You should not be trying to get a sleep paralysis, because in this state you might have a hard time going out of body, it is, as the name suggests, you might just find yourself paralyzed and stay this way until the trance state come to and end, which is what happens for many people who have sleep paralysis (not everyone is able to go out starting from this state). Instead, what you should focus is on entering the trance state, the phase.
About the eyes, in reality that's a tricky question I would say, because you don't need to think of your eyes, but you can just "try/desire to see", and that's enough. However, it happens sometimes that you can actually open and close perfect "copies" of physical eyes when out of body. Anyway, I'd say that the only thing you should be concerned with, is to get practice in controlling your astral vision without interfering with the physical vision (without moving or tension of eyelids), and the same applies for all senses and movements that you perform when obe.