Birds, bees and Claude Monet: How the famed artist could see in ultraviolet just like some animals

Most people would see water lilies as white.

But after he had the lens on his left eye removed at the age of 82, Claude Monet started painting the flowers with a blue tinge. The operation had enabled the artist to see - and subsequently to paint - in ultraviolet.

This insight and others are all explained in Color Uncovered, a sumptuous iPad app that takes the reader through a range of subjects on colour including: optical illusions, food dyes and why dogs shouldn't drive (they can't see stop signs).

Humans have three types of pigments tuned to blue, yellow, and green light. Each pigment responds to a certain colour.

But the same pigment can also react weakly to close colours on the spectrum. The pigment tuned to blue sometimes responds weakly to violet and weaker still to ultraviolet. Most people will never experience what Monet saw because their lenses filter out UV rays.

Monet's condition is known as 'aphakia' - the absence of the lens of the eye. It is rare for babies to be born without a lens, they are mostly removed for medical reasons later in life.

Monet had developed cataracts and as his lenses got worse he complained to friends that he saw everything in a fog. His painting suffered until he had the lens removed.

Light could now stream through uninterrupted, and without the lens acting as a filter, so too the UV light.

Birds, bees and other animals have pigments tuned to UV light. For example, most humans wouldn't be able to differentiate between the males and females of certain butterfly species. But to UV sensitive eyes like Monet's, they look completely different as the males have bright patterns to attract a mate.

Similarly many flowers contain ultraviolet patterns that cannot be detected by the human eye, to attract bees for pollination.

http://www.dailymail.co.uk/sciencetech/article-2131608/Claude-Monet-How-famed-artist-ultraviolet-just-like-animals.html

'Cat-Eye' Boy Video Said To Show Chinese Child Who Sees In Dark

According to a news reel from China, a young boy there possesses the ability to see in the dark. Like a Siamese cat's, his sky-blue eyes flash neon green when illuminated by a flashlight, and his night vision is good enough to enable him to fill out questionnaires while sitting in a pitch black room — or so say the reporters who visited Nong Yousui in his hometown of Dahua three years ago.

The footage of Nong and his strange-looking eyes originally surfaced in 2009; it got little attention at the time, but is now making a splash all over the Web. If the boy really does have a genetic mutation that confers night vision, then he would be an interesting subject for analysis by vision scientists, evolutionary biologists, and genetic engineers alike — but does he? 

The experts we shared the video with say Nong does have unusually colored irises considering his ethnicity, but he's not the next step in human evolution.

Night vision is made possible by a layer of cells, called the tapetum lucidum, in the eyes of cats and other nocturnal animals. This thin layer is a "retroreflector" — when a beam of light hits it, it reflects the light directly back along its incoming path. The reflected beam constructively interferes with the incoming light beam, amplifying the overall signal that hits the retina and enabling the animal to see in very low-light conditions. Retroreflection also causes cat eyes to flash when they are lit upon at night, and experts say Nong's eyes, if they are truly catlike, should do the same. [Red-Green & Blue-Yellow: The Stunning Colors You Can't See]

"It would be easy to test the boy’s eyes for retroreflection (eyeshine), which would be indicative of a tapetum lucidum," said Nathaniel Greene, a physicist at Bloomsburg University of Pennsylvania who has studied retroreflection.

Read on and see video:  http://www.huffingtonpost.com/2012/01/31/cat-eyes-boy_n_1244543.html