Which part of the eye is known as the first refracting body?

The cornea is known as the first refracting body of the eye primarily because it is responsible for bending (refracting) the light that enters the eye, significantly contributing to the eye's overall focusing power. When light enters the eye, it first encounters the cornea, which has a curved surface that refracts the light towards the center of the eye. This initial refraction is crucial because it helps to direct light onto the retina, where the visual information is processed.

The crystalline lens, while also involved in refraction, works in conjunction with the cornea. It fine-tunes the focusing of light and adjusts for distance vision but is not the first point of refraction. The fovea centralis is a part of the retina, not involved in bending light; instead, it is responsible for high-acuity vision. The iris primarily controls the amount of light entering the eye but does not participate in the refraction of light. Thus, the cornea's role as the first refracting body is vital for the visual process.