Abstract: A system for determining with essentially continuous variability, wave aberrations originating in an eye of a subject, according to the visual perception of said subject.

Abstract: A refractometer and a method for measuring the refractive index of a lens, wherein a thin insert in the form of a pad of a flexible transparent material attached to a rigid transparent sheet, is lightly pressed onto a surface of the lens under test, such that the pad surface effectively acquires the same profile as the lens surface. The focal length or power of the lens is first measured without the insert, and the measurement is then repeated with the insert positioned first in contact with one surface of the lens, and then in contact with the other surface. The use of equations derived from the classical lens formula then enables the refractive index of the lens to be easily and quickly determined. The apparatus and method also enables the measurement of the refractive index of lenses of low power.

Abstract: This invention discloses an apparatus for providing optical information regarding spectacles in which are mounted first and second lenses, the apparatus includes a spectacles mapper operative to compute a map, within a single coordinate system, of at least one optical characteristic over both of the two lenses, and a spectacles analyzer operative to provide an output indication of optical information related to the map.A method for providing optical information regarding spectacles is also disclosed.