Abstract
It is important to screen for acquired or hereditary color vision defects as early as possible. Color vision is a critical part of the early learning experience, and children who have color deficiencies may have difficulties compared to their peers if there is color-based schoolwork. It becomes important for career interests/goals for older children as some jobs may require normal color vision. Hereditary red-green deficiencies are X-linked and therefore affect approximately 8% of males and less than 1% of females. Acquired color vision defects and blue-yellow defects are rare in the pediatric population; therefore, these conditions will be discussed minimally in this chapter. Infants are able to discern color by 2-3 months of age, but accurate color naming may not develop until 4-6 years of age. Screening tests are sensitive, fast, and easy to administer. If a deficiency is suspected through screening, further testing must be evaluated in order to determine the type and severity of the color vision defect. Color vision is typically tested starting at age 3 years and up.
TopGeneral Guidelines For Pediatric Color Vison Testing
- 1.
Typical test distance is 75cm (Carlson, 2004; National Research Council (US) Committee on Vision, 1981), but the examiner can permit young children to move closer to better engage visual attention or facilitate a motor/tracing response.
- 2.
Color vision screening is more accurate when conducted in natural daylight or with a CIE Standard Illuminant C lamp (Birch, 2001). These lamps mimic average daylight’s spectral distribution. Incandescent stand lamps are strongly discouraged during color vision screening as deutans will often perform better and may even pass screening testing when completed in this lighting.
- 3.
Present the color vision test plates perpendicular to the line of sight.
- 4.
Be prepared to shift to a developmentally easier test method. For example, if a school age child unexpectedly cannot correctly name numbers, shift to a tracing method. Note that the font used for some color vision numbers can be confusing to children.
- 5.
Binocular color vision testing is standard. Consider monocular color vision testing if ocular disease is suspected.
- 6.
It is important that children do not touch the pages in the color vision test books and the pages are not exposed to direct sunlight as it ruins the printed color. If the tracing method is employed, have children trace with a small paint brush or cotton tip applicator.
- 7.
If the clinician suspects the child is failing the test because of poor cooperation, consider asking the parent to administer the test.
- 8.
It is helpful to have printed information available for children who test positive for color vision deficiency.
- 9.
It is common for parents to need reassurance that their child is not color-blind.
Key Terms in this Chapter
Ishihara: A pseudoisochromatic plate test that screens for red-green deficiencies using predominantly numbers that may be more difficult for younger children or illiterate patients.
Hardy-Rand-Rittler (HRR): A pseudoisochromatic plate test that can classify both red-green and blue-yellow defects, as well as the severity. It has child friendly shapes.
Waggoner: Dr. Terrace L. Waggoner, renowned color vision expert who has developed both print and digital pseudoisochromatic plate color vision tests.
Pseudoisochromatic Plates (PIPs): A category of color vision tests containing colored dots in a mosaic pattern.
Red-Green: The most common inherited color vision defect grouping both protan and deutan defects together.
Farnsworth Munsell: A type of hue discrimination arrangement test using colored discs in a gradual color changing sequence. The Farnsworth Munsell 100 (FM100) is typically used in older children or adults due to the length of the test.
Color Vision Test Made Easy (CVTME): A pseudoisochromatic plate test that is typically used in preschool age children due to its easily recognizable shapes and pictures. It only classifies between normal and abnormal color vision, not the type of severity.
Farnsworth: A type of hue discrimination arrangement test using colored discs in a gradual color changing sequence. The Farnsworth Panel D 15 (FD15) is the shorter version (compared to the Farnsworth Munsell 100).
Anomaloscope: The gold standard for color vision testing using an anomaloscope, a device in which knobs are used to match two colored areas in both color and brightness. Well-known brands in the United States include Nagel, Neitz, and Pickford-Nicolson.