A child’s eyes may be small or large in size, which can be considered a normal physiological phenomenon, but can also be seen in pathological conditions such as congenital ptosis or blepharophimosis syndrome. 1. Physiological factors: Physiologically, there may be a slight asymmetry between the left and right eyes, which can be gradually minimized as the child grows and develops. 2. Congenital ptosis: it can be caused by the nucleus of the motor nerve or hypoplasia of the levator ani muscle, mostly hereditary, the upper eyelid can’t be lifted partially or completely, and in serious cases, the upper eyelid covers the pupil, which is manifested by different sizes of the eyes as well as visual impairment. 3. Blepharophimosis syndrome: it is genetically related and belongs to autosomal dominant inheritance, the eye can see the decrease in the horizontal diameter of the blepharophimosis, ptosis and other manifestations, and can also be accompanied by the lower eyelid ectropion, and the size of the eyes is also different at this time. If there is a big difference between the size of your child’s left and right eyes, you should go to a hospital specialist in time and follow the doctor’s instructions for standardized treatment.