An uneven eyelid might be caused by using too much eye or even rubbing your eyes, either left or right side would allow as Double Line or Triple Line. In some case may occur when you are born because both eye muscles are in dissimilar parts. Their different levels are totally different based on individual cases. For the very special case can be treated by cosmetic surgery or if you are being sunken eyeball, you will probably get filler or lipofilling as treatment around that spot.
This evenly double-eyelid revision is called “repairing eyelid technique”. Only repairing eyelid, however, be inadequate for some cases in order to the saturation levels in both eyes are various. Doctors possibly use Fat Repositioning technique in some part to use fat generating your eyelids more luscious and replace the missing fat in those eye muscle disorders.
It indicates that repairing eyelid for double-eyelid is rather complexed. Hence, if you find out that you are in trouble with multiple eye problems, it would be better when you go have an appointment with doctor to get any treatment advices for a certain result.