More than a million Brits could be driving with medical conditions that they haven't declared to the DVLA. There is an extensive list of pre-existing conditions that drivers are expected to declare to the DVLA and many of them aren't related to eyesight.

The DVLA lists almost 200 conditions that they should be made aware of by drivers and it includes things like depression, blood pressure, diabetes and OCD, to name a few. Drivers may also need to contact the DVLA if they develop new conditions or disabilities. Additionally, there are some one-off incidents that they may need to be made aware of as there is a chance it could impact your driving in the future. Drivers should also declare if an already-stated condition worsens or changes. A list of these conditions has been published on the agency's website and drivers have been encouraged to check the list to see if there is something they need to declare to the DVLA. 

Declarations of these conditions, of which there are a total of 189, can be completed using a paper form or online on the DVLA's website. 

The DVLA then might contact your GP or arrange for a medical assessment before making a decision regarding your licence.

There are then a multitude of decisions the DVLA can make, including a reduction in the time before a person needs to renew their licence or the requirement to apply for a new license. 

Additionally, they can demand that drivers immediately surrendoer their licences, which drivers can appeal. If a driver who has not declared their medical condition can face legal action of they are involved in an accident.