I trained a guy who was blind in one eye and couldn't see out of the other.
Never handled a pistol in his life. I was a little surprised when he asked me to help him pick something for HD/SD, and get him oriented and familiar with it.
We picked the XD with the laser package deal they offered. The intensity of the spot is what he thought helped him the most. In a few hours he could put the entire mag in the nines at seven yards. I have to conclude lasers are good help for some, especially those unfamiliar with firearms.