No, he had dark markings around his eyes and nose bridge before and the further darkening represents sage mode; same as it was with naruto, same as it was with Jiraya.
Also reptilian eyelids indicate that he can still see. Reptiles have eyelids just like any other animals. Crocks and other reptiles have a second set of eyelids so they can physically see when they are underwater.
p.s. Snakes can't blink or close their eyes because they lack movable eyelids.
edit 2:
If Snake sage mode is anything like Frog sage mode, who's molding the Chakra? Or is that a totally invalid point right now with all the bullshit Kishimoto is pulling out of his ass. Maybe it's just a perk of being evil, you hax everything.
Also if they are anything alike, wouldn't any disturbance by the Sharingan throw his chakra control out of wack and we get a Kabutoru statue.....