In vertical gaze palsy, the patient loses both casual and reflex vertical gaze due to superior gaze palsy caused by infarction of the anterior and posterior parietal regions and inferior gaze palsy caused by infarction of the medial and dorsal aspects of the red nucleus. If the posterior half of the superior colliculus is damaged, inferior vision is not possible in both eyes. What are the causes of inferior visual impairment in both eyes? 1. Actinic nerve palsy: The loss of function of the actinic nerve and its innervated tissues due to lesions in various regions is called actinic nerve palsy. When the motoneural nerve is paralyzed, the upper eyelid droops, the eye is restricted to inward, upward and downward movements and external strabismus and diplopia occur, and the pupil is dilated and the adjustment and convergence reflexes disappear. The periodic phenomenon is caused by the direct action of rhythmic impulses from the mesencephalic vegetative nerve center on the motoneurotic nerve. Congenital articular nerve palsy, which is less common, is mostly monocular and is caused by developmental abnormalities or birth injuries. Acquired motor nerve palsy. Although acquired motor nerve palsy is more common than congenital motor nerve palsy, it is less common among the three pairs of brain nerves related to eye movements. 2. Facial palsy: It is a common disease mainly characterized by motor dysfunction of facial expression muscle groups, and the general symptom is distortion of the mouth and eyes. There are many infectious lesions. It is caused by the activation of herpes zoster that is latent in the dormant state within the sensory ganglion of the facial nerve. Psychological factors are one of the important factors that trigger facial nerve palsy. Before the onset of facial nerve palsy, a significant number of patients suffer from physical fatigue, lack of sleep, mental stress and physical discomfort. It is induced by trauma, surgery, facial neuritis, and occupational diseases. Otogenic diseases, tumors, poisoning, metabolic disorders, vascular insufficiency and congenital facial nerve nucleus hypoplasia, etc.