Are motorcycle helmet tinted visors illegal to use?

Motorcycle Helmets are essential safety equipment for all motorcyclists. Indeed, it is against the law to ride a motorcycle without being thus equipped, but, are they illegal to use?

On paper, a visor on any helmet has to have 100% clear visibility. This means any visor darker than that is forbidden from use

But, why is it forbidden?

The reason why is to determine who is behind the visor, more so if the rider’s eyes can also be seen. This is to allow for eye contact with other road users, especially car drivers.