Color blindness is described as:

Color blindness primarily refers to the inability or decreased ability to differentiate between certain colors, particularly red and green or blue and yellow. It stems from a deficiency in the cone cells of the retina, which are responsible for color perception. This condition typically affects how individuals identify and distinguish between colors, leading to challenges in recognizing color differences in everyday situations but does not result in seeing only black and white.

The other options describe different aspects of vision and eyesight that do not align with the definition of color blindness. For instance, seeing only black and white relates more closely to total color blindness or a rare condition known as achromatopsia rather than the more common forms of color vision deficiency. Additionally, conditions that affect night vision pertain to issues with rods in the retina rather than the cones related to color perception. The mention of a disorder affecting eye structure is unrelated to the concept of color blindness since the condition is primarily about how color is perceived rather than anatomical issues.