The symptoms of color blindness can range from mild to severe. Many people have such mild symptoms that they are unaware that they have a color deficiency. Parents may only notice a problem with a child when he is learning his colors.
The symptoms include:
trouble seeing colors and the brightness of colors in the usual way;
inability to tell the difference between shades of the same or similar colors. This happens most with red and green, or blue and yellow.
Except in the most severe form, color blindness does not affect the sharpness of vision. The inability to see any color at all and to see everything only in shades of gray is called achromatopsia. This rare condition is often associated with:
amblyopia
nystagmus
light sensitivity, and
poor vision