One of the enduring commonalities across most human societies is the belief that our eyes are a window into the immutable truth of the universe. Eyewitnesses are accorded special status in trials, despite repeated studies demonstrating how fallible such on-the-scene reports can be. The idea that sight conveys reality is enshrined in everything from dusty myths and sacred texts to modern-day cop shows. As a result, it’s equal parts unsettling and interesting when we get a glimpse of how fluid our shared capability of vision can be.

Former Air Force Officer and engineer Alek Komar has spent a considerable amount of time detailing how his color vision changed following major cataract surgery. Cataracts are known to have a detrimental effect on color perception, but in Komar’s case, he didn’t just regain his old acuity: The Crystalens implant he received has given him the ability to see into the ultraviolet spectrum. While friends and family were initially skeptical of such claims, Komar secured the help of an HP engineer with access to a Monochromator; a device capable of projecting light in 10nm wavelength increments. Test results confirmed his perception. Anecdotal evidence indicates that he’s not the only Crystalens patient to see ultraviolet wavelengths following the procedure.

The image above is Komar’s simulation of what UV light looks like to him on surfaces where the rest of us just see black. The glow we typically associate with ultraviolet blacklights is caused by fluorescence, which is defined as the emission of light in the visible spectrum from a substance that’s absorbed other electromagnetic radiation.

Komar’s case is interesting for multiple reasons. It’s a demonstration of how modern medicine can change what we think of as “natural” vision by altering the lens. It’s also a small window into how tetrachromats — animals with four types of cone cells —- may see the world. Humans are trichromats; we have three types of cone structures in our eyes. In the picture above, we would see the upper flower — a bird, we think, sees the lower. Interestingly, there’s a chance that some humans are tetrachromats. Women who carry a copy of the OPN1MW gene on one X chromosome and OPNMW2 on the other may possess four separate types of cones rather than the usual three.