Pierre-Louis Guinand (1748–1824) was a Swiss lens maker. who in the late 1700s came up with a breakthrough for making better quality and larger glass, and in time went on to teach a young Fraunhofer at Joseph von Utzschneider's (1763-1840) glassworks, and eventually started his own optical glass works. Guinand would supply glass for the Paris Observatory telescopes and also Cauchoix. He was a pioneer in the manufacture of optical glass for microscopes, telescopes, glasses and other optical instruments.