Numerical confusion errors in ishihara testing: findings from a population-based study.
OBJECTIVE
To describe the prevalence of numerical confusion errors in Ishihara testing in a representative sample of Australian children.


METHODS
Cross-sectional, population-based study.


METHODS
The Sydney Myopia Study examined a representative stratified random cluster sample of 1,741 children (aged 6 years) attending 34 schools in Sydney, Australia (response rate, 78.9%), including color vision tests in 1,735 children. Those with any color vision defects (n = 33; 1.9%; 97% boys) were excluded. Responses for each Ishihara plate were recorded.


RESULTS
Numerical confusion errors were made by 75.8% of children with normal color vision; there was no gender difference. Plates 3 and 7 were particularly prone to numerical confusion errors; 48.4% and 40.8%, respectively, of children misread these plates.


CONCLUSIONS
Numerical confusion errors in the Ishihara test were relatively common in children with normal color vision. The frequency of such errors could indicate an inherent deficiency in this commonly used test.
Cosstick
Michael
M
Department of Ophthalmology, Centre for Vision Research, Westmead Hospital, Australia.
Robaei
Dana
D
Rose
Kathryn
K
Rochtchina
Elena
E
Mitchell
Paul
P
D002648:Child; D003118:Color Perception; D003119:Color Perception Tests / Q000295:instrumentation*; D003117:Color Vision Defects / Q000175:diagnosis / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008297:Male; D009517:New South Wales / Q000453:epidemiology; D015995:Prevalence; D015203:Reproducibility of Results