Donders reduced eye

Donders reduced eye

[′dän·dərz ri¦düst ′ī]
(optics)
An optical model used to simplify calculations of the size and position of images produced by the human eye, consisting of a convex refracting surface that separates air in front from water, with a refractive index of 4/3, behind, and having an anterior focal distance of 15 millimeters and a posterior focal distance of 20 millimeters.