Sleeping with eyes half open may be due to physiological reasons, eye diseases, facial nerve paralysis and so on. 1. Physiological reasons: If the eyes are half-open at night, but the cornea is not exposed and does not cause obvious discomfort, it is generally a physiological situation. 2. Ocular diseases: If the pathological eyelid closure is incomplete due to eyelid ectropion, congenital glaucoma, orbital tumors and other ocular diseases, the eyes will be half-open during sleep. 3. Facial nerve palsy: Facial nerve palsy can lead to paralysis of the orbicularis oculi muscle of the eyelid, resulting in lower eyelid relaxation and ptosis, thus causing the eyes to be half-open during sleep. If you sleep with your eyes half open, accompanied by obvious physical discomfort, you must go to a regular hospital to find out the cause of the disease, and actively cooperate with the professional doctor’s treatment, so as to avoid delaying the condition.