Quote - Eyes are round. Renders are flat projection, and not representative of how the images form on the retina, which is curved.

What you say is true, but I can't quite grasp how it is relevant to the Keystone effect, which was presumably the subject of your comment. It seems to me that focal plain of the eye being roughly a section of a sphere would mean that the hyperfocal distance is represented as a concave section of a sphere. But that's focus. Wouldn't the Keystone effect be related only to the incident angle (line of sight), which is invariant with respect to the shape of the image plain?