Evolution of human colour vision lights, which appear to be clear. Other colour perception issues include having trouble distinguishing yellows from reds and violet, lavender and purple from blue. In other cases, objects that reflect both red and blue light may appear to just be blue to these individuals. Deuteranopes, who are missing medium wavelength sensitive cones, are similar to protanopes in that they cannot distinguish between colours in the green-yellow-red part of the electromagnetic spectrum. However, deuteranopes do not suffer from dimming issues. For example, purple colors are not seen as being opposite to other colours in the spectrum but instead appear to be
Evolution of human colour vision with limited colour vision. This is believed to have also been influenced by life styles, including being predominantly nocturnal. There is little data indicating the advantages of UV vision in early human ancestors. Early human ultraviolet vision, or ultraviolet sensitivity, included sensitivity in the wavelength ranges between 400 and 10. These wavelengths are shorter than visible light but longer than X-rays. In some rare cases, some modern day humans can see within the UV spectrum at wavelengths close to 310. In other animals that possess UV vision such as birds, ultraviolet sensitivity can be advantageous for courtship and reproductive success.