A fairly recent study from Korea looked at the incidence of eyelid asymmetry in a large pool of young (20-49yrs, mean 33.1yrs) Korean men (273) and women (321) and found some interesting patterns emerge. (None of the volunteers had a history of eyelid trauma or surgery.) Regarding eyelid creases (“double eyelid” vs “single eyelid”), they found that men were significantly more likely to have the single eyelid configuration than women, 66% vs 43%. One tenth of their volunteers(10.3% men and 11.5% women), possessed only one crease. Surprisingly, this unilateral crease was over twice as likely to occur in the left eyelid (7.4%) than the right (3.5%). This pattern of left sided dominance for crease formation was also reported in Japanese infants by Ishikawa. The Korean study also found that the palpebral fissure heights (vertical height between the upper and lower lids of the open eye) were significantly larger for the right eyes than the left in both men and women, and that women had significantly larger fissure heights than men. The opposite was true for horizontal fissure widths, with the left side being wider in both men and women, with men’s being significantly wider than women’s.
What was most interesting to me was that a taller vertical fissure height, narrower horizontal fissure width and a double eyelid configuration was more likely to be found naturally in Korean females than males. Although it is not discussed in this study, I believe that the data might actually explain the perceived “beautifying” result of Asian blepharoplasty surgery in Korean women. Asian blepharoplasty is not a Westernizing surgery, but more of a feminizing procedure. This also explains why some men seek the procedure to make them appear more “friendly”, and perhaps less masculine. These results also highlight the horizontal fissure width as an under appreciated feature for aesthetic eyelid reconstruction.