Health and Fitness

Color blindness tests and types of color blindness Screening tests

A color blindness test is a way an optometrist determines if you have a color vision deficit, commonly referred to as color blindness.

If you think you may be color blind, see your eye doctor. (Don’t have one yet? Click here to find an optometrist nearby .)

There are two types of color blindness tests:

  1. Screening tests to find out if you can distinguish colors
  2. More detailed quantitative color vision tests that can detect both color vision deficits and determine the type and severity of color blindness


Screening tests for color blindness

The most widely used screening test for color blindness is the Ishihara color vision test.

The test is named after its creator, the Japanese ophthalmologist Shinobu Ishihara (1879–1963),
who developed a special procedure and first published its description in 1917.

Eye doctors use Ishihara plates to screen patients for color vision problems. A person with red-green color blindness may not notice the red number in this example.

The Ishihara Color Perception Test is a brochure with a circular (or “plate”)
element on each page made up of many dots of different colors, brightness, and size.

Seemingly scattered, the colored dots are actually positioned in such a way
that a person with normal color vision will easily notice a single or two-digit number among them.
But a person suffering from color blindness will not be able to see the number depicted
or will see a number that is different from the number that a person with normal color vision saw.

The full version of the Ishihara color perception test contains 38 plates. Abbreviated versions of the test, containing 14 or 24 “plates”, are more often used as screening tests
during a comprehensive eye examination.

During the test, a person usually looks through Ishihara’s “plates” in normal
daylight indoors and wearing ordinary glasses prescribed by a doctor…
Since the main task of the Ishihara test is to recognize and identify the numbers in the image,
this method of checking may be less reliable for very young children.

The term “pseudo-isochromatic tables” is often used to describe color images in the Ishihara color perception test. This name is due to the fact that some colored dots in the image may initially appear the same (“iso”) color (“chromatic”) with the surrounding dots.

But this perception of “sameness” is deceptive (“pseudo”), and a person with normal color vision will immediately notice the difference and see the “hidden” number in the array of dots.

Since the introduction of the Ishihara Color Sensing Test, many other medical device manufacturers have developed similar screening tests for color blindness using pseudo-isochromatic tables.

For example, the computerized ColorDx color perception test (Konan Medical) is a self-assessment and self-assessment application available for download on tablet computers.

According to the company, in addition to detecting genetic, the ColorDx test is able to detect color vision deficiencies that have developed at some point in life in glaucoma, multiple sclerosis, diabetic retinopathy, macular edema, and other diseases, as well as color vision problems associated with prolonged the use of drugs and other substances.

Quantitative tests

To analyze color blindness in more detail and/or to determine how accurately
a person is able to perceive and distinguish shades of colors,
The most famous of these is the Farnsworth-Mansell 100 Shades test.Expandable

The Farnsworth-Munsell 100 Hue Color Vision Test identifies and quantifies color vision problems. (Photo: Macular Pigment Research Group, Waterford Institute of Technology)

many small discs of different colors. There is a color control disc at the end of each tray.

in a booth that simulates natural daylight as closely as possible.
In addition, color discs should be replaced
at least every two years to prevent discoloration that can affect results.

The more close to the correct result in the disc sequence, the more accurate the test taker’s perception of color.

Thus, the test “100 shades” is not only able to determine whether a person is color blind but also determines the type and severity of color blindness.

An abbreviated version of the 100 Shades Test – the Farnsworth-Mansell D15 test –
The D15 test, like the Ishihara color vision test, not quantify the degree of color blindness in a person.

Who needs a color blindness test?

Anyone whose profession requires accurate color perception should pass the color blindness test. These include electricians, graphic designers, designers, technicians, and some industrial and marketing workers.

The extent to which affects the performance of a person’s duties at work largely depends on the requirements for the color perception of his position and on the degree of color vision deficiency in a person.

Since color blindness is present from birth, most color blind people are unaware of their color vision deficit and do not believe that this significantly interferes with their daily life.

Although there is no cure for color blindness, in some cases, specially tinted contact lenses can improve the ability of color blind people to perceive differences between certain colors.

Online color blindness tests

You can find many online tests on the internet. Most of them are variations of the Ishihara screening test with varying degrees of color presentation quality.

Since accurate color is critical to the accuracy of any blindness test, the results of online color vision screening tests should not be trusted. For the most accurate results, see your optometrist and have a color blindness test under the supervision of a qualified professional under proper lighting using standardized test materials.

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