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In 1922, a patent was filed for the first projection lensmeter, which has a similar system to the standard lensmeter pictured above, but projects the measuring target onto a screen eliminating the need for correction of the observer's
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One of five comprehensive instructional videos derived from the original Flash animation on the use of the Topcon lensmeter (vertometer). Produced by Dr Suzane
Vassallo with La Trobe University. These videos are also available
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produced the photographometer, an instrument designed to measure the intensity of photogenic rays; and in 1849 he brought out the focimeter, for securing a perfect focus in photographic portraiture. In 1876,
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in the instrument itself and reducing the requirement to peer down a small telescope into the instrument. Despite these advantages the above design is still predominant in the optical world.
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171:, and is often capable of marking the lens center and various other measurements critical to proper performance of the lens. It may also be used prior to an
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to measure the back or front vertex power of a spectacle lens and verify the correct prescription in a pair of
167:: sphere, cylinder, axis, add, and in some cases, prism. The lensmeter is also used to check the accuracy of
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of a convex lens. Troppman went a step further in 1912, introducing the first direct measuring instrument.
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to obtain the last prescription the patient was given, in order to expedite the subsequent examination.
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The parameters appraised by a lensmeter are the values specified by an
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Millodot: Dictionary of
Optometry & Visual Science, 7th edition
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16:
Ophthalmic instrument mainly used by optometrists and opticians
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lensometer (sometimes even known as focimeter or vertometer)
293:"Ophthalmology Glossary on Carl Zeiss Vision GmbH website"
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introduced a phakometer which was a similar set up to an
340:at George Eastman House Inc.: 1–2. Archived from
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196:which could measure the power and find the
60:A simple lensmeter cross sectional view.
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152:, if a special lens support is used.
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115:– Power drum (+20 and -20 Diopters)
338:International Museum of Photography
132:, is an optical instrument used in
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50:A Lensmeter in an Optical shop
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243:Corrective lens components
110:– Angle adjustment lever
321:, eds. (February 1952).
136:. It is mainly used by
336:(2). Rochester, N.Y.:
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65:– Adjustable eyepiece
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421:Measuring instruments
96:– Illuminated target
78:– Keplerian telescope
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416:Ophthalmic equipment
382:accessed 20 Jan 2009
268:"Vertometer. (n.d.)"
248:Abbe refractometer
169:progressive lenses
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120:– Prism scale knob
92:– Standard lens
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396:Lensometry basics
347:on March 12, 2013
315:Newhall, Beaumont
311:Solbert, Oscar N.
163:on the patient's
74:– Objective lens
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369:. Archived from
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323:"The Focimeter"
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299:on 12 May 2008.
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190:Hermann Snellen
185:Antoine Claudet
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173:eye examination
157:ophthalmologist
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101:– Light source
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87:– Unknown lens
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83:– Lens holder
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134:ophthalmology
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375:. Retrieved
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367:"Focimeters"
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342:the original
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297:the original
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276:. Retrieved
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138:optometrists
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105:– Collimator
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161:optometrist
39:Archive.org
31:Wikiversity
410:Categories
377:2010-01-30
278:2015-01-04
254:References
218:Lens clock
146:eyeglasses
69:– Reticle
233:Focometer
183:In 1848,
142:opticians
126:lensmeter
351:June 16,
212:See also
228:Diopter
179:History
35:Youtube
274:. 2009
345:(PDF)
330:Image
326:(PDF)
353:2014
140:and
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