The largest refracting optical lens in the world measures 1.827m (5.99ft) in diameter. It was constructed by a team led by Thomas Peck (USA), at the Optics Shop of the Optical Sciences Center of the University of Arizona in Tucson, Arizona, USA, and completed in January 2000. It was built as a test for the secondary mirror of the 6.5m (21.3ft) MMT Telescope on Mt Hopkins, Arizona, USA.

The lens is made from fused quartz and weighs roughly 1000lb (450kg)