What did Johannes Kepler contribute to the study of light and vision?

Johannes Kepler made foundational contributions to the study of optics and vision, primarily through his 1604 work, Ad Vitellionem Paralipomena. His key contributions include:12

• Theory of Vision: Kepler provided the first correct scientific account of how vision occurs. He proposed that the pupil acts as a diaphragm and that the lens of the eye focuses light to form an inverted image on the retina.123
• Point-by-Point Analysis: He introduced a revolutionary analytical method for optical problems, treating an extended object as a collection of individual points, each emitting rays of light in all directions.43
• Geometric Theory of Lenses: Kepler developed a geometric theory of lenses, which provided the first mathematical explanation for how eyeglasses correct vision and how telescopes function.412
• Telescopic Design: In his work Dioptrice (1611), he described a new type of telescope—now known as the Keplerian telescope—which utilized two convex lenses.12