Epicanthus is a disorder of structure or function in a human, animal, or plant, especially one that produces specific symptoms or that affects a specific location and is not simply a direct result of physical injury.

What is Epicanthus ?

Epicanthus or epicanthal fold is a semi-lunar fold of skin at medial canthus, with its concavity facing outward. The epicanthal fold obscures the view of the medial canthus including caruncle and plica semilunaris. This is the most common congenital lid condition. Epicanthus may be an isolated phenomenon or it may be an associated feature in patients with congenital ptosis (drooping of eyelids), Down’s syndrome or blepharophimosis (shortening of palpebral fissure both horizontally and vertically) syndrome. This condition may be unilateral or bilateral and is most prominent along the upper lid. Although, it is a normal finding in people of Asian ancestry, but is abnormal in non-Asians.

Epicanthus gives rise to the appearance of pseudostrabismus (present as pseudoesotropia). This condition does not pose any problem to the eye. However, it produces parental concern because of its resemblance to pseudoesotropia. Gentle stretch of the soft tissues of the nasal bridge reduces appearance of epicanthus at the medial canthus and reveals normal alignment of the eyes. Cover and cross-cover test reveals orthophoria (normal alignment of eyes).

Depending on the origin and configuration of free fold, there are at least four distinct types of epicanthus such as

  • Epicanthus supraciliaris.
  • Epicanthus palpebralis.
  • Epicanthus tarsalis.
  • Epicanthus inversus.

Epicanthus generally disappears by the age of puberty as the nasal bridge grows. Epicanthus inversus is usually seen in association with blepharophimosis and may be associated with relative shortage of skin in lateral periorbital area.

Epiblepharon, a related condition seen more frequently in Asians, occurs when a skin fold runs the entire length of the lower eyelid just below the eyelashes, causing them to turn inward, leading to irritation of eyes.

Epicanthus Symptoms

  • Parents usually bring the child with features such as

  • Cosmetic appearance due to epicanthal fold.
  • Suspected strabismus or squint (pseudoesotropia).
  • Obscuration of visual axis especially when eye is turned medially.
  • Associated ptosis (drooping of eyelids).

Epicanthus Causes

Epicanthus mainly results from a relative deficiency of skin in the vertical axis (as opposed to the horizontal axis) within the medial canthal area. It may occur alone or in association with other abnormalities such as

  • Telecanthus (Increased distance between two medial canthi with normal interpupillary distance).
  • Ptosis of eyelids.
  • Telecanthus and Ptosis together as in blepharophimosis syndrome.
  • Avulsion of medial canthus following trauma.
  • Iatrogenic (induced inadvertently by physician) as in abnormally high or curved dacryocystorhinostomy (DCR) incision.
  • As a part of congenital syndrome e.g. Down’s syndrome.

Epicanthus may be a normal feature in Asians.

Epicanthus Diagnosis

Diagnosis is clinical and depends on the origin and configuration of the free fold.

  • Epicanthus supraciliaris: It occurs when the free fold originates from the midpoint of the eyebrow and runs down on the side of nostril, ending over the anterior lacrimal crest. It obscures medial canthus and caruncle.
  • Epicanthus palpebralis: It is similar to epicanthus supraciliaris, except for the fact that the fold originates lower in the tarsal region of the upper eyelid, and runs down over the medial canthal region, ending at the region of the anterior lacrimal crest.
  • Epicanthus tarsalis: This occurs normally in Asians, with the epicanthal fold running along the length of the upper eyelid, obscuring the roots of the eyelashes, and ending with a curl in the medial canthus. It may not obscure the medial canthal structures and the caruncle.
  • Epicanthus inversus: It is a distinct and occurs when the fold arises in the lower eyelid at the midpupillary area and runs upward, obscuring the medial canthal angle and ending in the upper eyelid, which may or may not be affected. Instead of ellipse, the shape of the palpebral fissure is quadrangular.

Amblyopia is rare in association with epicanthus and is usually associated with other problems, such as anisometropia and astigmatism.

No spinal abnormalities are reported from patients in spite of compensatory head tilt from blepharoptosis.

Differential diagnosis

Syndromes associated with epicanthal folds such as blepharophimosis syndrome and Down’s syndrome should be looked for. Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is characterised by tetrad of blepharophimosis, ptosis, epicanthus inversus, and telecanthus.