I was walking home from taking some photos one night about a month ago. Points of light in my photos had taken on star shapes (no surprise). If I understand things rightly, you get a star because the camera aperture is not perfectly round; and the number of points is determined by the number of aperture blades. Anyway, entering my apartment`s car park, I looked up at a street lamp and saw a many-pointed star. Then I thought about the stereotypical nativity scene, with a four-pointed North Star above baby Jesus. It got me wondering what creates the star effect we perceive with our eyes. Can anyone provide any illumination on this? With a street lamp, I guessed that the glass casing could be responsible. But what about stars in the sky? I also noticed that the stars I see emanating from given object don`t always have the same number of points. Another thought: the pupil in the human eye is controlled by two sets of muscles: circular, which contract to make the aperture smaller; and radial, which contract to make the aperture larger. Obviously, there`s a finite number of radial muscles. Shouldn`t that mean that the pupil isn`t perfectly round? If so, how many blades does the aperture have? The obvious question: is there any relation between nighttime light sources as stars and the shape of our eye`s pupil? Another question: as far as I know, people generally have imperfectly-symmetrical muscles all over the body. Does this apply to the eye too? I know there`s a condition where people have oval-shaped pupils. I wonder how this affects their visual perception. Finally, any suggestions for where can I read more about the human eye and how it relates to photography?