If you have normal vision, your eyes are not covered, and you are in a well-lit area, then opening your eyes is a necessary and sufficient condition for seeing.
true or false?

true

Explanation:

When your eyes are not covered and you are in an area with good lighting, then opening your eyes would certainly be a necessary thing to do to be able to see and this makes your vision to be normal.

According to Leo Gross, you can have a normal vision if you are 20 feet away from a particular spot and you see what a normal person sees on that same spot. There is the Snellen chart one is also expected to read in that position, so maintaining a normal vision means someone has 20/20 vision.