Currently, three-dimensional vision or stereoscopic vision is in fashion, from the most recent films, through mobile telephony to the most current devices used in clinical ophthalmology. It should be noted that this is not something “new”, because the interest in stereoscopic photography and binocular vision goes back a long time. It is necessary to know that human stereoscopic vision is achieved from two slightly different images in perspective from each eye, which the brain merges and combines creating the sensation of depth or three-dimensionality.
How is 3D used in ophthalmology?
Medicine has sought utility through stereoscopic photography and image analysis, especially in the field related to ophthalmology. For example, photographs of the optic nerve taken from different angles have been compared, obtaining a sensation of depth between the papilla and the neuroretinal ring, useful in glaucomatous disease. In our center we work with the best devices that include three-dimensional reconstructions of ocular structures, such as the latest generation PENTACAM topographer for corneal analysis and the OCT-3 2000D optical coherence tomograph, which offers both fixed and mobile three-dimensional images. which are especially useful in retinal pathologies. In specific cases, these types of images improve the diagnostic information allowing our doctors to more accurately assess the depth, profusion and location of the lesions in the fundus, with the aim of always offering the best technology to our patients.
But how did we get here?
In the Renaissance Leonardo da Vinci studied the visual system from an anatomical point of view and extensively examined perspective. Curiously, in 2012 a restoration study revealed that the copy of the Mona Lisa by Leonardo da Vinci that is exhibited in the Museo Del Prado is the oldest that exists, and thanks to this it is believed to have discovered the first three-dimensional portrait of the history. The German scientists Claus-Christian Carbon and Vera Hesslinger, from the University of Bamberg, analyzed the original work in the Louvre as well as the copy exhibited in Madrid. The result of his investigations proposes that both works could have been painted in the same studio and simultaneously, probably by a student close to the teacher with direct access to his works.
In the upper image, on the left, the work exhibited in the Prado Museum is observed first and then the original work exhibited in the Louvre. The image below represents a reconstruction of the position assumed by both artists.
Driven by the hypothesis that Leonardo had the insight to create both works from different perspectives, the German research team recalculated the position that the two painters supposedly maintained among themselves with respect to the model while working on the portraits. The analysis of trajectories between the reference points of both paintings revealed that indeed the two versions differ slightly in perspective, finding a horizontal distance of 69 millimeters from each other. This distance is close to the distance between the two eyes (62-64mm), which gives a slightly different perspective of the space with each eye, creating the feeling of depth. In their study, Carbon and Hesslinger say that if both canvases come together under cyan and red filters, the Mona Lisa takes on relief.
It should be noted that Leonardo painted this painting at the beginning of 1500, approximately 300 years before the stereopsis was officially defined by Charles Wheatstone in 1838.
Cristina Peña Betancor
Optician-Optometrist
CLÍNICA NIVARIA