May Be Caused by

 Common

Coronal craniosynostosis

Exophthalmos

Hemangioma

Metastasis

Neurofibroma

Optic nerve glioma

Orbital pseudotumor

Retinoblastoma

Thyrotoxicosis

 Uncommon

Burkitt lymphoma

Congenital glaucoma

Congenital serous cyst

Hydatid cyst

Hydrophthalmos

Hyperthyroidism

Hypoplastic maxilla

Langerhans cell histiocytosis

Lymphoma

Neurofibromatosis

Pseudotumor

Varix of orbital vein