Source:http://linkedlifedata.com/resource/umls/id/C0181612
UMD: Ophthalmic measuring instruments designed to measure the optical characteristics of lenses (e.g. spherical power, cylinder power, cylinder axis, prismatic power, lens diameter). The instruments measure how the light is refracted as it passes through the lens. Lensometers can be manual or automatic. Lensometers are used mainly to determine whether the lens characteristics and the prescription match.