"When observing his work, I noticed the pronounced divergence of the eyes in all his paintings," explained the study's author, Christopher Tyler, a research professor at City University in London and the Smith-Kettlewell Eye Research Institute in San Francisco. .
When analyzing the direction of the look in six probable self-portraits of da Vinci (two sculptures, two oil paintings and two drawings), Tyler discovered that part of the work showed signs of exotropia, with the eyes looking at an external angle.
Not all six works were self-portraits, but Da Vinci specified in his own writings that any portrait work by a painter reflects the painter's appearance.
Tyler evaluated the condition of the eye by drawing circles on the pupils, lilies and eyelids in each painting and measuring their positions. When he turned the measurements into an angle, the results showed that da Vinci had a tendency to exotropia, with one eye turning -10.3 degrees outward when relaxed. But the master artist could turn his eye to a straight alignment when focused.
Tyler believes that Da Vinci's left eye was affected by the condition, but it's not easy to be sure.
Exotropia eye misalignment, a form of strabismus, affects about 1% of the The world population, he said.
Da Vinci's exotropia allowed him to see the world from a different angle. "What I was seeing would look more like a flat canvas than a three-dimensional screen for us," Tyler said; this made it "easier to translate things to the canvas".
This condition contrasts with the regular vision of your other eye to help you develop a solid understanding of three-dimensional objects. Tyler said that this ability made it possible for most of Da Vinci's artworks to have the precise shading for which he is known.
The study observed that the different direction and size of the students in some of the works of Da Vinci can be interpreted as anisocoria, a condition in which one student is larger than the other. But Tyler said that this is "very unlikely." Rather, he believes that Da Vinci was using this description to show his experience of one eye by seeing more clearly than the other.
Dr. Julius Oatts, assistant professor in the Department of Ophthalmology at the University of California, San Francisco, described the findings as interesting. "There are many uncertainties about whether the images really represent Da Vinci and whether they represent the eyes realistically," noted Oatts, who was not involved in the study.
Tyler said the artist "is such a historically convincing figure that it is very interesting to explore the roots of his genius."