If the lines are floating, especially in bright light can be clearly seen, but the light is not obvious in the dark, consider the possibility of physiological vitreous opacity, and ageing, myopia and other factors, the impact on vision is small, you can temporarily follow the observation, the use of drugs containing iodine for treatment will help, while the patient’s thyroid function is not The patient’s thyroid function is not abnormal. If the lines appear suddenly or have a color change, such as red slowly fade or fixed, you need to conduct a fundus examination as soon as possible, consider the possibility of pathological changes, such as vitreous hemorrhage, pre-retinal hemorrhage, etc., which is caused by retinal or choroidal hemorrhage breaking through the retinal inner boundary membrane, and need to be treated as soon as possible.