Ibn-al-Haitham developed:

Explanation

Optics is the correct answer. Ibn al-Haitham made groundbreaking contributions to the field of optics. His most famous work, "Kitab al-Manazir" (Book of Optics), is a comprehensive study of light, vision, and optics. In this work, he discussed the nature of light, the formation of images, the anatomy of the eye, and the principles of reflection and refraction. Ibn al-Haitham's work laid the foundation for the understanding of optics in medieval Europe and had a profound influence on later scientists, including Roger Bacon and Johannes Kepler.