Color blindness is not colorblind, as it appears to afflict Caucasian boys at three times the rate of African-American boys, according to a new study.
Among children 37 to 72 months of age, a total of 5.6% of Caucasian boys had color blindness compared with 1.6% of African-American boys, reported , of the University of Illinois at Chicago, and colleagues.
Asian boys had the second highest percentage at 3.1%, followed by Hispanic boys with 2.6%, they reported online in Ophthalmology.
Action Points
- The prevalence of color vision deficiency in preschool children is highest in non-Hispanic whites and lowest in black children, researchers found.
- It is also much more common in boys than girls, as the red and green pigment genes involved in color vision are located on the X chromosome.
The overall prevalence of was about 2% -- translating to 59 boys and four girls out of 4,005 children who were able to complete the test. Color blindness is generally much more common in boys than in girls, since the red and green pigment genes involved in color vision are located on the X chromosome.
"To our knowledge, no previous population-based studies have investigated the prevalence of color vision deficiency in a multi-ethnic cohort of preschool children younger than 6 years," researchers said.
, a pediatrician with the The University of Kansas Hospital in Kansas City, Kan., told 51˶ that the study confirms what she and her colleagues see in clinical practice.
"The study is a reminder to screen more closely those groups with a higher incidence of color blindness," she said.
The recommended age to begin vision screening -- 3 years -- is endorsed by the , the American Academy of Ophthalmology, and the .
For their analysis, Varma and colleagues recruited the children from Los Angeles and Riverside counties in California as part of the population-based (MEPEDS).
When researchers compared older (61 to 72 months) with younger (37 to 60 months) children, they found no difference in prevalence of color blindness, nor did they find a difference between younger and older kids within any ethnic group.
They noted that testability was high by the age of 4 and increased linearly with age:
- Ages 30 to 36 months: 17% were testable
- Ages 37 to 48 months: 57%
- Ages 49 to 60 months: 89%
- Ages 61 to 72 months: 98%
The divide along ethnic lines is also reflective of findings in older children, Varma and colleagues pointed out. Data from the CDC's National Health Examination Survey from the early 1960s found a 3.8% overall prevalence of color blindness (about 900,000 children affected). Among boys, race appeared to be significantly related to the presence of color blindness: 7.4% for whites versus 4% for blacks.
The corresponding study in conducted in the latter half of the 1960s found an overall prevalence of 4.3% (again about 900,000 children affected), but the difference between white and black boys was not significant (7.7% versus 6.4%).
An earlier collaboration between MEPEDS and the the Baltimore Pediatric Eye Disease Study (BPEDS) also found .
Varma and colleagues noted that their study has some strengths, including "the large MEPEDS population-based cohort and the fact that standardized color vision testing was administered to the children by eye care professionals."
Disclosures
The study was supported by the National Eye Institute and Research to Prevent Blindness.
The authors disclosed no relevant relationships with industry.
Primary Source
Ophthalmology
Xie JZ, et al “Color vision deficiency in preschool children: The Multi-Ethnic Pediatric Eye Disease Study” Ophthalmol 2014; DOI: 10.1016/j.ophtha.2014.01.018.