with the visual problems of the road and, inevitably, in advising some individuals that it is time to end their driving career.

Reference
1. Smith PA. Drivers vision: advice in the consulting room. Optometry Today 1995 January 16; 35(1): 28-29.