Yes, early identification of learning difficulties is critical. Not only are basic skills acquired in early grades, but socialization is also affected by delayed learning. A child will be perceived by peers as different if skills lack, and also may acquire a poor self image if education lags.
I think the idea of checking eyesight and hearing is excellent. These are primary barriers. Often, though, learning style is the barrier. Educators should be aware of the wide variety of information processing styles among students. Addressing this will often lead to filling in the gaps.