For small children, I have drawn closed eyes (like the cup of a u) w/little j's for the eye lashes. I used ink pens or markers. that way there is not a choking hazard. For 5 yrs or older, I have used 2 colors of buttons sewn on top of each other. Than used a glue like fray check on the top of the button as well as the back.
Hope that helps.
Billie G