When any impaired driver's field of view encounters brighter light then the eyes of the driver might not be able to adapt the light easily so the driver might feel temporarily blind.
This is caused when a very bright light suddenly falls on the eyes of the driver and the eyes are not able adjust too much of bright light all at once.
In case of a impaired drivers the case is more worse as it can stay for a more time period and they are temporarily blinded.
