A natural appearing double eyelid fold has two types.
One is an infold double eyelid.
The second is an outfold double eyelid.
The infold is when the double eyelid fold starts below the epicanthal fold at the inner corner of the eye.
The outfold is when the double eyelid fold starts outside of the epicanthal fold at the inner corner of the eye.
However, at the outer side of the double eyelid fold, the height is the same or often slightly lower than the central aspect of the double eyelid fold. In some people, the double eyelid fold height at the outer side may go about 1mm higher than the central aspect of the double eyelid fold, but not higher than 1mm.
Often, there is some skin hooding or brow hooding where it makes the outer side of the double eyelid fold appear smaller. In these cases, upper eyelid skin should be excised or a brow or forehead lift should be performed to remove or lift the excess upper eyelid skin.