The law requires HGV drivers to be in reasonably good health in order to legally operate commercial vehicles on public roads.
When attending an HGV medical exam, the doctor shall complete the paperwork (DVLA D4 form) that is then submitted to the DVLA. The Doctor cannot assess whether you are fit to drive a commercial vehicle, they simply complete the D4 medical examination form. The DVLA makes the decision on whether you are fit to drive.
You will be required to attend such a medical every time your licence is due for renewal.
What to expect at an HGV Medical: