#1 Contact lens First Prototypes

Leonardo da Vinci is frequently credited with introducing the idea of contact lenses in his 1508 Codex of the eye, Manual D, wherein he described a method of directly altering corneal power by either submerging the head in a bowl of water or wearing a water-filled glass hemisphere over the eye. Neither idea was practically implementable in da Vinci's time. He did not suggest his idea be used for correcting vision, as he was more interested in learning about the mechanisms of accommodation of the eye. Descartes proposed another idea in 1636—a glass tube filled with liquid placed in direct contact with the cornea. The protruding end was to be composed of clear glass, shaped to correct vision; however, the idea was impracticable since it made blinking impossible. In 1801, Thomas Young made a pair of basic contact lenses based on Descartes' model. He used wax to affix water-filled lenses to his eyes, which neutralized its refractive power. He then corrected for it with another pair of lenses. However, like da Vinci's, Young's device was not intended to correct refraction errors.