Dr. Bong-shik Kwon of Teuim Plastic Surgery is a blepharoplasty specialist who has researched blepharoplasty for many years. He has suggested a new paradigm for understanding the concept of epicanthus, a common anatomical structure found in Asians, from an evolutionary biological perspective. In this article, Dr. Kwon discusses the anatomy of the medial eye area as well as surgical techniques of blepharoplasty in the hope to clarify the misunderstanding caused by the epicanthus theory. 

 

Many studies examined the anatomical differences between the Asian and Caucasian eye structures. Most books and papers on Asian blepharoplasty point out that the gross anatomical differences between the Asian and Caucasian eyes are the lack of palpebral fold and presence of epicanthus. These are considered two axioms in the field of Asian eye anatomy.

Epicanthus is currently defined as “a vertical fold of skin over the angle of the inner canthus of the eye” (Mosby's Medical Dictionary). It is also explained rather vaguely as “anatomical characteristic in Asian ethnicity.” The book Plastic Surgery (Neligan. 2013) explains that the epicanthus, including a milder form, is present in most Asians. Despite many variations of the term, it is commonly referred to as “epicanthus” in Korea. The textbook explains that Asians have a single eyelid, palpebral folds of various sizes and various forms of epicanthus. In gross anatomy, the Caucasian medial eye is exposed in the shape of a water drop. On the other hand, the Asian medial eye takes various forms and is often covered with drooping of soft tissue beyond the distal end of upper eyelid. In Asians, the epicanthus most often refers to this drooping soft tissue draped over the medial canthus.

Among many anatomical differences that separate the Caucasian and Asian eye structures, the epicanthus was a bit of a medical mystery as it was yet to be clearly defined. Since F. A. von Ammon first described epicanthus, it has been analyzed from a pathological perspective as a congenital malformation.

 

Image 1. Ammon’s paper, Der Epicanthus und das Epiblepharon , zwei Bildungsfehler der menschlichen Gesichtshaut (Epicanthus  and Epiblepharon; Two types of human facial deformities)

 

Ammon1831 – developmental arrest, skin abundance

Sichel 1851 –  transition of the Caucasian race into the Mongolian

                low and broad nasoethmoidal bone

Metschnikoff 1874 – developmental arrest, the most primitive type

Duke-Elder-developmental arrest

Lee 2000 – developmental error

Hwang 2016 – developmental error

 

HELIOSⅡ/LOTUSⅡ/HYPERION – Manufacturer: LASEROPTEK(www.laseroptek.com)

 

There are many other opinions on this topic that fell to the wayside throughout history. Some of these warrant our attention. Before we examine the embryological origins or structure of the elusive concept of epicanthus, we need to first review the validity of the long-accepted pathological definition of epicanthus and how the definition has evolved over time. We also need to reexamine the process and scientific evidence behind the epicanthus hypothesis.

 

-To be continued