ABSTRACT
The eye is a sophisticated imaging device. It forms real images of real
objects that compose the outer scene on the light-sensitive surface
of the retina. Moreover, to obtain a sharp image this system must
be stigmatic and the outer scene must be focused at the fixed plane
where the photoreceptors are located. The visual acuity, whatever
the position of the observed object, is ensured thanks to the process
of accommodation, that is, by the adaptation of the optical power
processed by the lens. From an optical point of view, the anterior
segment of the eye is mainly composed of the cornea and the lens.
The cornea serves three main functions: protection from the outer
environment, transmission of light (light must enter the eyeball and
reach the retina to be detected by the photoreceptors) and refraction
of light (the cornea is responsible for two-thirds of the eye’s optical
power).
