It is not at all uncommon to note an inborn imbalance in crease shape, depth, height, and/or length as well as in the height and width of the eyelid opening (known as the "palpebral fissure" or space between the two lids that reveals the eye).
Interesting, one study comparing eyelid, eyebrow, and orbital measurements in models versus those in the average population found that small to even moderate amounts of asymmetry around the eye were more commony observed in faces perceived to be more attractive.
Natural asymmetry may be influenced by any number of anatomic variables and seems to be more common in those of Asian descent. While most patients suspect their imbalance is due to differing amounts of skin and fat in the two lids, the problem is more typically related to weak natural crease fixation rather than tissue excess or deficiency.
In most cases of objectionable asymmetry, it is advisable to operate on both eyelids simultaneously, even when one eyelid already has what if felt to be an acceptable natural crease. By applying surgery to both sides at the same time, chances are increased that the surgeon will be able to achieve a better final match. When only one eyelid undergoes surgery, it is far more difficult during the operation to judge exactly what and how much to do as well as to evaluate developing symmetry between the two sides as the operation progresses.
Less commonly, true disorders of eyelid function may be responsible for the differences between the two eyelids. For instance, in the presence of substantial ptosis affecting only one side, the deficient lid may show little or no crease formation. In such cases, ptosis surgery must be performed along with double eyelid surgery for there to be any improvement.
If crease imbalance is moderate to advanced or related to substantial anatomical differences in facial and orbital bone structure or brow position, it should be expected that at least part of the asymmetry will "pass through" any eyelid operation and be present after healing. The realistic goal in any case of surgery undertaken to address asymmetry is to achieve a more attractive match rather than near-perfection.
Some Asian eyelids show a related phenomenon in which the crease may be present but unstable and vary throughout the day.
If asymmetry is the result of previous double eyelid surgery rather than natural preexisting variability, surgical repair can prove especially challenging.
Crease reconstruction for marked natural asymmetry or unsatisfactory surgery relies on advanced techniques that are far more intricate and less predictable than those used in normal double eyelid surgery.
View the above patient before and after surgery.