But "Magevision" is a form of sight. Unlike Detect Magic, which is projecting a 60-foot cone to "ping" things, Arcane Sight only targets you. It's modifying your vision to be able to see octarine (not literally, but analogously), and your Arcane Eye sees "exactly as you would see if you were there."
I think you may have confused Line of Sight with Line of Effect. Arcane Eye doesn't provide Line of Effect--you can't Detect Magic through it, as Detect Magic is still going from your head to the 60 feet in front of it--but it does provide Line of Sight, or (by definition) you wouldn't be seeing with it.