title: A scanning focimeter to measure peripheral lens powers.
abstract: A special device adapted to a Nikon projection vertexometer permits the power to be measured in the periphery of ophthalmic lenses. The marginal power can be measured with respect to the vertex sphere. Various values of the vertex sphere radius can be obtained with this instrument. The characteristics of this modified focimeter are described in this paper.
mesh_terms: D005139:Eyeglasses; D055095:Optics and Photonics / Q000295:instrumentation*; D009907:Optometry / Q000295:instrumentation