Object information reaches the cerebral cortex through the optic nerve and then enters the brain. If you feel dark and dizzy when you look at something, the following causes are common: 1. Blood supply problems: Insufficient blood supply to the brain is prone to darkness and dizziness, and specific problems can be found through routine monitoring of blood routine, liver and kidney function, blood lipids, blood pressure, and blood sugar. If there is anemia, the eyes will not be able to see well due to insufficient blood supply, so routine examination can be done in ophthalmology to observe whether there is anemia in the fundus of the eyes; 2. Brain problems: transient blackness and dizziness in front of the eyes need to be checked for brain tumors or epilepsy.