An optical device for measuring the transmission and diffusion of a tissue of the front segment of an eye, includes: a light source an optical collimation system for directing the collimated light beam towards a tissue of the front segment of an eye to be characterized an optical mire placed on the optical path between the optical collimation system and the tissue an optical imaging system capable of receiving a light beam transmitted by the mire and the tissue and capable of forming an image of the mire on an image detector and an image processing system capable of calculating a modulation transfer function for the tissue from an image of the mire through the ocular medium. The optical mire includes a set of alternately light and dark angular sectors radially distributed from a central point. Different image processing methods for extracting a function representing the transmission and diffusion characteristics of the tissue are described.
