The human eye functions just like a camera. However, it’s extremely more sensitive, more delicate and highly advanced. Well, except for slow motion. Nature didn’t equip us with that. The resolution of the human eye is estimated to be 576 megapixels. The retina, the thin layer of tissue that lines the back of the eye on the inside, contains two types of photoreceptors: rods and cones. The are around 120 million rods and up to 7 million cones in your retina. The cones, which are the ones responsible for color sensitivity, allow you to distinguish as many as 10 million colors.
You have to remember, though, that the combination of colors you see still depends on a primary part of the eye: the lens. By default, the lens on your eye filters out UV ray, making it impossible for us to see them with the naked eye. But this is probably for a good reason. First, it protects our eyes from the permanent damage of UV rays and it allows us to see sharper images. Some animals, however, have evolved to see UV with the naked eye. Spiders, mice, lizards, bees, and butterflies can see in UV without any issues. This allows them to see more details than we could.
Cataracts is a condition in which your lens becomes too cloudy, which leads to vision loss. In order to fix this problem, surgeons remove the defect lens and replace it with an artificial one to help see better. Watch the procedure in the following video.
During the surgery, you’re under local anesthesia and you’re too frightened to think straight, which is why you might not even notice when your lens is being removed. Specially that it’s done incredibly fast! However, Claude Monet (1840–1926), a painter who develop cataracts in 1920s, agreed to have his lens completely removed at age 82! The surgery took place in 1923.
“With his lens removed, Monet continued to paint. Flowers remained one of his favorite subjects. Only now the flowers were different. When most people look at water lily flowers, they appear white. After his cataract surgery, Monet’s blue-tuned pigments could grab some of the UV light bouncing off of the petals. He started to paint the flowers a whitish-blue.” ~ Carl Zimmer
“Even with the lens removed (a condition known as aphakia) the patient can still see, as the lens is only responsible for about 30% of the eyes’ focusing power. However, aphakic patients report that the process has an unusual side effect: they can see ultraviolet light. It is not normally visible because the lens blocks it. Some artificial lenses are also transparent to UV with the same effect. The receptors in the eye for blue light can actually see ultraviolet better than blue. Military intelligence is said to have used this talent in the second world war, recruiting aphakic observers to watch the coastline for German U-boats signalling to agents on the shore with UV lamps.” ~ David Hambling
The world would look very different in UV for sure! For instance, the males and females of some butterfly species might look identical to the naked human eye, but they are actually very different to UV-sensitive eyes. Scientists tested this and found that the males display bright patterns in order to attract the females. Take a look at the pictures below.
So, it appears that removing the lens from our eyes might give us a supervision, but it would destroy our retina in the process and prevent us from seeing sharp images. I’m sure somewhere somehow someone may have invented cool glasses that can help us see in UV without damaging our eyes. Finally, I’m going to leave you with this cool video, which shows people applying sunscreen as seen with a UV camera.