Green weakness needs to be differentially diagnosed with the following symptoms: 1. Total color weakness Also known as red, green, blue and yellow weakness. The degree of color vision impairment is lower than that of total color blindness, and there are no abnormalities in vision or other complications of total color blindness. When the object is dark and vivid, it can be distinguished; if the color is light and unsaturated, it is difficult to distinguish. Patients are also rare. 2.Partial color weakness There are red weakness (first color weakness), green weakness (second color weakness) and blue-yellow weakness (third color weakness), etc. Among them, red-green weakness is more common. Patients have poor perception of red and green, and when illumination is poor, their color discrimination ability is close to that of red-green blindness; however, when the material color is deep and sharp and illumination is good, their color discrimination ability is close to normal. 3, color blindness (weak) patients are born without the ability to correctly distinguish colors, and think that others are the same as themselves, so they can not be conscious of the disease, many color blind patients eye examination also no abnormal findings.