Recently, a war broke out on social media over the divisive X-Man Cyclops. The nature of the divide stemmed from his mutant abilities, which some insisted were a form of heat vision -- a debate egged on by writer Gail Simone, presumably with tongue in cheek.
So let’s set the record straight. Does Cyclops have heat vision? No, he does not. His eye beams are specifically noted in official sources as being “heatless.”
How do his power work then? Well, that’s a question with a long, confusing answer.
First, if Cyclops’ eyebeams aren’t made up of heat – like the red beams that shoot from Superman’s eyes – then what are they? They’re force. Rather than a heat blast, his is a concussive blast that pushes things away as if they being shove or punched very hard.
One thing Cyclops’ powers do actually have in common with Superman’s is that they are activated by solar energy. Cyclops’ cells actually absorb the ambient energy around him, including but not limited to solar energy, and uses it to fuel his powers.
How exactly that energy fuels his powers is a bit confusing and has been explained in different ways in the past. The original Official Handbook to the Marvel Universe claimed that Cyclops’ eyes had actually been replaced by portals to a dimension of pure force, and that the energy was simply spilling out from that dimension through his eyes, and that the energy he absorbed kept the portals open.
Later editions of the Handbook corrected this to say that the ambient energy Cyclops absorbs is what fuels his eye blasts directly, but online sources, including Marvel’s own website, still state that Cyclops’ eyes are inter-dimensional portals, leaving the matter up for some debate.
Either way, solar energy is vital to Cyclops' power, as there have been times when a prolonged lack of sunlight has caused his powers to fizzle out completely.
Cyclops should be capable of controlling the flow of energy through his eyes – or closing his eye portals if you prefer – but instead, the force beams are constantly in an “on” state.
This began as the result of a head injury as a child and was believed to be a permanent physical trauma. However, Joss Whedon’s Astonishing X-Men series revealed that the damage from the head injury did actually heal and that the reasons Cyclops powers won’t turn off are psychosomatic, brought on by the pressure of being chosen by Professor X to be leader of the X-Men at a young age, a fear of losing control and hurting others, and the emotional trauma of his childhood.
Cyclops can block his eye beams by simply closing his eyes. The reason that his eye beams don’t simply tear his eyelids off is that Cyclops’ body has a personal psionic field that covers his entire body, making it immune to the effects of his own eye blasts.
When Cyclops came to the Xavier Institute, he discovered that the material ruby quartz resonates at a similar frequency to his own psionic field. By wearing glasses or a visor made out of ruby quartz, Cyclops is capable of keeping his eyes open and keeping his eye beams in check.
The depiction of Cyclops’ powers is sometimes inconsistent, and that applies especially to the X-Men movies.
While adult Cyclops’ powers were shown pretty consistently, depictions of young Cyclops in X-Men Origins: Wolverine and X-Men: Apocalypse have shown the remnants of whatever Cyclops blasts with his eye beams catching fire, implying that there is some heat involved.
While this is likely an oversight by the filmmakers, it could be head-canon as having to do with extreme friction, or perhaps have something to do with the intensity of Cyclops’ powers when he was young before he trained as an X-Man and learned to control them better.