I can't believe my eyes!

What do you think? Does a person, who wears glasses that are thicker in the middle compared to its edges, have difficulties in seeing far away or close by objects?

a) Glasses, which are thicker in the middle compared to its edges, are made for people with difficulties to see far away objects. So that's why these glasses must belong to Michael's grandma.

b) Glasses, which are thicker in the middle compared to its edges, are made for people with difficulties to see close by objects or they help with reading. So that's why these glasses must belong to Michael's grandpa.

c) The glass of real glasses is equally thick; in the middle and at the edges. That's why Michael cannot say whose glasses he has found.