If you want to see if the blade is warped by eye, you'd need to look end on. I often eyeball it by opening the razor as if to shave. Then, with the tang end of the blade closest to me, I close one eye and look down the blade. I usually look from the left side and then the right (as opposed to looking down), and I only look from an angle that is slightly off.

You might have to play with which eye you use to "sight" and what part of the razor you focus on; you do need to have a decent depth of focus for this to work out.

Other than that, as others suggested, get a large piece of something-you-know-is-flat or color the edge with a marker and hone for a bit to see if it all goes away.