On the subject of depth perception, if you can see the plane clearly, ie it's not fuzzy then your eyes are okay. Think about this: your eyes are only a couple of inches apart but the plane is at least a couple of hundred feet away. Depth perception is pretty much a guess over 50ft away.
The advantage an instructor may give you is experience of the field. He will know the correct landing approach to take and where the plane should be placed for each part of the pattern.