Earlier quoted context omitted.
Except that everyone has different visual acuity and different distance they use the same devices at, and in the end, "retina" means nothing at all. But this is exactly the type of marketing Apple is good at, though "retina" is probably not the most successful example.
If your "visual acuity" is so good that you can see the pixels of a retina-branded display from the intended viewing distance, you might need to be studied for science.
20/10 is rare but can easily be corrected to with glasses or contacts.
You also left that "intended viewing distance" hanging there, without at all acknowledging what that is at a minimum?