There is. And the obvious conclusion is that the harm is completely negligible.
There is absolutely no possibility of physiological damage from light exposure (some people still seem to be kicking that idea around), and the chance of causing the pilot to be unable to operate the aircraft due to distraction or damaging night vision is very low.
Next up I will give you basic landing training and you get to land a small aircraft at night all by yourself with a laser pointed at the cockpit. You are of course allowed to use the remaining eye.