For if the opening of the pupil were too large then when we had to look at overly brilliant objects, the rays of these objects converged on the retina would soon dissipate its delicate fibers, as we see the sun's rays converged by a magnifying glass bum what is exposed at their focus, or at least they would diminish the delicacy of the fibers of the retina in such a way that we would no longer see anything in a dark or badly lighted place.