Pupillary changes occur in cerebral infarction only when the infarct site happens to involve the arteriolar nerve and the arteriolar nucleus, or when there is a large cerebral infarction leading to brain herniation formation. Generally, in mild cerebral infarction, there is no change in the pupils, which are usually equally large and rounded bilaterally, with a diameter of about 2.5-3 mm and a sensitive light reflex. In the case of the articular nerve or nucleus accumbens involvement, there will be symptoms of articular nerve paralysis on the side of the lesion, with dilated pupils, loss of light reflexes, and sometimes mild corneal clouding, but this condition usually presents obvious eye movement disorders, which can be differentiated from other diseases. In the case of brain herniation formation, the pupil on one side of the patient, which often narrows first and then dilates, also often dilates to the side when dilated, and the pupil light reflex disappears completely, is related to brain herniation leading to the compression of the arteriolar nerve. In the case of occipital foramen herniation, bilateral pupil dilatation and loss of light reflex will occur at a later stage.