The whole surface of the tegument...

It is not in the straight line, but in the point of light - the point of irradiation, the play of light, fire, the source from which reflections pour forth. Light may travel in a straight line, but it is refracted, diffused, it floods, it fills - the eye is a sort of bowl - it flows over, too, it necessitates, around the ocular bowl, a whole series of organs, mechanisms, defences. The iris reacts not only to distance, but also to light, and it has to protect what takes place at the bottom of the bowl, which might, in certain circumstances, be damaged by it. The eyelid, too, when confronted with too bright a light, first blinks, that is, it screws itself up in a well-known grimace.

Lacan, Seminar XI 94