I've a creature that can focus CO2 laser through the len of the unique eyeball as means of self defense mechanism via natural selection. Now using the same natural selection process how can such creature prevent the laser from overheating the eye? Kindly use magic sparingly else face the wrath of my creature, it likes to put on a cape which do little to lessen the build up of heat. As usual answer that enables the species to shoot laser the longest duration wins.
The creature's eyes are completely transparent to infrared light.
Perhaps the creature can also see far into the infrared spectrum, thus eyes which are transparent in infrared light would be selected for. The CO2 laser is coherent light in the infrared spectrum (it can't be seen by humans), that light is not absorbed by the eyes, so no energy is absorbed, and the eyes don't heat up.
How about having large balloons around the eyes that contain some sort of liquid with low vaporization temperatures? The vapor can then be pumped through a biological equivalent of a condenser, and fed back to do more cooling work.
Blood, lymph, or some other liquid is pumped around the ocular lasing organs to absorb waste heat and then through a radiator fin, where the heat is radiated off through the high surface area.
Weather and temperatures would have an affect on how much the laser could be used without maxing out the radiator efficiency.
It could also work similar to a bat wing, where it extends out when needed to provide a large surface area, and then folds up to conserve warmth when it's not.
It's liquid cooling for the eyes.
It generates many little lasers in it's lung,
wich is cooled by the air it breathes, (also, there is good oxygen supply in the lung at all times) and uses optical wave guides to bundle and transport them to the eyes, where they only pass transparent parts.
optical wave guides