Circles floating in front of the patient’s eyes are usually caused by vitreous clouding or posterior vitreous detachment. Vitreous clouding is an aging phenomenon, is due to with age, patients originally transparent vitreous tissue inside the gradual deposition of cloudy masses and lead to the light through the vitreous refraction, the shadow of the cloudy material will be projected on the retina, so that the patient can feel the field of vision there are black dots, lines, rings of shadows drifting. Posterior vitreous detachment is also related to aging factors, which refers to the detachment of the posterior vitreous membrane from the position of the retinal surface immediately in front of the optic disc, the vitreous body is more dense, and will form a ring-like structure, and after detachment, it will be floating in the vitreous cavity, so that the patient can feel the field of vision with a ring-shaped shadow. It is recommended that patients with dark shadows in their eyes should seek medical attention to evaluate their condition and follow the doctor’s instructions for treatment.