HYPERTELORISM - INTERORBITAL GROWTH, MEASUREMENTS, AND PATHOGENETIC CONSIDERATIONS

Normal pre- and post-natal changes in the interorbital distance are de scribed. Causes of illusory hypertelorism include flat nasal bridge, e picanthic folds, exotropia, widely-spaced eyebrows, narrow palpebral f issures, and dystopia canthorum. Measurements of hypertelorism may inv olve soft tissues or bone, and a number of indices have also been prop osed. Various types of measurements are evaluated and recommendations suggested. Possible pathogenetic mechanisms for hypertelorism include: early ossification of the lesser wings of the sphenoid; failure in na sal capsule development allowing the primitive brain vesicle to protru de into the space normally occupied by the capsule resulting in morpho kinetic arrest in the position of the eyes; and disturbances of the cr anial base in Apert syndrome. Associations with increased interorbital distance are also discussed: orofacial clefting, nonprotruding lipoma s of the corpus callosum, calcification of the fair cerebri, duplicati on of the crista galli, wrinkling of the nose, and tissue tags of the nose. Finally, experimental models of hypertelorism in animals are dis cussed.