Driving is an activity undertaken by most adults in the UK. Indeed, in an eye examination it is often assumed that all active adults over the age of 17 years will be a driver. The current regulations for vision of drivers in the UK are formulated to comply with Annex III of the 2nd EC Directive on Vision and Driving, 91/439/EEC. Each member state of the EC interprets this directive in its own way, though all must apply the minimum standard, and there has been a feeling for some time that there needs to be a greater degree of harmonisation to ensure a more commonly applied set of standards.
Working groups were set up by the EC Driving Licence Committee in 2004 to consider these issues. The terms of reference for the groups were:
- Member state representatives will be asked to put forward a medical and/or scientific expert in the relevant field for all working groups to be established
- Working groups shall review the available evidence on the diagnosis, prognosis of and treatment for the disease
- They shall further review practicable methods of identifying traffic risk groups and shall propose, where applicable, preventive measures and procedures
- To identify any significant gaps in knowledge and to define questions which might enable these gaps to be filled
- Based on existing practices and viewpoints in member states to formulate and propose recommendations to the driving licence committee to enable the latter to adapt Annex III to Directive 91/439/EEC to scientific and technical progress.
A report was issued in 2005 which made various recommendations.1 Agreement has now been reached2 on the implementation of recommendations as the new minimum EC standard, and the member states of the EC now have 12 months to implement any required changes. There will need to be a considerable amount of discussion before this can happen in the UK as the new regulations provide no guidance on the methodology or acceptable reference ranges of some parameters.
The basic standard for a driving licence still remains visual acuity. If there is any doubt about the standard being reached, then an assessment shall be carried out by a 'competent medical authority'. This assessment shall look at visual acuity, field of vision, twilight vision, glare and contrast sensitivity, diplopia and 'other visual functions that can compromise safe driving'.
Interestingly, the requirement for twilight vision is not new, having existed in the previous Annex. This appears to have been implemented in the UK by asking for a consultant ophthalmologist's opinion in appropriate cases.
The major change in the revised Annex is the requirement in cases of doubt to look at glare and contrast sensitivity. There are several tests that could be used, but as yet it is not known how these functions will be assessed. It is for each member state to consider whether, for example, a specific acuity score on a specified contrast sensitivity chart will be required, or be left as a matter of opinion from a suitably qualified person.
Group 1 licences
These are the licences issued to car drivers and motorcyclists. It should also be noted that some existing Group 1 licence holders are also entitled to drive light commercial vehicles and minibuses. The level of binocular acuity specified remains at decimal 0.5 (6/12), which is currently implemented in UK legislation as the number plate test. The recommended ('should have') binocular visual field stays at 120 degrees horizontally, but is now also specified as being a minimum of 20 degrees above and 20 degrees below fixation as is currently implemented in the UK. There are also additional recommendations that there should be a minimum of 50 degrees of horizontal field on each side of fixation, and that there should be 'no defects' within a radius of the central 20 degrees. It will be interesting to see how the visual field recommendations are implemented in the UK.
One obvious point of discussion is that there is no requirement in the Annex for a specific number of points to be tested within the central 20 degrees.
But perhaps the biggest change for Group 1 drivers is the expansion of the 'exceptional case' rules. Currently, drivers who do not meet the visual field requirements in the UK can apply to be assessed as special cases if the underlying medical condition is considered to be non-progressive, and that there has been adaptation to the defective visual field. The new Annex now also includes persons with reduced visual acuity in the 'exceptional case' rules, but with no statement as to what should be considered a minimum permissible level. Reference back to the recommendations of the EC working group is expected, where 0.3 is given as the lowest acceptable acuity in exceptional cases. As a principle, the EC working group reports remain the background against which all the Annex revisions, and the uncertainties, should be read.
Functionally monocular drivers must have the same visual acuity and field of vision as specified above. The previous requirement for a decimal acuity of 0.6 has been removed. A 'competent medical authority' must certify that adaptation has taken place to monocularity. It is recommended that there should be an adaptation period for drivers who are newly monocular when no driving should be allowed. Although six months of adaptation is given as a suggestion, the period may well be longer in cases where, for example, the vision is suddenly lost in a healthy eye, rather than loss of vision in an eye with previously poor vision. A specialised assessment by 'vision and driving experts' should then take place before driving is allowed again.
The provision for regular eye examination of progressive disease conditions (eg diabetes, glaucoma), is remained in the new Annex.
Group 2 licences
Drivers of heavy commercial vehicles, buses etc need a Group 2 licence, and these have more stringent requirements than those for Group 1.
Here the visual acuity requirements have been made less demanding for those applying or renewing such a licence. The requirement is now for a decimal acuity of at least 0.8 in the better eye and 0.1 in the worse eye. Furthermore, there is a limit of +8.00 in the power of any spectacle lens used to reach these acuities, although contact lenses are permitted at higher powers. There is no limit as to the power of negative spectacle lenses that can be worn. This new requirement would require a legislative change if implemented in the UK, as the new permitted acuity of 0.1 (6/60) in the worse eye replaces a previous more stringent value of 0.5 (6/12).
Additionally, there is also a new requirement that new applicants or applicants for renewal of a Group 2 licence should not have 'impaired contrast sensitivity' or diplopia.
The visual field recommendations are also more demanding for Group 2 drivers, than for Group 1 drivers, though in this case, they are less demanding than the previous Group 2 field standard. The horizontal binocular field is specified as 160 degrees, with a minimum of 70 degrees on either side of fixation and 30 degrees above and 30 degrees below. No defects within a radius of the central 30 degrees.
As with Group 1 drivers, an adaptation period and re-assessment is recommended where there is a 'substantial loss of vision in one eye'.
Discussion
As mentioned above, the new minimum specified visual acuity for a Group 2 driver will require a legislative change before it can be implemented in the UK. But there are also implementation issues of the other sections of the Annex which the Department for Transport and the DVLA will have to consider.
Currently, the DVLA issues operational guidance3 as to the UK implementation of the EC regulations. This will require amendment as to how the new Annex is to be implemented, particularly in relation to contrast sensitivity and glare recovery measurement. The issue of 'exceptional cases' in relation to visual acuity is particularly tricky. Should there be a minimum level of binocular acuity? Should aids for acuity such as BiOptic telescopes be allowed? Who constitutes a 'competent medical authority' for each test?
Over the next 12 months these and other issues will need to be resolved before the UK implements the new regulations. Any changes in driving rules are likely to cause extensive discussion and debate.
Acknowledgements
The author is indebted to staff at the DVLA medical branch for checking the accuracy of the draft of this article.
References
- New standards for the visual functions of drivers. Report of the Eyesight Working Group, Brussels, 2005.
- Commission Directive 2009/112/EC of 25 August 2009 amending Council Directive 91/439/EEC on driving licences. Official Journal of the European Union, Vol 52 p 26, August 26, 2009.
- At a glance guide to the current medical standards of fitness to drive. Drivers' Medical Group, DVLA, Swansea, September 2009 (www.dft.gov.uk/dvla/medical/ataglance.aspx).
? Dr Colin Fowler is a member of the 'Secretary of State for Transport's Honorary Medical Advisory Panel on Driving and Visual Disorders'. Any opinions expressed are his and do not necessarily reflect the views of the panel