Epicanthal folds are oblique or vertical folds from the upper or lower eyelids towards the medial canthus. Usually bilateral, they may involve both the upper and lower eyelids. These folds are caused by excessive development of the skin across the bridge of the nose.
- Epicanthus tarsalis: fold most prominent along upper eyelid
- Epicanthus inversus: most prominent along lower eyelid
- Epicanthus palpebralis: involves both upper and lower eyelids
- Epicanthus superciliaris: fold originates from the brow and follows down to the lacrimal sac
Epicanthus may be associated with various other conditions such as blepharophimosis, ptosis, Down syndrome, or as an isolated finding. The tarsalis variant is a normal anatomic variant of the Asian eyelid. Epicanthus inversus is associated with blepharophimosis syndrome. Children with prominent epicanthal folds may appear esotropic due to decreased scleral show nasally, resulting in pseudostrabismus.
The severity of epicanthus can be graded based on the degree of caruncle obscuration. Mild folds cover less than one third of the caruncle, moderate covers half, and severe will cover most or all of the caruncle.
Tension on the skin of the medial canthus is caused by ectopic orbicularis oculi muscle fibers and connective tissue. This leads to residual horizontal skin over the bridge of the nose and the lack of redundant vertical skin in the area causes vertical tension. Thus, correcting the fold lies in reducing the tension placed on the skin by the ectopic orbicularis fibers. Cadaver specimens with epicanthal folds have shown a connection between the upper and lower preseptal orbicularis muscle fibers. This was not evident in specimens without epicanthus.
The histologic cross section of the epicanthal fold could be divided into outer skin, a central core structure, and inner skin. The core is a combination of muscle fibers and fibrotic tissue. This fibromuscular core should be removed by the surgeon in removal or reconstruction of the epicanthal fold.
Surgical correction is only occasionally required. Frequently a mild degree of epicanthus is observed in children and is generally temporary as the folds disappear with further development of the nose and mid facial bones. Observation is generally recommended until maturation of the face if no other eyelid abnormalities are present. However, epicanthus inversus rarely resolves with growth. Surgical treatment for most isolated epicanthus is achieved linear revisions, such as a Y-V-plasty or Z-plasty. In Asian patients, epicanthus tarsalis may be eliminated with a Y-V-plasty, which may include upper lid crease formation.
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- Foster JA, et al. Basic and Clinical Science Course: Section 7. 2016-2017. American Academy of Ophthalmology.
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- Park JW, Hwan K. "Anatomy and Histology of an Epicanthal Fold." Journal of Craniofacial Surgery 27.4 (2016): 1101-103. Web. 20 Apr. 2017.