I must disagree with closing an eye, if you shoot instinctive there is no need and your depth perception will suffer, besides if a person is right handed and left eye dominant or vise versa, the dominant eye will be in play when you switch hands. While I do not agree that you have to switch, unless there is something wrong with your bow arm or drawing arm, if you want to, do so, just takes practice as with anything it will become natural for most. I am not one of the most, I am strongly right handed and left eye dominant and tried to switch but have always shot right handed and am a good shot, killed a bunch of critters and see no need to switch after over 45 years of doing this.