Posted by: courtneygrapperhaus | February 1, 2016

Common Optical Instruments


Lensometer External eq6405

Used for:  Verification and prescription of eyeglasses. Used to orient and mark uncut lenses as well as check the accuracy of progressive lenses.

History:  First designed in 1912 by Troppman.

Other Names:  Focimeter, Vertometer, Lensmeter



Used For:  Measuring the curvature of the cornea (determines extent of astigmatism).

History:  Invented by Hermann von Helmholtz in 1851

Other Names:  ophthalmometer



Used for:  Seeing inside the fundus of the eye. Helps determine health of retina, optic disc and vitreous humor. There are 2 types:  Direct & Indirect. Direct produces an upright/unreversed image. Indirect produces an inverted/reversed image. Often used after dilation of the pupil by use of a mydriatic (i.e. tropicamide).

History:  Created in part by Charles Babbage in 1847 and by Hermann von Helmholtz in 1851.

Other Names: funduscope



Used for:  Measuring the radius and curvature of rigid contact lenses



Used for:  Shines a light into patient’s eyes to observe reflection off retina. While moving light across pupil, doctor observes reflex of the eye and adjusts trial frame “to neutralize the reflex” (Wikipedia).

History:  Created by Jacob Copeland in the late 1920’s (patent filed in 1926)

Slit Lamp


Used For:  Providing a magnified view of the eyes structures in detail. Allows doctors to diagnose a variety of eye conditions.

History:  In 1911 Alvar Gullstrand created a “large reflection-free ophthalmoscope” that evolved into the Gullstrand Slit Lamp by Vogt Henker in 1919. Several improvements have been made throughout the years, with the latest major change made in 1996.



Used for:  Measuring intraocular pressure (evaluates a patient for risk of glaucoma).

History:  “In the latter part of the 19th century von Graefe developed the first instrument for measuring intraocular pressure in 1865. The first reasonably accurate instrument was the Maklakoff applanation tonometer of the late 19th century. Schiötz developed an indentation tonometer that was widely used throughout the world during the first two thirds of the 20th century. Goldmann’s applanation tonometer of 1950 began the era of truly accurate intraocular pressure measurement. It is still the most widely used tonometer in the world. ” (



Used For:  General examination light for checking pupil reflex. Preferred overpenlights due to its stronger intensity.

Visual Field Analyzer

Visual Field

Used For:  Measures peripheral vision in detail to screen for, diagnose and various medical conditions, including glaucoma and strokes.



Used For:  Detecting a patient’s blind spot and changes in visual field.

History:  Invented in 1857 by Herman Aubert



Used For:  Measuring the distance between pupils for fitting eyeglasses. The digital design eliminates measuring errors and allows for precise measurement of a patient’s pupillary distance (PD).

Other Names:  PD Meter


  • Wikipedia
  • US National Library of Medicine National Institutes of Health

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