A 2021 study in the Journal of Psychiatry and Neuroscience compared how people with depression processed visual information compared to a control group. Researchers created computer images to test brightness and contrast. Although both groups had similar responses to brightness, those with depression had a hard time perceiving contrast. The study suggested that when people are depressed, their ability to detect differences in light and dark is affected. If people find relief from their depression, their visual processing improves.
Depression can also affect how you distinguish color, according to a 2021 pilot study in the International Journal of Psychiatry in Clinical Practice. Compared to a control group, people with depression had difficulty perceiving small color differences. The researchers suggested that depression is linked to sensory deficits. However, because this was a pilot study with a small number of participants, the researchers suggested that larger-scale studies were needed.