Getting clear on Descartes's theories of visual depth perceptio

In the Optics (1637), Descartes advanced five means of depth perception. Some commentators suggest that he employed geometrical reasoning, invoking a homunculus; while others suggest that these are causal accounts. In the Sixth Set of Replies (1641), Descartes discussed depth perception specifying that judgments are involved and referred back to the Optics account. Some claim that he changed his views between the Optics and Replies, relinquishing his causal accounts. Others argue that the Replies account is at odds with a major tenet of his philosophy whereby all ideas are transparent to the mind. Berkeley established his groundbreaking theory of depth perception in An Essay Towards a New Theory of Vision (1709) largely as a response to what he claimed are Descartes's "geometric accounts". Berkeley's position is predicated on a rejection of a particular version of Descartes's accounts whereby distance outwards is calculated using the distance between our eyes and the inclination of the two optic axes.;There is no such geometric account in Descartes; it is a straw man of Berkeley's invention. Descartes did not appeal to a homunculus in any of his accounts. He held an occasional-causal theory of perception that coheres with his theory of God's concurrent powers. He employed mechanical models in three of the five means of depth perception that are instances of a moving gland model. The latter is a sophisticated circuitous model where the soul (mind) has a role to play: our volitions to obtain particular visual achievements enter into a physiological process that centers on the pineal gland. When these models fall short for long distances, Descartes employed a judgmental model in the fifth means that relies on enumerative induction and natural signs. Certain aspects of Descartes's theories are comparable to certain aspects of contemporary theories in vision research. He did not change his views on depth perception between the Optics and Replies. His motive for the Replies was to defend an epistemic claim about judgments of the intellect versus the senses which prompted him to focus on the fifth (judgmental) means. The Transparency Thesis is not violated in the Replies account.