• #1-2. Anatomical Concept of Asian Eyelid: Paradigm Shift to Evolution Eyelid Theory


    Nature exists regardless of human perception. Scientists discover a natural phenomenon, name it and set up a hypothesis to try to explain it. However, these hypotheses are sometimes based on false assumptions or about things that do not exist at all. Himly, who first adopted the term ophthalmology, was Ammon’s advisor. Ammon pioneered new concepts such as epicanthus, epiblepharon, blepharophimosis, and canthoplasty. Epicanthus and epiblepharon were discovered and defined by Ammon as key characteristics of the Asian eyes but have fallen out of favor are now used in very limited ways. Many anatomical concepts and definitions including epicanthus were established in the early 19th century. This was the time when modern ophthalmology and plastic surgery were just starting out. Therefore, we need to revisit the scientific validity of these terms against the standards of today’s medical science. At least, we need to review whether it is suitable to apply the pathological concept of epicanthus to the anatomy of an Asian face.

    To this end, we need to forget about the previously known definitions of epicanthus and first examine the Asian eyelid from a fresh perspective.


    In 1913, Bennett Bean, an American anthropologist, described the Asian eyelid as below without resorting to the concept of epicanthus.


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    “In the Mongolian, the lid disappears beneath the fold above, only the lashes project, and the inner end of the upper lid is attached below the inner end of the lower lid, which passes under it. The lids are occluded evenly in the European, and the line of occlusion is more or less straight and horizontal from the inner canthus to the outer, whereas in the Mongolian eye the upper lid overlaps the lower lid at the inner canthus, where the line of occlusion is not continuous, and the upper lid forms a bow with a dip at the nasal end and the convexity upward.”


    We can see that he does not mention the palpebral fold.


    According to Ammon’s definition, the epicanthal fold (epicanthus) refers to the fold that begins at the upper eyelid. It is regarded to originate from the medial starting point of the upper eyelid. He described this as below.


    “Ich bezeichne mit Epicanthus die angeborene Augenwinkelfalte—omitted, “


    “I named the congenital skin fold over the medial eye corner as epicanthus. Epicanthus is a congenital malformation of Metopon (Ammon’s term referring to palpebronasal skin). Epicanthus congenitus is a malformation of  the skin around the medial eye corner, and not of  the palpebral fissure. In most cases, epicanthus manifests as a congenital deformity of the skin around Metopon.”


    Image 2. Illustration of epicanthus tarsalis included in Ammon’s 1860 paper.


    -To be continued

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