There are two types of black dots on the eyes: First, black dots can be seen on the surface of the eye, which are considered to be caused by a physiological phenomenon. Blood vessels that travel perpendicular to the wall of the eye when they penetrate the wall of the eye manifest as black dots, which are not diseases and do not require treatment, characterized by a red blood line next to the black dot that aborts at the site of the black dot. A pigmented nevus of the conjunctiva or sclera can cause a black spot on the surface of the eye, usually present at birth, manifests as a stationary and does not progress. Second, there are black dots floating in the field of vision of the eye, also known as flying mosquitoes. Consider the vitreous turbidity caused by common in highly myopic patients and elderly patients, under normal circumstances, the vitreous cavity inside the eye is transparent, as the vitreous aging will gradually appear dotted cloudy mass, light shining on the shadow projection formed above, in the retina will be manifested as a black dot in the field of vision.