Patients often feel asymptomatic in the early stages, but as the disease progresses, they may develop mosquito flying, which means that black spots appear in front of the patient’s eyes and fly around as if they were flying mosquitoes as the eye turns. Blurred vision, double vision and other symptoms. There is usually a sudden loss of vision or blurred vision, which can occur in one eye or both eyes at the same time. In severe cases there is a risk of blindness. When fundus haemorrhage occurs in people with diabetes, they should seek prompt medical attention.