Key points Definition: Orbital lipomas (OL) are very rare tumors that are usually benign, accounting for less than 1% of orbital tumors. Classic clue: The patient presents with a well-circumscribed homogeneous orbital mass with low attenuation approximating orbital fat, having no calcifications or fluid-fluid level suggestive of a dermoid or teratoma. True primary OLs are as uncommon as extraorbital lipomas are common. While usually having a…

Key points Definition: Dermoids originate from totipotential germ cells. Present at birth, these differentiate abnormally, developing characteristics of mature dermal cells. Synonym: Orbital dermoids, retrobulbar orbital dermoids, or deep dermoids. Classic clue: Well-circumscribed encapsulated mass with low Hounsfield numbers, filled with high T1 signal material. Displacement of globe and ocular muscles may impair ocular motility. Compression of the optic nerve (ON) may result in visual impairment.…

Key points Definition: Optic nerve meningioma (ONM) is a rare, benign tumor arising from arachnoid cap cells in meninges covering the optic nerve (ON). Synonym: Optic nerve sheath meningioma (ONSM). Classic Clue: Appears as an enhancing mass surrounding the nonenhancing ON with “tram track” calcifications and perioptic cysts. The second most common ON tumor. Calcification is a characteristic feature on computed tomography (CT). Main differential diagnosis…

Key points Definition: Optic nerve glioma (ONG) is a type of juvenile pilocytic astrocytoma (grade 1 astrocytoma) that occurs more commonly in children and young adults. Synonym: Optic pathway glioma (OPG). Classic clue: Sausage-shaped diffuse fusiform enlargement and “kinking” of the intraorbital optic nerve (ON). More favorable prognosis compared to other astrocytoma types. Most common primary neoplasm of the ON. Bilateral ONG is pathognomonic of neurofibromatosis…

Key points Definition: Orbital cavernous hemangioma is a benign, slow-growing, vascular lesion manifesting as painless, progressive proptosis. Synonyms: Ocular cavernous hemangioma, orbital cavernous malformation, orbital cavmal. Classic clue: Well-circumscribed, enhancing intraconal mass in adult patients. Usual imaging appearance Computed tomography (CT) features: Intraconal mass. Homogeneous, well-circumscribed. Enhancement ↑↑↑↑. Magnetic resonance imaging (MRI) features: T1 isointense. T2 hyperintense. T1 + Gd enhancement. “Blooming” artifact. Most common orbital…

Key points Definition: Retinal detachment (RD) is a condition in which the inner retinal layer peels away from the middle choroidal layer of the globe permitting fluid to accumulate in what was previously only a “potential space.” It is a true medical emergency, progressing to vision loss and permanent blindness if not repaired within 24 to 72 hours. Classic clue: Middle-aged or older patient presents with…

Key points Definition: An ocular prosthesis (OP) is a device that replaces the native eye after enucleation, evisceration, or exenteration. Also known as: glass eye, artificial eye. Classic clue: The patient usually visits the radiology department for neuro computed tomography (CT) or magnetic resonance imaging for a problem totally unrelated to the OP and the device is first found by an unsuspecting resident or fellow with…

Key points Definition: Phthisis bulbi (PB) is a generic descriptive term for the ocular globe’s “end-stage” appearance after wasting away, becoming anatomically disfigured, and shrunken as a result of a range of possible prior insults. Also known as: end-stage eye, blind hypotensive eye, ocular phthisis, atrophia bulbi, atrophy eyeball, shrunken eyeball, phthisis eyeball, eyeball atrophy, and others. Classic clue: Patient commonly presents with unilateral blindness related…

Key points Definition: Ruptured globe (RG) occurs when the integrity of the eye is breeched by blunt or penetrating trauma causing full-thickness corneal or scleral breech. This is an ophthalmologic emergency. Synonym: Shattered globe. Classic clue: A man in his 30s with eye pain after having been struck by a projectile while carrying out a home-improvement project is sent by the emergency department with a request…

Key points Definition: Ocular lens displacement (OLD) refers to the malposition of the lens relative to its normal location as a result of disruption of the zonular fibers, which normally connect the lens to the ciliary body. Synonyms: Lens luxation, lens subluxation, dislocation of lens, ectopia lentis . Classic clue: The patient presents posttrauma with visual disturbance, monocular diplopia, reduced visual acuity, reduced near vision, and…

Key points Definition: Anterior chamber perforation causes loss of aqueous humor resulting in flattening or obliteration of the space between the lens and cornea. Classic clue: The patient presents with potentially penetrating eye trauma, and is found to have a small anterior chamber compared with the contralateral eye. Imaging Computed tomography features Imaging may be requested to locate intraocular or intraorbital foreign bodies. The patient may…

Key points Definition: Blowout orbital floor fractures can be repaired using titanium mesh, which gives a characteristic recognizable imaging appearance on computed tomography (CT) and magnetic resonance imaging (MRI). Classic clue: The patient presents for CT or MRI for his or her current complaint, frequently trauma to the head or face. Neither the patient nor the referring physician mentions the fact that the patient has undergone…

Key points Definition: Orbital exenteration (OE) is a radical surgical procedure involving removal of the entire orbital contents and periorbital structures. It is usually performed to treat primary orbital or periorbital malignancies that invade the orbit. Classic clue: A middle-aged man with basal cell carcinoma (BCC) near the orbit. It had been there a “long time and he thought it would go away,” but he developed…

Key points Definition: Blowout orbital floor fractures (BOFFs) result from direct trauma to the orbit transmitting force to the globe. This causes the orbital contents to “blow out” through the path of least resistance, usually the paper-thin lamina papyracea or the orbital floor. Synonym: Internal orbital fracture. Classic clue: Bowing or displacement of the inferior orbital wall in a patient with known or presumed facial trauma…

Key points Definition: Medial blowout fractures (MBOFs) result from direct trauma to the orbit transmitting most of the force to the globe. This causes the orbital contents to “blow out” through the path of least resistance, usually the paper-thin lamina papyracea or orbital floor. Classic clue: Bowing or displacement of the medial orbital wall in a patient with known or presumed facial trauma and soft tissue…