A British researcher believes the Renaissance artisan, Leonardo da Vinci, had an eye condition called strabismus, or “lazy eye”, providing him a different sense of depth when it came to painting.
His specific strabismus was an exotropia, in which one eye moves outward, out of sync with the unaffected eye.
Study author, Christopher Tyler, professor at City University of London and the Smith-Kettlewell Eye Research Institute in San Francisco, states, “One of the things he is most famous for is his 3-D modeling [in which he adds] up to 30 layers of shading to get the subtle gradients.
“This is the kind of cue you don’t notice if you have full 3-D vision, but [it] can become more apparent if you shut — or shut off — one eye.”
Interestingly, in one of his famous works, the Mona Lisa, one could see a swelling of her left hand.
She was the wife of Francesco del Giocondo, and appears to have a lump under her second finger. This could have been a ganglion cyst or a giant cell tumor of the tendon sheath.
Strabismus affects 4% of Americans, many of whom do not feel any visual deficits. Some, however, may infer a strain of the field of vision, and some may incur double vision.
Treatment may include glasses, eye therapy, and surgery.