Color vision is one of the most important factors of human vision. Ear
ly detection of color vision malfunction in children is of utmost impo
rtance, allowing parents and teachers to take appropriate and timely m
easures for children's future professional orientation. A cohort of 30
0 children aged 4-6 years (49-86 months) were examined by color vision
testing and divided into three age groups of 4-5, 5-6 and >6 years. T
heir ability to name the fundamental spectral colors and read Ishihara
's pseudoisochromatic plates was recorded. The results obtained are pr
esented in tables and figures. Data analysis showed the youngest group
of children to be unsuitable for such testing of color vision. Numeri
cal data revealed considerable percentage deviations as compared to th
e older groups. In addition, a great difference between the girls and
boys indicated psychomotor development to be much faster in girls of t
hat age. Generally, data obtained by the distribution of the results f
or the two older age groups were consistent with those found in the li
terature; thus, the authors propose an early examination for the detec
tion of inborn chromatopsia to be performed in preschool children, but
not before the age of five. Ishihara's pseudoisochromatic test can be
useful in differentiating between dyschromatic and other children, bu
t it is very difficult to implement for singling out dyschromates acco
rding to the protan or deutan type.