What machine did Leonardo da Vinci design for grinding lenses?

Leonardo da Vinci designed a lens-grinding machine for shaping optical lenses.

His notebooks contain studies of optics and mechanisms for working curved surfaces. A lens-grinding machine would use controlled rotation and abrasive material to shape glass more consistently than hand work alone. The design reflects Leonardo’s interest in improving instruments through mechanical precision.

Leonardo’s optical investigations included the behavior of light, vision, mirrors, and lenses. These studies were scientific as well as practical: he wanted to understand how images were formed and how optical devices could be made more useful.

The machine should not be confused with a telescope. A lens grinder makes or polishes optical components, while a telescope is an assembled viewing instrument. Leonardo designed many mechanisms on paper, and surviving drawings do not show that every one reached production.