It is the idea that not everything you see is the whole picture, and often there is more to the story that we don't see on the surface. For example, while someone might look happy and fine, underneath they are really distressed and hiding feelings and worries that they won't show. Saying that there is more than meets the eye shows it is important not to always take things how they seem.

There could be something else besides what we are seeing, something not obvious. The expression is an admonition to look beyond the superficial.

It should be the singular 'eye' not 'eyes' in this expression.

Not all answers are entirely obvious. It suggests that we look more deeply, for less than obvious causes The pithy expression, that tell us; "Read----Between---The---Lines" suggests precisely the same meaning. .

I think "there maybe more than you can see"