I feel like nothing would be able to survive an un-visored optic blast stare down, but what are Scotts limits?
Cyclops' force beams were measured by Iron Man to be almost 2 Gigawatts.
~Civil War: X-Men #4
Cyclops has shown the power of his optic blast by blasting through the walls of a hardened building, tunneling through solid rock, and blowing the top off a mountain. He has also been able to knock Thor's (the strongest current Asgardian) hammer out of his hands.
I can't be sure, this is just a long forgotten memory, but I believe that there were two beams, in the Mutant arsenal, that could cut Adamantium. Scotts optic blast, and Dazzlers laser projection at maximum output. Since Scotts blast only produce force and not heat that must be very powerful (when focused to pinpoint accuracy) indeed.