Eyes big on one side and small on the other side is mostly related to ptosis, may be congenital genetic factors, myasthenia gravis, motor nerve palsy and other reasons, the specific treatment needs to be examined by a doctor to clarify the condition to determine. 1. Congenital genetic factors: If the eyes are big and small at the same time due to congenital causes, and if the upper eyelid can not be lifted to cover the pupil and affect the line of sight and other symptoms, most of them are considered to be congenital ptosis, which can be treated by surgical methods such as levator palpebral muscle shortening and frontalis muscle suspension surgery. 2. Myasthenia gravis: Myasthenia gravis, at the initial stage, often appear diplopia, bilateral eyelid ptosis, limited eye movement and other symptoms, later there can be inflexible eye rotation and other phenomena, this may affect the eyes on one side of the big and small, can be cholinesterase inhibitor, cyclophosphamide and other drugs to actively treat the primary disease, in order to improve the symptoms of the eyes on one side of the big and small. 3. Actinic nerve palsy: the eyes will be small on one side, there will be eyeball inward, upward, downward obstacles, and the affected side of the pupil dilated symptoms, can be oral methylcobalamin, intravenous infusion of ganglioside and other drugs to treat, and in serious cases, need to take ptosis corrective surgical treatment. In severe cases, surgery to correct ptosis is needed. If the eyes are larger on one side and smaller on the other, or if there is any discomfort such as abnormal vision, it is recommended that the patient go to the hospital for a checkup in a timely manner and follow the doctor’s instructions. All medications should be used under the guidance of a doctor, do not self-medicate.