Question 1

Can someone be completely color blind and see only in black and white?

Accepted Answer

Yes, but it is exceedingly rare. This condition is known as Achromatopsia or complete monochromacy. It affects roughly 1 in 30,000 people globally. Individuals with this condition have no functioning cone cells in their retinas, meaning they rely entirely on rod cells. Consequently, they see the world in shades of gray and often suffer from severe sensitivity to light and reduced visual acuity.

Question 2

Why do designers still use red and green for success and error states if it is so problematic?

Accepted Answer

Red and green are deeply ingrained in human culture and psychology as universal indicators for "stop/danger" and "go/safe," largely due to the global standardization of traffic lights. Designers rely on these cultural heuristics because they instantly communicate meaning to the vast majority of users. The goal of accessibility is not to ban red and green entirely, but to ensure that these colors are always accompanied by secondary indicators, such as icons or text, so the meaning is preserved for those who cannot distinguish the hues.

Question 3

If I pass a WCAG contrast checker, do I still need to use a color blindness simulator?

Accepted Answer

Absolutely. WCAG contrast checkers only measure the luminance (lightness/darkness) difference between a foreground element and its immediate background. They do not evaluate whether two adjacent foreground elements (like two slices of a pie chart or a primary and secondary button) can be distinguished from one another. A simulator is required to ensure that color-coded information remains distinct when hue perception is mathematically compressed.

Question 4

Are women ever color blind, or is it exclusively a male condition?

Accepted Answer

Women absolutely can be color blind, though it is statistically much less common. The genes responsible for the most common types of red-green color blindness are located on the X chromosome. Because men have only one X chromosome, a single defective gene causes the condition. Women have two X chromosomes, meaning they must inherit the defective gene from both parents to express the condition. Consequently, about 8% of men have red-green color blindness, compared to roughly 0.5% of women.

Question 5

Is there a cure or medical treatment for color blindness?

Accepted Answer

Currently, there is no medical cure for genetic color vision deficiency. The condition is hardwired into the cellular structure of the retina and the genetic code. There are specialized optical lenses, such as EnChroma glasses, which use precise optical filters to enhance the contrast between specific wavelengths of light, helping some anomalous trichromats distinguish colors more easily. However, these glasses do not "cure" the condition, and they are entirely ineffective for individuals with complete dichromacy.

Question 6

How does Dark Mode impact color blindness accessibility?

Accepted Answer

Dark mode can significantly complicate color accessibility. Colors that are highly distinct and legible on a white background often lose their contrast and blend together when placed on dark gray or black backgrounds. Furthermore, the way human eyes perceive luminosity changes in low-light environments. Designers must completely re-test their color palettes using a simulator specifically in the dark mode environment, as a palette that passes accessibility checks in light mode will frequently fail in dark mode.

Color Blindness Simulator

Command Palette