There are many causes of black patches on the white eye, as follows: First, consider scleral pigment spots, manifested as purple-gray, well-defined pigment spots on the front surface of the sclera, pushing the conjunctival pigment spots do not move, especially seen in the preciliary vein penetration out of the sclera, some patients may have patchy irregular pigment spots, called scleral melanosis, which do not need to be treated. Second, it may be conjunctival pigmented nevus or malignant melanoma. The former is a benign disease, so black patches are found on the whites of the eyes with smooth surface, local elevation and clear borders, and no obvious changes will occur. The latter is a malignant disease, black plaques appear on the white of the eye, the border is not clear, cauliflower-like changes may occur, and symptoms of obvious enlargement may appear, which requires timely treatment at the hospital.