Hypotelorism(Orbital or Ocular) Definition, Ultrasound, Causes, Treatment

What is Hypotelorism?

Hypotelorism, also known as stenopia, is characterized by a shorter distance between the orbits of the eye and is frequently observed in conjunction with other serious birth defects, including trigonocephaly, Meckel syndrome, microcephaly, holoprosencephaly, and chromosomal abnormalities. During the nuchal translucency anatomy scan, two tiny orbits can be spotted located in close proximity to one another.

The growth of the forebrain and midline face features are tightly connected. The most prevalent cause of hypotelorism is a problem in migration, which is typically accompanied by a defect in the development of the midline embryonic forebrain, resulting in holoprosencephaly.

A case of isolated hypotelorism is extremely rare; in eighty percent of instances, it is accompanied by holoprosencephaly.

Additionally, trisomy 13 is the most frequently identified chromosomal abnormality in hypotelorism patients. The strong correlation of trisomy 13 with hypotelorism necessitates karyotype investigation when the condition is detected. 

To find holoprosencephaly or any related abnormalities, a central nervous system-focused anatomic ultrasound scan should be carried out. The general prognosis is not good due to the high mortality rate associated with cases of trisomy 13 and the severe mental impairment associated with cases of holoprosencephaly. Both of these factors contribute to the overall poor prognosis.

Hypotelorism Definition

Hypotelorism is the abnormal shortening of the distance between any two organs. Some authors use the term interchangeably with orbital hypotelorism, which means the distance between the two eyes is too short. Therefore, when the orbital or ocular (eyes) area is affected it is referred to as orbital hypotelorism or ocular hypotelorism.

Hypotelorism Ultrasound (Sonography)

Diagnostic ultrasound is performed on the axial view of the orbits using a ventral or lateral approach. It is important to note that holoprosencephaly is a factor in the vast majority of cases of hypotelorism that are discovered in utero. As previously said, in the most severe cases of hypertelorism, the diagnosis is simple, however in the less severe ones, measuring the binocular and interocular diameters is crucial for making the correct diagnosis.

Hypotelorism Causes

It frequently results from fetal alcohol syndrome (FAS), which is brought on by excessive alcohol consumption during the first month of pregnancy. Hereditary neuralgic amyotrophy and trisomy 13, often known as Patau syndrome, are two conditions that have been linked to this condition.

In some cases, it is also connected to fragile X syndrome and the Prader–Willi syndrome. Another factor that might lead to hypotelorism is metopic synostosis, which is the early closure of the metopic suture in children's developing skulls.

Hypotelorism Treatment

In severe cases of hypotelorism, particularly those connected with genetic abnormalities, the prognosis is not good, and the mortality rate is significant.

The treatment for mild or less severe hypotelorism is a combination of surgical techniques performed in consultation with a neurosurgeon to realign the orbits into the right position.

Treatment for hypotelorism in metopic synostosis includes fronto-orbital advancement with the placement of a bone graft in the fronto-orbital region at older ages, as well as spring-assisted surgery in children younger than 6 months.