Scott fires pure, ruby-tinged concussive energy from his eyes that is constantly projected whenever he opens them. Commonly referred to as an “Optic Blast,” this beam of energy can have incredible force behind it, and just as a regular human can focus their eyes, Scott can focus his own to manipulate the power and size of the aperture of the blast, allowing him to do everything from slice objects (and foes) with thin beams of intense force, or blanket a wide area with concussive energy at long ranges. They can be incredibly powerful, capable of leveling Sentinels or punching holes in mountains, or they can be relatively mild, knocking over or otherwise incapacitating his enemies—or, as we see in X-Men ‘97‘s opening episodes, allow Scott to do things like soften an aerial landing or glide himself around a battlefield.

This also means that, no, they are not heat rays. The kinetic energy that Scott’s beams are made of does not directly generate heat, but because of its sheer concussive force (and because the beams are, in decades and decades and decades of comics, occasionally described and presented as if they do generate heat—writers and artists are people, and therefore occasionally imperfect!), they can cause burns or ignite sparks through the amount of friction generated by a blast, especially a sustained one. It’s not a heat vision like Superman’s, though, and never has been.