These "subtle problems" could lead to "rapid fatigue of the eyes" and dreaded "loss of 3D viewing," and it could get much worse: "loss of place when reading or copying, reduced reading comprehension, poor grades and increased frustration at school" are all possible nightmares come true if your kids show signs of the "3Ds of 3D viewing" (no, really) -- discomfort, dizziness or lack of depth -- while playing 3DS. How else will you know, if you don't buy one for them immediately?
But what if your kids are too young? After all, Nintendo has warned that children under six shouldn't be playing the handheld in 3D mode. About that ... You see, "children younger than 6 can use the 3DS in 3D mode," the AOA assures, "if their visual system is developing normally." Listen to your family eye doctors, your kids could sure use a 3DS. "In moderation," of course.