The deep fovea as a focus indicator.
D000818:Animals; D003201:Computers; D005584:Fovea Centralis / Q000033:anatomy & histology / Q000502:physiology*; D006801:Humans; D007909:Lenses; D008266:Macula Lutea / Q000502:physiology*; D008954:Models, Biological; D014785:Vision, Ocular