Editing Ishihara test (section)

{{Short description|Color perception test}}
{{More citations needed|date=December 2023}}
{{Use American English|date=March 2021}}
{{Use dmy dates|date=April 2021}}
{{Infobox medical intervention
| Name        = Color perception test
| Image       = Ishihara 9.svg
| Caption     = Example of an Ishihara color test plate. The number "74" should be clearly visible to viewers with normal color vision. Viewers with [[red–green color blindness]] will read it as "21",<ref>{{cite book |last1=Bonewit-West |first1=Kathy |last2=Hunt |first2=Sue |last3=Applegate |first3=Edith |title=Today's Medical Assistant - E-Book: Clinical & Administrative Procedures |date=18 June 2014 |publisher=Elsevier Health Sciences |isbn=978-0-323-29180-4 |url=https://books.google.com/books?id=Xc7sAwAAQBAJ&dq=Ishihara+chart+%2274%22+%2221%22&pg=PA389 |language=en}}</ref> and viewers with [[monochromacy]] may see nothing.
| ICD10       =
| ICD9        = {{ICD9proc|95.06}}
| MeshID      = D003119
| OPS301      =
| OtherCodes  = 
| HCPCSlevel2 =
}}
The '''Ishihara test''' is a [[color vision test]] for detection of red–green [[color blindness|color deficiencies]]. It was named after its designer, [[Shinobu Ishihara]], a professor at the [[University of Tokyo]], who first published his tests in 1917.<ref name="ishihara1917">S. Ishihara, Tests for color-blindness (Handaya, Tokyo, Hongo Harukicho, 1917).</ref>

The test consists of a number of '''Ishihara plates''', which are a type of [[pseudoisochromatic plate]]. Each plate depicts a solid circle of colored dots appearing randomized in color and size.<ref>{{cite web|last=Kindel|first=Eric|title=Ishihara|url=http://www.eyemagazine.com/feature/article/ishihara|work=Eye Magazine|access-date=3 December 2013}}</ref> Within the pattern are dots which form a number or shape clearly visible to those with normal color vision, and invisible, or difficult to see, to those with a red–green color vision deficiency.  Other plates are intentionally designed to reveal numbers only to those with a red–green color vision deficiency, and be invisible to those with normal red–green color vision. The full test consists of 38 plates, but the existence of a severe deficiency is usually apparent after only a few plates. There are also Ishihara tests consisting of 10, 14 or 24 test plates, and plates in some versions ask the viewer to trace a line rather than read a number.<ref name="ishihara">{{cite book |last1=Ishihara |first1=Shinobu |title=Tests for Colour-Blindness |date=1972 |publisher=Kanehara Shuppan |url=http://www.dfisica.ubi.pt/~hgil/p.v.2/Ishihara/Ishihara.24.Plate.TEST.Book.pdf |access-date=17 June 2020 |archive-date=8 December 2020 |archive-url=https://web.archive.org/web/20201208160704/http://www.dfisica.ubi.pt/~hgil/p.v.2/Ishihara/Ishihara.24.Plate.TEST.Book.pdf |url-status=dead }}</ref>