As Syaoran 小狼 pointed out, both "見える" and "見(ら)れる" may be used as "to be able to see". I guess this is what you want to ask about in this question, but nobody has explained it so far.
When translated as "to be able to see", "見える" and "見(ら)れる" are different in that the former implies that (A) you are able to see even if you neither make any special efforts nor do you want to see, while the latter (B) you have to do something, or you need special condition to be able to see/watch.
Strictly speaking, "見れる" has to be "見られる", which is what we call "ら抜き言葉 (dropping the ra)". Even native Japanese use the former incorrectly, but you don't have to be so nervous about it in the case above or outside of exams.
Note that there are cases where you can't use "見れる" instead of "見られる".
"見られる" also means (C) "can be taken/recognized/observed" and (D) "worth watching". Both also might be just translated as "be able to see", but you have to know these meanings to use it correctly.
Here are some examples.
# [O] stands for "OK", and [X] "NG".
(A) We can see other people's faults well.
# We can see without special effort.
(B) You can watch TV if you pay the fee.
# You need to pay to watch.
(A & B) You can see outside better from the upstairs.
# "You can see better from the upstairs" & "you need to go upstairs to see better"
(C) This is the tendency that can be recognized/observed with the younger generation.
(D) Lately, there's no TV program worth watching.