May Be Caused by

 Common

Apert syndrome

Craniosynostosis

Crouzon syndrome

Enucleation in childhood

Fibrous dysplasia

Hypertelorism

Leontiasis ossea

Surgery

Trauma

Treacher Collins syndrome

 Uncommon

Anophthalmos

Antral cyst

Antral neoplasm

Burkitt lymphoma

Cebocephaly

Cerebral atrophy

Craniometaphyseal dysplasia

Cyclops

Forebrain hypoplasia

Frontal encephalocele

Frontal sinus mucocele

Holoprosencephaly

Hypercalcemia

Hypotelorism

Meckel syndrome

Meningioma

Microphthalmia

Neurofibroma

Neurofibromatosis

Osteopetrosis

Osteosarcoma

Paget disease of bone

Radiation therapy

Thalassemia