Lens clock definitions

Lens clock

1) Ophthalmic equipment
Found on https://www.crosswordclues.com/clue/lens-clock

A lens clock is a mechanical dial indicator that is used to measure dioptric power of a lens. It is a specialized version of a spherometer. A lens clock measures the curvature of a surface, but gives the result as an optical power in diopters, assuming the lens is made of a material with a particular refractive index. A typical lens clock is calib...
Found on http://en.wikipedia.org/wiki/Lens_clock

lens clock

Synonym for Geneva lens measure ... A device for measuring the radii of the curvature of a spectacle lens. ... Synonym: lens clock. ... Origin: Geneva, Switzerland ... (05 Mar 2000) ...
Found on http://www.encyclo.co.uk/local/20973