ishihara test
C2 / Very low frequencyTechnical/Medical/Academic
Definition
Meaning
A specific type of colour vision test consisting of plates with coloured dots forming numbers or patterns, used to diagnose red-green colour deficiencies.
Any test for colour blindness using similar principles of colour confusion, or more loosely, the plates themselves. Can be used metonymically to refer to the process of screening for colour vision deficiencies.
Linguistics
Semantic Notes
The term is a proper noun (eponym) derived from the name of its inventor, Japanese ophthalmologist Shinobu Ishihara. It refers to a specific, standardized tool, not a generic colour blindness test.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences. Both use the same term. Spelling and terminology within the context of ophthalmology/optometry are identical.
Connotations
Identical technical connotations. The term is known primarily to medical professionals, vision scientists, and those who have been tested.
Frequency
Extremely low frequency in general discourse in both varieties. Its frequency is confined to specialist fields. No regional variation in frequency is noted.
Vocabulary
Collocations
Grammar
Valency Patterns
The optometrist administered [the Ishihara test] to the patient.The patient took [the Ishihara test].[The Ishihara test] revealed a protan deficiency.They diagnosed him using [an Ishihara test].Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “[No established idioms for this highly technical term]”
Usage
Context Usage
Business
Rare, except in occupational health contexts for jobs requiring normal colour vision (e.g., pilots, electricians). 'The job requires passing an Ishihara test.'
Academic
Common in optometry, ophthalmology, vision science, and psychology textbooks and research papers. 'The study used the 38-plate Ishihara test.'
Everyday
Very rare. May be used by individuals recounting a medical examination. 'At the eye doctor's, I had to look at those dotted number plates—the Ishihara test.'
Technical
The primary context. Standard term in clinical optometry and medical reports for diagnosing colour vision deficiencies.
Examples
By Part of Speech
verb
British English
- [Not applicable as a verb]
American English
- [Not applicable as a verb]
adverb
British English
- [Not applicable as an adverb]
American English
- [Not applicable as an adverb]
adjective
British English
- The Ishihara-style plates were effective.
- He underwent an Ishihara-type screening.
American English
- The Ishihara-style plates were effective.
- He underwent an Ishihara-type screening.
Examples
By CEFR Level
- The doctor showed me pictures with dots. It was a test for colours.
- I had a colour blindness test with the dotted number plates.
- During the medical, the optician used an Ishihara test to check for colour vision deficiencies.
- The study's protocol mandated that all participants pass the standard 24-plate Ishihara test to ensure normal colour vision.
Learning
Memory Aids
Mnemonic
Imagine a colourful HARa (HARA) painting by artist ISHI. The test uses colourful ISHI's HARA plates to test your eyes.
Conceptual Metaphor
TEST AS A REVEALER (The test reveals a hidden condition). COLOURS AS TRAPS (The dot patterns trap/confuse the colour-deficient eye).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid direct translation ('Тест Ишихары'). While understood by specialists, the more common generic term in Russian is 'тест на дальтонизм' or 'полихроматические таблицы'. 'Ишихара' is the specific type.
Common Mistakes
- Mispronunciation (e.g., 'Ishi-hara' with a hard 'h').
- Misspelling (e.g., 'Ishihira', 'Ischihara').
- Using it as a verb (*'I was Ishihara-tested').
- Using it generically for any vision test.
Practice
Quiz
What is the primary purpose of the Ishihara test?
FAQ
Frequently Asked Questions
It was invented by Dr. Shinobu Ishihara, a Japanese ophthalmologist, first published in 1917.
No, it is primarily designed to detect red-green colour deficiencies (protanopia and deuteranopia). It is not reliable for diagnosing blue-yellow (tritan) deficiencies or total colour blindness.
It uses pseudo-isochromatic plates—circles made of coloured dots of varying size and brightness. A number or path is embedded in a different colour, visible to those with normal colour vision but hidden or altered for those with a deficiency.
Not necessarily 'totally colour blind' (achromatopsia), which is very rare. Failing usually indicates a specific colour vision deficiency, most often a red-green confusion, which is a form of colour vision deficiency often called 'colour blindness' in common language.