Sleeping on your back if there is a blurred vision, there are several possibilities: first, corneal edema, sleep on your back for too long because the eyelids are closed, the oxygen content around the cornea is relatively low, the cornea due to lack of oxygen will cause edema, edema will cause blurred vision, of course, blurred is a transient, when the eyes are opened after the oxygen content around the cornea is more adequate, corneal edema will slowly subside, the blurred vision will improve. Blurred vision will be improved. Second, because sleeping on your back compresses the retina, optic nerve vessels, causing optic nerve damage or retinal vascular occlusion, causing retinal ischemia and optic neuropathy, some people after a period of rest, due to the retinal blood supply recovery, vision will be restored. Some of them may have caused retinal and optic nerve damage, which may result in visual field defects and require symptomatic treatment and examination at a hospital.