Why does one eyelid look larger than the other? (Photo)

While some asymmetry of the face and eyes is normal if you have ptosis of one eyelid surgery can be effective in improving this. Ptosis repair involves tightening of the levator muscle to eliminate eyelid drooping. If excess upper eyelid skin is hooding the eye and needs to be eliminated, an incision is made in the crease at the top of the lid and excess fat and skin are removed. The incisions are closed and sutured on the underside of the skin. I suggest making an appointment with a board certified plastic surgeon who is experienced in ptosis repair.

You have a droopy left upper eyelid (i.e. ptosis), causing the eye to look smaller.  This can be corrected by raising the eyelid (i.e. ptosis repair), and under local anesthesia.  See a specialit to learn more and best wishes.