Patients with flying mosquito and flash sensation, usually cerebrovascular does not cause flying mosquito and flash sensation, but if the patient has hallucinations, similar symptoms may occur. Patients who suffer from floaters and flashes of light are mainly caused by vitreous clouding and posterior detachment. Posterior detachment of the vitreous body involves the retina and stimulates the retinal cells, and the patient may suffer from flashes of light. While patients with vitreous clouding can have the symptom of small black shadows flying in front of their eyes, and the small black shadows will fly in front of their eyes regardless of whether the eyeballs are rotated or not, i.e., fiducial mosquitoes. Cerebrovascular disease itself cannot cause floaters or flashes of light, but cerebrovascular disease may cause visual disturbances such as hallucinations, and patients may experience flashes of light. It is recommended that patients with significant symptoms of floaters and flashes of light should seek prompt medical attention for evaluation of their condition and treatment as prescribed by their doctor.