Black smudges in the eyes are usually caused by physiologic vitreous clouding or vitreous blood accumulation. The occurrence of physiological vitreous clouding is generally due to aging factors, the incidence of highly myopic patients is higher than ordinary people, is due to the originally transparent vitreous tissue inside the formation of cloudy cell metabolism products, thus affecting the refraction of light, casting shadows on the patient’s retina, resulting in the patient’s field of vision has a black shadow like smoke. If the patient has vitreous blood, the blood cells will also block the refraction of light when they disperse, resulting in a smoky black shadow in the patient’s field of vision. It is recommended that patients with obvious dark shadows in front of their eyes should seek medical attention in a timely manner to evaluate their condition and follow the doctor’s instructions for treatment.