[Cataract surgery: institutions, techniques and scientific models from Brisseau to Daviel]

The intellectual biography of Jacques Daviel (1693-1762) offers unexpected opportunities to recall fundamental steps in the history of scientific ideas, academic institutions and surgical techniques. Kepler had, in fact, ousted the crystalline lens from the full seat of the visual power to the refracting medium, but his work had no effect on the central core of the eye doctors' practice, namely, cataract surgery. Daviel's audacity, which was not to push down but to extract the lens with the cataract, brought the Keplerian revolution to a completion. In addition, physiologists and philsophers tried to befriend Daviel, and they made use of his exceptional manual dexterity to work out Molyneux's question, that is, the test of the man born blind who recovered his sight, which posed problems in the 18th century in the theory of knowledge.