Color defects. These are terms for inherited color deficiencies: deutero refers to red-green confusion and protan refers to yellow-blue confusion. Opias have absolute confusion and anomalies have partial confusion.
Please advise what is the difference between deuteranopia and deuteranomaly, protanopia and protanomaly?
Complex. There are three colored light receptors. If one is substituted with the color of another that is termed "opia" and is the more extreme form. If the spectrum of one set is shifted but still picks up some of what it is supposed to receive that is "anomaly". These people can recognize more colors. "deutero" is red-green mix; "proto" is yellow blue mix. I call these deficiencies; not blindness.