What is the Normal Range for Pupil Size?
The normal pupil size should be around 2 to 4 millimeters. The pupils on both sides should be equal in size and shape. If there is an abnormal pupil, it is likely related to some diseases. In addition to being related to eye nerve damage, it may also be related to brain lesions. Common causes include cerebrovascular diseases, brain tumors, and other reasons that cause abnormal pupil size.
Generally, the pupil size is 2 to 4 millimeters, and the pupils on both sides are equal in size and shape. The difference between the two pupils is generally less than 0.25 millimeters. The pupil has physiological dilation and constriction. If pathological changes occur, promptly visit the hospital for examination and symptomatic treatment. If there is no abnormal feeling, it can be ignored.
1. Pupil dilation. One-sided pupil dilation can be seen in oculomotor nerve injury, hippocampal hernia or sympathetic nerve stimulation, eye trauma, decreased vision, etc. Bilateral pupil dilation can be seen in midbrain lesions, central nervous system infectious diseases, cerebrovascular diseases, cerebral hypoxia, brain tumors, craniocerebral trauma, drug poisoning, pain, fear, hyperthyroidism, congenital abnormalities, etc.
2. Pupil constriction. One-sided pupil constriction can be seen in oculomotor nerve stimulation, cervical sympathetic nerve damage, cornea, intraocular foreign bodies, etc. Bilateral pupil constriction can be seen in infants, the elderly, syphilis, pontine lesions, cerebrovascular diseases, drug poisoning (intoxication), organophosphorus poisoning, etc.
3. Unequal pupils. One-sided oculomotor nerve palsy, skull base lesions, cerebral or midbrain lesions, cerebral sympathetic nerve palsy, etc.
