Was rare eye condition the secret to Leonardo da Vinci's artistic genius?

This oil painting of a young John the Baptist is believed to be Leonardo da Vinci's last painting. Its subject's eyes are not perfectly aligned, which University of London professor Christopher Tyler says suggests da Vinci may have suffered from strabismus himself. (Wikimedia Commons)

There could be a scientific explanation for why it seems like some of the world’s greatest artists saw things a little differently than most people.

Researchers have previously found evidence that Picasso and Rembrandt may have been affected by strabismus, the condition that causes eyes to cross and reduces depth perception.

Leonardo da Vinci may well be another name for that list, according to a new British study.

Christopher Tyler, an optometry and visual studies professor at the University of London, started looking at depictions of da Vinci to see if they showed the same consistent eye divergences seen in other renowned artists.

He told CTVNews.ca that finding source material was the biggest challenge he faced.

“The difficulty with da Vinci is there are so few established self-portraits or portraits of him,” he said Wednesday in a telephone interview from London.

Given the lack of artwork in which da Vinci was described as the subject, Tyler had to get creative. He studied a bronze statue created by da Vinci’s mentor, Andrea del Verrocchio, for which da Vinci is believed to have served as a model and which Tyler called the “most plausible” surviving example of his likeness.

“It has clearly divergent eyes,” he said. A similar second sculpture was also studied.

In addition, Tyler researched several of da Vinci’s works – a decision he says is backed by da Vinci’s own belief that artists subconsciously model their subjects to look like themselves.

“He himself makes the point that it’s very difficult to avoid doing that, if you’re an artist,” Tyler said.

Da Vinci wrote in his “Codex Atlanticus” that “[the soul] guides the painter’s arm and makes him reproduce himself, since it appears to the soul that this is the best way to represent a human being,” according to a translation cited in Tyler’s study.

Tyler found that all seven pieces he examined showed their subjects’ eyes to be slightly askew. On average, one pupil was angled about 10 per cent away from where it would be in a non-cross-eyed person.

While Tyler admits that his evidence is circumstantial, he is not the first researcher to try and connect famous artists’ works with their appearances. Researchers from Harvard Medical School used a similar method to suggest Rembrandt may have had strabismus.

Margaret Livingstone and Bevil Conway noted in 2004 that having eyes out of alignment would have meant Rembrandt was stereoblind – which would have harmed his depth perception and therefore made it easier for him to depict three-dimensional scenes on two-dimensional surfaces.

Tyler sees the same phenomenon potentially occurring with da Vinci.

“[Strabismus] would perhaps explain his great facility for depicting the three-dimensional solidity of faces and objects in the world and the distant depth recession of mountainous scenes,” he said in the study, which has been published in the journal JAMA Ophthalmology.

According to the American Association for Pediatric Ophthalmology and Strabismus, an estimated four per cent of Americans have strabismus.