Natural double eyelids generally don't have only one fold, and there are other tiny folds beside the folds of double eyelids, while the cut double eyelids have only one trace of folds and are very smooth around.

Sometimes a cut double eyelid will have a shallow mark or dent when you close your eyes.

But now some double eyelids have been made very realistic, and it is difficult to distinguish them, such as minimally invasive double eyelids and buried double eyelids.