#2-2. Defining the Epicanthus and Two Letters from History

In Korea, epicanthus, Mongolian fold, or epicanthic fold are used interchangeably. Lee’s Medical Dictionary defines epicanthus as below.

“Medial eye corner fold, epicanthic fold, Mongolian fold. Vertical skin fold lying next to the nose which in some cases covers the medial corner of the eye. It is considered a congenital abnormality in some races but considered normal in other races.”

The definition of epicanthus or Mongolian fold differs among the medical and life science literatures. Encyclopedia of Life Science by Professor Young-hee Kang defines the Mongolian fold as following.

“A skin fold in the human upper eyelid wall that slants inferio-medially toward skin immediately below the epicanthus. Depending on the degree of development, the tear trough is partially or completely covered by this fold. It is less common in Caucasoids and more commonly seen in Mongoloid races. The Mongolian fold is present in around 70% of Koreans and Chinese, however, quite rare in Southeast Asians. Such medial eye fold structure covers a fat layer underneath and seems to have developed as part of adaptation to a cold climate.”

In the English speaking world, the epicanthus, epicanthal fold and Mongolian fold are used interchangeably, generally referring to the skin fold of upper eyelid.

The French definition of epicanthus, including that of Motais, differs from those used in other countries. This has much to do with Sichel’s in-depth examination of the epicanthus which followed Friedrich August von Ammon’s paper published in 1851. Sichel was a German born and educated French ophthalmologist. He was born in Frankfurt, Germany and studied medicine in universities of Würzburg, Tübingen and Berlin. In 1832, he opened the very first ophthalmology practice in Paris, which greatly contributed to establishment of French ophthalmology. He also trained many renowned ophthalmologists including Desmarres. In his paper, Memoire sur l'Epicanthus et sur une espece particuliere et non encore decrite de tumeur lacrymale, avec des fiynres intercalees dans le texte, Sichel accepted Ammon’s terminology of epicanthus but was critical of his etiological reasoning.

Image 2. epicanthus

Sichel cited the drawing of epicanthus from a German scholar Fritze’s book Plastiche Chirugie (1845) and explained as below.

“The roundness and the evenness of the fold of epicanthus palpebralis is somewhat exaggerated. In my personal clinical experience, I have never encountered an epicanthic fold this evenly formed.”

Sichel found that the epicanthus was more common in the Mongolian race compared to the Caucasian race. Sichel saw that the epicanthus was characteristic of the Mongolian race which settled in areas such as Northeast Asia, China, Japan, Tibet and Pacific Islands. Moreover, he also mentioned the possibility of transition between the Caucasian and Mongolian race. However, he pointed out that the epicanthus originated from the flat structure of Ossa nasi.