Some have said no dot. My experience (with aging eyesight: glasses or contacts) is that I shoot much better with a RDS. I have both open and closed emitters. I have not seen any need for a closed emitter. The size of the dot does matter though. For a small carry gun that would need to be deployed quickly and under stress, I would recommend a larger dot. (i.e. the 6moa dot on the 407k) It is easy to see/acquire with both eyes open. (Glasses, no glasses, or contacts) I find that smaller 2moa dots are fine for larger guns, but for smaller, up close and personal guns, the 6moa seems much better. Put the dot on the target and pull the trigger!! Easy and fast with a little training, which should be done with any setup.