Generality
The epicanthus is a muscle-skin fold that originates from the upper eyelid and runs over the inner corner of the eye.
Epicanthus is often seen in children with an enlarged nasal root (flat nose) and may be associated with the incomplete development of the craniofacial massif. However, when it persists in the adult, the epicantic fold must be considered as an anomaly.
If the epicanthus covers a part of the eyeball, it can simulate a squint and sometimes requires surgical correction.
Appearance and characteristics
The epicanthus is a semi-lunar plica, which tends to overlap part of the anterior surface of the eyeball, mainly at the level of the medial chant (note: less often, the epicantic fold can be located in a central or lateral position).
With respect to the eyelid opening, the epicanthus descends from the orbital region from the upper eyelid and runs until it is exhausted in the skin of the lower one, near the nasal edge.
The epicantic fold is almost always bilateral.
Epicanthus is typical of early childhood and tends to disappear with puberty.
One of the main anatomical parts of the face closely connected to the epicantial fold is the nose. In the first years of life, if the nasal root - not yet perfectly developed - is flattened and wide, the palpebral commissure may be further away from the norm and the formation of an epicanthus is more likely. Usually, these facial features tend to disappear with growth, approximately around 5-6 years of age, when the conformation of the nose is being completed.
Pseudostrabismo due to epicanthus
During childhood, epicanthus is often synonymous with pseudo-strabismus (or pseudo-esotropia). If the plica partially covers the sclera, that is the white part of the eye, in fact, it can give the impression that the ocular axes are deviated, therefore it can simulate the presence of a squint.
The false perception of ocular misalignment occurs above all during the horizontal movements of the gaze, that is when the child presenting the epicanthus looks from the side, as the distance from the inner corner of the eye seems different (in practice, it seems that one of the two eyes go more inward than the other). With growth, we tend to notice less and less this pseudo-strabismus, thanks to the completion of the formation of the root of the nose.
The epicanthus has no consequences, therefore, on the vision of the child. In any case, the eye checkups established in pediatric age are fundamental to evaluate the coordinated and synchronous movement of the eyeballs and the possible prescription of corrective lenses.
Epicanthus and Mongolian plica
The eastern eyes are characterized by the presence of eyelid folds similar to epicanthus, defined as Mongolian folds. These are to be considered as a normal somatic feature.
Mongolian plica is observed, in particular, in Asians, Native Americans (or Amerindians), Bushmen, Berbers, Inuit and, occasionally, in some European populations (such as Sami or LappĆ³ni).
Associated pathological conditions
Epicanthus can present itself as an isolated congenital alteration, but sometimes it is associated with palpebral ptosis, epiblepharon (a condition in which a horizontal skin fold crosses the upper or lower eyelid) and blepharophimosis (reduction in the width and width of the eyelid rim ).
The bilateral epicantic fold is frequently found in trisomy 21 (or Down syndrome): in the past, this disease was defined mongoloidismo due to the facial similarities shared with the Mongolian breed of Blumenbach.
Epicanthus can also occur due to prenatal alcohol exposure (fetal alcohol syndrome) and newborns affected by "Cri du Chat" syndrome due to deletion of the terminal portion of the short arm of chromosome 5 (monosomy 5p).
Other conditions in which epicantal fold can be observed include Zellweger syndrome, phenylketonuria, Turner syndrome, Williams syndrome and Noonan syndrome.
Diagnosis and treatment
In general, clinical evaluation is sufficient to diagnose epicanthus.
The presence of the plica can partially hide the eye in some extreme positions of the gaze. Therefore, when the epicanthus is excessively accentuated and disturbs sight, it can be corrected surgically.