Unilateral exophthalmos exists when there is unilateral proptosis measurable by exophthalmometry. Routine roentgenographic examination of the orbit provides specific evidence of abnormality in about 50% of such cases.1 Supplementary orbital pneumotomography, angiography, and orbitography with opaque medium give even more evidence of abnormality.
Unilateral exophthalmos is most frequently caused by thyroid dysfunction; it is also found in primary orbital disease and may be secondary to extension of disease from adjacent bone, skin, sinuses, nose, nasal passages, nasopharynx, or brain. Neoplastic metastases, vascular malformation, infections or parasitic infestations, reticuloendothelioses, autoimmune diseases, fractures, or foreign bodies may also be implicated.2-4
Examination of the orbit for unilateral exophthalmos may include (1) complete routine skull examination with stereoscopic or nonstereoscopic roentgenograms including Caldwell, Waters, right and left oblique optic foramen, base, and lateral views; (2) tomography of the orbits and antra; (3) pneumotomography5 of the orbits; (4) arteriography6,7