Epicanthus is a vertical fold located between the upper and lower eyelids, partially covering the inner corner of the eye slit. In addition to the cosmetic defect, there is a narrowing of the field of vision, a feeling of “sand” or a foreign body under the eyelids, less often itching and burning. Diagnostics includes an objective examination and measurement of morphometric parameters. Patients are shown biomicroscopy, ultrasound and perimetry. Surgical correction depends on the clinical features of the pathology and is reduced to performing classical epicantoplasty, microepicantoplasty or resection of the epicanthal ligament.
Q10.3 Other malformations of the eyelid
Epicanthus (epicanthus, Mongolian fold) is a skin formation of a semilunar shape that changes the section of the eye slit. This condition is most often detected in residents of Central, Eastern and Northern Asia, in some ethnic groups its prevalence reaches 90%. Among the representatives of the Caucasian race, the frequency of occurrence is 2-5%. Physiological epicanthus accounts for 55.74% of cases, reverse internal – 24.6%, direct internal pathological – 19.62%.
Causes of epicanthus
The physiological Mongolian fold is a phenotypic feature characteristic of Asians. It is transmitted by an autosomal dominant type. The etiology of the pathological and reverse forms has not been fully studied. In such cases, scientists consider epicanthus as a stigma of dysembriogenesis. Its formation may also be due to the following factors:
- Violation of the development of the bones of the skull. In childhood, when the bones of the facial skull have not yet completed their formation, a semilunar fold appears. Normally, it is independently reduced by 10-12 years. With hypoplasia of the nasal bone, this formation does not disappear and does not decrease in size over time.
- Chromosomal abnormalities. Epicanthus is one of the clinical manifestations of the Noonan, Smith-Lemley-Opitz, Rubinstein-Tabey syndromes.
- Trauma of the eyelids. Traumatic injuries, which are accompanied by a defect in the eyelid tissues, cause difficulties at the stage of primary surgical treatment. The scarring process can cause the formation of a semilunar “flap”.
Such features of the eyelid structure are an adaptive feature for living in cold conditions. The vertical fold protects the eyes from the effects of dust, wind and bright sun, which explains the development of the physiological form. Pathological and reverse epicanthus occur due to hypertrophy of the muscle and the formation of an additional skin bend. Morphological changes are represented by a decrease in epithelial layers and, as a consequence, thinning of the epidermis.
Due to the active proliferation of the basal layers, deep acanthotic and papillomatous growths are formed. Proliferative processes in the epidermis prevail in children, at an older age there are phenomena of dyskeratosis and active growth of skin appendages. These changes are most pronounced in the pathological variant of epicanthus.
Depending on the features of the structure of the epicanthal fold, the following variants are distinguished: suprarenal, palpebral, tarsal and reverse. In the suprarenal type, the bend goes from the eyebrow to the lacrimal sac and nostril, in the palpebral type, it descends from the upper eyelid to the lower orbital edge. With the tarsal bend passes to the inner spike, with the reverse – from the lower eyelid to the medial spike. From a clinical point of view , the following forms of epicanthus are distinguished:
- Direct internal physiological. This form is usually considered as an ethnic trait, the most common among representatives of the Asian group. In combination with the structural features of the upper eyelid, it forms an oriental eye section.
- Reverse internal (palpebral syndrome). Concomitant manifestations are blepharoptosis and blepharophimosis. It occurs in people of different nationalities with chromosomal disorders. Manifests itself from birth. It does not decrease with age, requires simultaneous surgical correction along with other pathologies of the eyelids.
- Direct internal pathological. It is not accompanied by other changes of the eyelids. With age, the cosmetic defect becomes less noticeable, but it does not completely disappear. The length and width of the epicanthus is greater than in other forms.
Symptoms of epicanthus
The congenital Mongolian fold is located symmetrically on both sides. It has the form of a vertical flap covering the medial corner of the eye slit. Its width varies widely and can reach 4-5 mm. The length of the bend is determined by the form of pathology. The eyelids at the same time look somewhat thickened and protrude anteriorly. Most patients have no other clinical symptoms.
Complaints about the sensation of a foreign body occur only with excessive hypertrophy. Patients are forced to blink more often. Irritation of the orbital conjunctiva is accompanied by lacrimation and itching. The features of the course of the disease depend on the time of development of the pathological process. If epicanthus becomes noticeable from the moment of birth, its gradual, but not complete regression is possible. There is no such dynamics in the formation of adults.
Physiological epicanthus does not lead to the development of complications. The reverse and pathological forms can be accompanied by entropion. Constant irritation of the conjunctiva and cornea with eyelashes causes inflammation (conjunctivitis, keratitis). If epicanthus entails a violation of the closing of the eyelids, patients often suffer from dysfunction of the meibomian glands and dry eye syndrome. With a large size of the formation, the risk of amblyopia increases.
With an objective examination, an ophthalmologist examines and evaluates the symmetry of epicanthic folds on both sides. Using a ruler, the length and width of the eye slit are measured. Medical calipers fix the thickness and width of the formation. The doctor studies the degree of mobility of the upper eyelids. The main research methods include:
- Biomicroscopy. On the surface of the epicanthus, in contrast to the surrounding skin, changes are detected from the epithelium and dermis in the form of areas of acanthosis and papillomatosis. The severity of hyper- and parakeratosis does not depend on the clinical picture of the disease.
- Ultrasound examination. The semilunar fold is represented by a homogeneous normoechogenic formation. There are no significant differences in its structure in different forms. In elderly people, single hyperechoic inclusions may appear in the thickness.
- Perimetry. Anatomical factors normally influence the boundaries of the visual field. These include the position of the eyes in the socket, the lamination of the contours of the eyebrows, palpebral margin and bridge of the nose. With epicanthus, there is a narrowing of the visual fields from the upper temporal side.
The only method of treatment is surgical intervention (epicantoplasty). Indications for the operation are the reverse internal shape, narrowing of the visual fields, entropion, amblyopia. Often, the removal of the Mongolian fold is resorted to because of a pronounced cosmetic defect. The optimal timing of surgical treatment is from the age of 1 to 14 years, which is due to the high regenerative abilities of the skin. The following types of correction are distinguished:
- Classical epicantoplasty. Surgical intervention is performed with an oriental section of the eyes, when the epicanthus originates from the nasal side of the eye slit and passes into the thickness of the eyelid, partially covering the lacrimal muscle. During the operation, the dislocation of the semilunar fold is carried out.
- Microepicantoplasty. It is performed with a rounded shape of the formation, which completely closes the lacrimal muscle. The advantage of the technique is the absence of many angular incisions of the skin and the complete elimination of the defect. The medial angle becomes open and pointed.
- Resection of the epicanthal ligament. It is produced in the case of overlapping of the lacrimal meat by half in persons with a reverse internal type of disease. Often, surgical technique is combined with plastic surgery of the back of the nose with a silicone implant.
Prognosis and prevention
Timely intervention with epicanthus leads to the restoration of the correct position of the eyelid and the achievement of the desired cosmetic result. The operation allows you to expand the field of vision to reference values, normalize the condition of the eye surface. With minor hypoplasia of bone structures in uncomplicated cases, it is possible to independently resolve the disease with age as the bones of the facial skull grow. Specific methods of prevention have not been developed.