Can you really see the color right? Color weakness is also known as "abnormal trichromatic vision". Color vision defects. Being able to recognize colors but having low sensitivity is called color weakness. Patients with color weakness have poor color discrimination ability, and can only see color when the color is relatively saturated; Changes in hue can only be distinguished when there is a large difference in wavelength. Weak red (type A) and weak green (type B) are more common, and weak blue is extremely rare. Weak red has poor discrimination ability to red; Green is weak and has poor ability to distinguish green. Patients with color weakness are mostly male.