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An instrument to measure the power and cylindric axis of a spectacle lens.
Synonym(s): focimeter, vertometer
[lens + G. metron, measure]


(len-zom′ĕt-ĕr) [ lens + -meter]
A device that measures the refractive power of a lens.


An optical instrument for determining the vertex power, axis direction and optical centre of an ophthalmic lens (Fig. F8). The instrument can be either manual or automated. Syn. Lensometer (a tradename); vertexometer; Vertometer (a tradename). See lens measure; neutralization; back vertex power.
Fig. F8 Focimeter (Shin Nippon)enlarge picture
Fig. F8 Focimeter (Shin Nippon)
References in periodicals archive ?
Lensometer measurements [lambda], [mu], and [alpha] become matrix entries in (3) and (4).
The lenses then are taken to the lensometer, and the optical centers are dotted for proper placement of the "block." The lenses then are "edged" and safety-beveled to prevent flaking and sharp edges.
The outputs from a keratometer or a lensometer are very closely related to eigenvalues and eigenvectors of an appropriate matrix.