Double eyelid fold selection is affected by whether the eye itself is protruding or it is deep set. This can be subtlely different even within the same patient. This is because the bone that surrounds the eye is asymmetric as mentioned in the prior blog. So in an eye that is protruding, you would want to set the fold slightly lower than the eye that is deep set. In a deep set eye, the double eyelid fold should be ever so slightly higher as there is more tendency for the upper eyelid skin to droop. If one looks at Asian eyelids that never had double eyelid surgery, you will notice the difference in skin hooding as one age.
In an eye with more protrusion, you need less levator muscle function to elevate the eyes. However, in an eye that is deep set, you would need more muscle function to elevate the eyes. Therefore, when there is this eye depth discrepancy, you would need to adjust the ptosis correction accordingly. That is why often patients with eyelid ptosis often present with ptosis asymmetry.
This is why double eyelid and ptosis surgery should be performed while the patient is awake. The double eyelid fold tension needs to be adjusted based on the fold height selection to create the ideal tension for the double eyelid fold creation. And the levator muscle function needs to be adjusted accordingly while evaluating the patient’s eye opening and closing. This dynamic double eyelid fold and correction of eyelid ptosis are affected by intrinsic structural anatomic variations.