Doctor, why are my new double eyelids unequal?

Several studies looking into the complications and patient dissatisfaction of double eyelid surgery found that unequal double eyelids (asymmetry of the skin creases) is one of the most common complaints (see references below). While unequal double eyelids are common immediately after double eyelid surgery, their persistence beyond 4 weeks should be regarded as permanent. Patients who have significant unequal double eyelids (more than 1 mm different) often seek help to address the imbalance. 

This 38 year-old underwent double eyelid surgery in a beauty saloon using the suture technique. The procedure was performed by a "doctor" from China of dubious qualification. Post-operatively, she noticed significant unequal double eyelids. Despite repeated reassurance from the beauty saloon owner, the asymmetry remained 8-week post-operative. Unfortunately, the surgeon had since gone and could not be contacted.

The three possible causes of this deformity noted were:

a.       The difference in measuring and marking the skin for suturing or incision

b.      Different skin tension while doing supratarsal fixation and

c.        Differing widths of skin excision in upper eyelids.

References:

1. Strategies for a successful corrective Asian blepharoplasty after previously failed revisions. Chen SH, Mardini S, Chen HC, Chen LM, Cheng MH, Chen YR, Wei FC, Weng CJ. Plast Reconstr Surg. 2004 Oct;114(5):1270-7; discussion 1278-9.
2. Complications of Oriental blepharoplasty. Weng CJ, Noordhoff MS. Plast Reconstr Surg. 1989 Apr;83(4):622-8.
3. Unfavorable results in Oriental blepharoplasty. Hin LC. Ann Plast Surg. 1985 Jun;14(6):523-34. No abstract available.