Some drivers are required to undertake an assessment of their fitness to drive. This depends on the type of licence they have, their age, or whether they have a medical condition that may affect their ability to drive. Anyone who needs to do this will receive a letter outlining what's required.
All licence holders, regardless of age, must report a medical condition that could affect their ability to drive. They can do this when applying for or renewing their licence, or when the condition is diagnosed.
Commercial drivers are assessed when they apply for their licence or driver accreditation.