Lensometer

Abstract: A spectrometer (S) is incorporated to a conventional lensometer (L). The spectrometer (S) includes a uniform extended light source (50) including a light source having visible and ultraviolet emission and an extending integrating sphere (52) including ultraviolet transmission. In the preferred embodiment, an Ebert spectrometer (S) is utilized, although other spectrometers may be used as well. Light is emitted from the light source (50) through the spectacle lens to be tested to a spherical reflecting surface (65). Upon reflection, the light is incident to a grating (70), retro reflected to the spherical surface (65) and thereafter reflected for incidence to a charge coupled device (75) for analysis of the generated spectrum. The system is provided with a slit (60) and a field stop (56) dimensioned so that through all ranges of lenses expected to be tested within the designated tolerances of sphere, cylinder and prism, the spectrometer (S) sees only and always a portion of the uniform extended light source (50).

Abstract: A series of units for manual use or for use in combination with a standard lensometer for evaluating the parameters of soft or flexible contact lenses. The units comprise convexly disposed hemispheres of graduated diameters comprising rigid or semi-rigid material, each of which has a round central aperture and is marked on its convex surface with a series of concentric calibration circles. In preferred form, each of the convex hemispheres is integrally formed with a flat supporting plate, with the convex side protruding and the concave interior having an internal dimension which accommodates any conventional lensometer or similar lens testing instrument. The soft lens whose curvature is to be measured is placed by trial and error on successive inspection and measuring units until the curvature matches or falls between two units of known radii. The unit including the lens is then attached to a stop of the vertometer or other optical instrument for reading the refractive power, or can be held in conjunction with a hand magnifier or biomicroscope to determine other lens parameters, and for inspecting the surfaces and edges of the lens.

Abstract: A device is provided for use with a lensometer which will adjustably hold a ground lens as it is moved until its optical center coincides with the line of sight of the lensometer. The device is provided with two spaced apart, fixed markers and a line passing therethrough will indicate a horizontal line passing through the optical center of the lenses when they are fitted into the frames of the eye spectacle. The device is also provided with a movable marker, movable precise amounts in accordance with the prescription of an individual patient for a particular spectacle frame to indicate the geometric center of that lens when mounted in that spectacle frame and for that particular patient.

Abstract: In illustrative implementations of this invention, a lensometer includes a small aperture camera for capturing an image of light that travels from a display surface, through a subject lens and to the camera. One or more computers are programmed to perform calculations that take the image as an input and that compute, for each respective region in a set of regions of the subject lens, a refractive attribute of the respective region.