Why do I sometimes have single/double eyelids?

When I was a kid, I always had single eyelids. Im half asian and half white, so the single eyelids were appropriate.





But ever since my teen years, it seems like they go on and off. About 3/4 the time they are single eyelid, but some days I wake up and they are double eyelids and I cant make them go single no matter what. They dont look bad, but I dont know why this happens.





Sometimes my right eyelid is double and my left is single, which looks weird so I end up having to use double eyelid tape on my left one to match my right or less it looks weird.





I used to think it meant I didnt get enough sleep, but now im thinking its random. Does anyone know about this'?

Why do I sometimes have single/double eyelids?
I can't really say since I have never heard of your sistuation but perhaps its how the texture of your eyelids feel like if its firmer or more supple. You might have a bit of excess skin which at times can be tight and give an appearance of a single lid and at other times it can supple and not as firm, so then it falls into a crise. I'm not sure, but I hope this could be of some help.