The levator aponeurosis ends only at the lid plate causing monocular eyelid, while the levator aponeurosis ends at the upper eyelid furrow through the orbicularis oculi muscle in addition to the lid plate, resulting in double eyelid. Inner double eyelids are caused when the skin of the eyelid in front of the lid furrow droops down to the lower lid margin, making it look like a single eyelid, but if the eyelid is opened and closed, it can appear double. Inner double eyelid becomes single eyelid is caused by eyelid swelling, mostly seen in blepharitis, blepharitis, eyelid cellulitis, orbital cellulitis, blepharitis, lacrimal gland inflammation, lacrimal sac inflammation, acute conjunctivitis keratitis, etc. Consider inflammatory edema of the eyelid, which makes the double eyelid form disappear. Consider swelling of the eyelid caused by heart disease, kidney disease, anemia, and malnutrition. Consider eyelid swelling caused by orbital mass compression, which obstructs blood circulation or lymphatic circulation return.