Infraorbital nerve enlargement (IONE) on magnetic resonance imaging is known to be a possible consequence of IgG4-related ophthalmic disease. However this imaging sign can also be found in other conditions causing orbital inflammation. This study aims at comparing the frequency of IONE in patients suffering from IgG4-related ophthalmic disease (IgG4-ROD) versus patients suffering from non-IgG4-related ophthalmic disease (non-IgG4-ROD)

Inclusion criteria :

• Patient aged 18 and older treated in Fondation Rothschild (tertiary ophthalmology facility, Paris, France) from January 2006 through April 2015
• Presence of a clinical orbital inflammation: mass/swelling, pain, exophthalmos, visual loss, ptosis, or diplopia.
• The presence of at least one pretherapeutic MRI confirming the inflammation of one or more orbital structures: the lacrimal gland, fat, muscles, or infraorbital nerve. The mandatory minimal MRI protocol include the following sequences: T1- and T2-weighted MRI image, in the transverse and coronal plane, and a fat-suppressed T1-weighted image in the coronal plane obtained after intravenous administration of a gadolinium chelate.
• Completion of at least one orbital biopsy with a pathologic examination and an immunohistochemical screen for IgG4.

Exclusion criteria :

• Clinical and biological signs of thyroid-associated orbitopathy
• Histologically proven lymphoma
• Pretherapeutic MRI that is insufficient for an adequate interpretation
• Absence of IgG4 testing in the pathology examination

All adult patients suffering from non-thyroid, non-lymphoma related orbital inflammation treated in Fondation Rothschild (tertiary ophtalmology facility, Paris, France) from January 2006 through April 2015.