Hypertelorism refers to an abnormally increased distance between two bodily parts, usually referring to an increased distance between the eyes, or orbital hypertelorism.
The distance between the inner eye corners as well as the distance between the pupils is greater than normal.
Hypertelorism as seen in craniofrontonasal dysplasia.
It is a symptom in a variety of syndromes, including Edwards syndrome (trisomy 18), 1q21.1 duplication syndrome, basal cell nevus syndrome, DiGeorge syndrome and Loeys–Dietz syndrome.
Can be associated with the Apert syndrome, Autism spectrum disorder, craniofrontonasal dysplasia, Noonan syndrome, neurofibromatosis, LEOPARD syndrome, Crouzon syndrome, Wolf–Hirschhorn syndrome, Andersen–Tawil syndrome, Waardenburg syndrome, cri du chat syndrome, piebaldism, prominent inner third of the eyebrows, irises of different color, spondyloepiphyseal dysplasia, mucopolysaccharide metabolism disorder, deafness and also in hypothyroidism.
Some links between hypertelorism and attention deficit/hyperactivity disorder have been reported.
Underlying mechanism of hypertelorism is heterogeneous: early ossification of the lower wings of the sphenoid, an increased space between the orbita, due to increasing width of the ethmoid sinuses, field defects during development, a nasal capsule that fails to form, with failure of orbital migration.
When necessary craniofacial surgery to correct hypertelorism between five and eight years of age.
Surgery should be delayed until the tooth buds have grown out low enough into the maxilla, to prevent surgical damage.
Before age five the craniofacial bones are thin and fragile, making surgical correction difficult.
Two surgical options exist: The box osteotomy and the facial bipartition.
One of the techniques consists of removing the bone between the orbits.
The standard procedure is the box osteotomy.
For the correction of orbital hypertelorism, soft-tissue reconstruction is required, as well.
Bone and cartilage grafts may be necessary, and local rotation with for forehead flaps may be required
Complications from surgery: bleeding, risk of infection and CSF leaks and dural fistulas.
Rarely major eye injuries, including blindness, are seen, and visual disturbances can occur due to the eye muscle imbalance after orbital mobilization.