Landolt Test – All You Need To Know
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Have you ever seen a Landolt Test? Do you know who Edmund Landolt was? Do you know how the Landolt Test table is used and for whom the Landolt Test is intended? Have you ever heard of the Landolt rings?
If the answer is no, don’t worry. Today we will learn all these concepts, and at the end of the article, we will be able to download a Landolt Test in PDF to do a little test at home.
What Is The Landolt Test?
The Landolt test is used to measure visual acuity. Its creator was the ophthalmologist Edmund Landolt, hence its name Landolt Test, also known as Landolt C, Landolt Ring, Landolt Broken Ring, or Japanese visual test.
The Landolt C is the most widely accepted reference optotype used in the laboratory for visual acuity measurement tests.
Who was Edmund Landolt?
Jacques Rodolphe Edmund Landolt was an ophthalmologist born in Kirchberg, Switzerland, on May 17, 1846, and died at the age of 79 in Paris on May 9, 1926.
His penchant for eye health began early, thanks to the fact that the father of a schoolmate was a butcher and provided him with the eyes of slaughtered animals so that he could study and examine them.
In 1869, Edmund Landolt obtained a medical doctorate from the University of Zurich specializing in ophthalmology. In 1872, he made several trips to complete his training. He was a student of Herman Snellen and Franciscus Cornelis Donders in Utrecht, among others, with whom he also worked in physiological optics before settling in Paris.
In 1874, he settled in Paris, working as an oculist at the Institut National des Jeunes Aveugles (National Institute for Young Blind People, the first school in the world for blind students).
Landolt founded a private ophthalmological clinic on Rue Saint-André-des-Arts in Paris known worldwide and was considered one of the most eminent ophthalmologists in France, co-directing with Émile Javal the Laboratoire d’Ophtalmologie at the Sorbonne.
In 1881, Landolt founded Les Archives d’Ophtalmologie with Photinos Panas and Antonin Poncet, in addition to conducting several investigations in the field of physiological optics and the functions of the ocular muscles.
Edmund Landolt is the author of nearly 400 scientific publications including: “‘Sur les causes de l’amétropie’, of 1877; ‘Leçons sur le diagnostic des maladies des yeux’, of 1877; ‘L’oeil artificial’, of 1878; ‘Manuel d’ophtalmoscopie’, of 1878; ‘Clinique des maladies des yeux’, of 1878; ‘Traité complet d’ophtalmologie’, ‘Tableau synoptique des mouvements des yeux et de leurs anomalies’ and ‘Rapport sur la question du strabisme’, of 1888; ‘Optotypes simples’, of 1889; ‘Précis de therapeutique ophtalmologique’, of 1895; ‘Nouveau optotype pour la détermination de l’acuit visuelle’, of 1899; ‘Des problèmes de diagnostique motilité oculaire’, of 1909, and ‘Examen des mouvements normaux et pathologiques des yeux’, of 1916.”
Edmund Landolt is primarily known for his publication of the Landolt’s Test or Landolt C and for being the discoverer of ‘Landolt’s bodies,’ which are: “Small bodies of indeterminate nature found between the rods and cones of the retina” (Stedman’s Medical Dictionary, p. 538).
As his obituary states: Edmund Landolt was “a link between the heroes of ophthalmology of an earlier generation and the specialists of the present day.”
How is the Landolt Test Chart Used? And How To Interpret The Landolt Test Results?
The method of use and system for calculating visual acuity with the Landolt test is the same as with the Snellen or Tumbling E test. (We recommend reading the article: Visual Acuity Test – Snellen Test for more detailed information).
The Chart comprises characters that become smaller and smaller as we move down the rows. The person performing the test must indicate which position the characters or optotypes are oriented.
In the same way as with the Snellen Test or Snellen’s E, with the Landolt Test, the measurement of visual acuity will be based on the last line perceptible by the person performing the test.
The Landolt C is an optotype standardized in most European countries to measure visual acuity.
The Landolt rings are the optotypes of which the Landolt test chart is composed. It is a circle that is not quite complete, similar to a C; the ‘missing’ piece of the ring is what the person performing the test has to identify.
The stroke and width of the Landolt ring are one-fifth of its outer diameter, and the edges of the ring break are parallel and of the same width as the stroke of the ring. Its main advantage is that it has only one element to differentiate, which is easy to measure.
The only difference we have found in the Landolt chart is that the test can be presented with four positions (up, down, right or left) or eight positions (with the intermediate positions in a 45º diagonal).
In both cases, the optotypes are presented randomly and in as diversified a manner as possible.
The Concilium Visual Functions Committee accepts both options as stated in the ICO 1984 visual acuity measurement standard. However, it prefers the four-position Landolt ring as the reference optotype.
For Whom Is The Landolt Test Intended?
The Landolt test is intended for use with children over 3 years of age who cannot yet read and who are asked to indicate which way the bitten piece of doughnut is facing.
The Landolt C is also used with people who do not know the Latin alphabet or have a problem identifying words or have some disability that prevents them from being able to speak.
Landolt Test In PDF
To do it correctly, we recommend that you read our article Snellen Test At Home, beforehand to know what you need to have closeby since the principles are the same in both tests.