Hypertelorism: when the distance between the two orbits is too great

Definition of ocular or orbital hypertelorism

Hypertelorism corresponds to too great a distance between the two orbits. In adults the normal inter-orbital distance is between 22mm and 24mm. We speak of hypertelorism from 30 mm and major hypertelorism of more than 40 mm. “Hypertelorism is very rare since it affects approximately 1 in 100,000 people,” points out Professor Boris Laure, head of the Maxillofacial Surgery, Plastic and Burns Department at Trousseau University Hospital in Tours.

Hypertelorism and telecanthus, what is the difference between the two syndromes?

Hypertelorism should not be confused with telecanthus. Telecanthus refers to the excessive increase in the distance between the two internal angles of the eyelids. “So we can very well have an impression of hypertelorism even though the bone base is normal”says the doctor.

What are the causes of ocular hypertelorism in babies?

Hypertelorism is not a malformation but a symptom. It can be isolated or associated with malformations.

Among the hypertelorizing malformations in babies, we distinguish:

• Certain faciocraniostenoses such as Crouzon, Apert and Pfeiffer syndrome;
• The cranial clefts of the Tessier classification (cleft 0-14, cleft 1-13, cleft 2-12);
• The fronto-nasal dysplasia ;
• Craniofrontonasal dysplasia (with associated cranial malformation);
• Tumors in the fetus (teratoma, etc.) during the mother’s pregnancy;
• Anomalies of closure of the base of the skull (encephalocele).

“Hypertelorism is not necessarily hereditary”, would like to indicate the specialist. “Hypertelorism can appear sporadically. In the case of Apertou de Crouzon syndrome, it is autosomal dominant facio-craniosteosis; this means that the parent suffering from hypertelorism himself has a risk in 2 of transmitting hypertelorism to your child”.

What are the consequences of ocular hypertelorism in children?

Children and adults with hypertelorism develop an optical convergence problem leading to amblyopia. “That is to say, the brain condemns one eye and retains only one functional eye”, explains the expert.

A nasal malformation often accompanies hypertelorism (nasal bifidity, nasal cleft, etc.). This has a major aesthetic impact. Regarding the risk of mental impairment, “Without any other associated pathology, these children have completely normal mental development. would like to reassure Professor Boris Laure.

The importance of prenatal ultrasounds in making the diagnosis in the fetus?

Hypertelorism can be suspected during prenatal ultrasounds if a malformation such as syndactylie (joining two or more fingers together), a craniofacial cleft or a tumor has been detected. The sonographer can then request more precise examinations (MRI or fetal scanner).

The diagnosis of hypertelorism is primarily clinical, although mild hypertelorism may go unnoticed at birth. “Orbital growth takes place until the age of 8″, points out the Professor. “Initially you may have a small hypertelorism which can worsen around the age of 8 at the same time as orbital growth.

After diagnosis, in the first year of life, imaging such as CT or MRI will verify that there is no associated brain abnormality.

Is there a treatment for hypertelorism?

In the event of hypertelorism, children will be subject to ophthalmological monitoring. This monitoring will be carried out based on the initial ophthalmological assessment.

Hypertelorism has psychological repercussions for both parents and children. The multidisciplinary team treating hypertelorism can offer consultations with a psychologist.

Treatment by surgery is proposed in cases of moderate or significant hypertelorism but everything depends on the cause. “If you have a deformed nose, we will operate and to operate we must bring the eye sockets together.” explains Professor Boris Laure. “For example in the case of syndrome d’Apert, the surgeon advances the face in the antero-posterior direction, that is to say he advances the forehead, the orbits, the jaw of the patient (we speak of one-piece frontofacial advancement). At the same time it brings the orbits together in the vertical direction. The surgeon removes excess skin from the nose. This procedure is carried out in a single operation lasting approximately 6 hours.

Still in the case of syndromic faciocraniostenosis associated with hypertelorism, the use of internal distractors will allow, after the operation, the advancement of the facial mass using small cylinders. “These little cylinders come out through the scalp and are screwed in every day (parents or surgeons)”, explains the specialist. “It’s the same principle as for orthodontics.”

In the case of isolated hypertelorism not associated with a malformation, 2 major interventions are possible =

• The Osteotomy Box. This operation consists of cutting the orbits into a frame intracranially then removing the central part in order to bring the two parts of the face together;
• Facial bipartition. In case of wide orbital spacing and narrow maxilla, surgery consists of removing the central part of the face by cutting into a triangle. “By bringing the orbits together, the maxilla will automatically move apart. describes the surgeon. “These two interventions only manage the bony part. Other complementary surgical interventions should be planned at a distance to correct these complex malformations. In particular to reconstruct the nose (rhinoplasty) or reduce excess soft tissue on the midline.”

When to operate?

Regarding the best period to operate on the child, there are two schools. Some surgeons prefer to operate around 3-4 years of age. Others prefer to wait 8 years when orbital growth is complete and the face is more developed. “Children are also much more demanding at this age,” the specialist was able to observe.

The operation can also take place in adulthood. “The results are even better because the face is fully developed“specifies the specialist.

Please note: The humanitarian association “A smile to the face” allows the surgical treatment of children suffering from very rare craniofacial malformations (Crouzon syndrome, Pfeiffer syndrome, Apert syndrome, Hypertelorism) and living in a foreign country whose medical structures do not allow an operation.

What are congenital eye malformations?

Among the congenital malformations of the eye we find Hypotelorism (close-set eyes), Colobome (absence of eyelid, iris, retina or optic nerve), the Microphtalmie (small eyeball on one or both eyes), theAnophtalmie (absence of eyeball).