It reminds me of when you go to the eye doc and they numb your eyes. At first I think "My eyes! I can't feel my eyes!" then after I get used to it I start thinking "Wow, this is cool."
I wonder: What happens when Superman gets dust in his eyes? It wouldn't hurt him, but would he start blinking a lot? Tears are just salt water, so could he have super tears? Interesting questions.