I think that answer depends on the eye doc you are going to. If he/she is someone used to doing adults only, doesn't understand your concerns and doesn't know how to accurately check a 4 year old for acuity, astigmatism and visual efficiency skills, then I'd say skip it. Go to someone who has experience with kids just like yours. Someone who focuses on vision and learning. So, ask how many kids your doc sees and what the typical exam for a 4 year old would include.