Black dots in the eyes are impurities in the refractive interstitium, or the projection of foreign bodies on the retina, which can be divided into the following cases: First, if the black dots are fixed in front of the eyes, consider that it may be the image formed in front of the eyes by the higher density area of the cataract localization, or it may be the image formed by the pigmentation in front of the eyes due to the post-iris adhesions that occur in front of the crystal of uveitis. It is also possible that the image is formed by a foreign body embedded in the cornea, resulting in a corneal foreign body in front of the eyes. Second, if the black spot in front of the eye is floating, consider the presence of intravitreal clouding, which can be divided into physiological clouding and pathological clouding. Physiological clouding, commonly known as mosquitoes, occurs in myopic patients, long-term near eye patients and the elderly, the essence of the vitreous body is a liquefaction degeneration, so that the vitreous solute in a small amount of impurities. Pathological vitreous opacities are often associated with fundus lesions, such as diabetic retinopathy, highly myopic retinopathy, etc., which require active clinical intervention. Thirdly, there is hemorrhage in the retina of the fundus, including the macula, or exudate obscuration, forming an obscured black spot in the visual field.