Patients may feel a circle in their vision, which may be caused by macular degeneration, posterior vitreous detachment, ocular inflammation and so on. 1. Macular degeneration: retinal vein obstruction, uveitis and other diseases can cause patients with macular disc-shaped edema, resulting in a circle in the center of the field of vision, so the patients can show the symptom that there is a circle in their eyes. 2. Posterior vitreous detachment: the vitreous body of the elderly or highly myopic patients gradually liquefies and becomes turbid, resulting in the connection between it and the retina gradually loosening. When the pressure of the eyeball increases or when it is hit by an external force, it can result in the separation of the retina from the vitreous body and the formation of a ring, i.e., the Weiss ring in front of the optic papillae, and the patients may show the symptom of having a ring in the center of the field of vision. 3. Eye inflammation: keratitis, conjunctivitis and other inflammatory diseases patients, under the stimulation of inflammation, eye secretions increase, secretions and tears can be mixed to block the pupil area, which leads to the patient to appear in the eyes to see a circle of symptoms. It is recommended that patients with abnormal vision seek medical attention to assess their condition and follow medical advice.