Having worked with lasers...
Anything below 1mW is deemed eye safe, and relies on the natural blink reflex to protect the eye. I also think that lasers of this power would not be much of a distraction at any distance.
Anything above that should be controlled. i.e. not for sale to general public, and classed as firearms, perhaps in a similar way that RIFs (Realistic Imitation Firearms i.e Airsoft weapons) are. In the UK such items already require importers and purchasers to be members of clubs and have an annual database recorded membership.
In relation to 'welding mask windscreens' it could work, or perhaps more achievable - glasses using that technology which could be worn during T/O & landing phases. Whilst they would protect the eyes from permanent damage, they would still leave you blind while they are active. I suppose a G/A or climb could be performed IFR?