If cancer infiltrates the orbit, especially cancer from the surrounding paranasal sinuses, eye movements may be impaired, either because of extraocular muscle infiltration or involvement of the ocular motor CNs. Relative enophthalmos or associated eyelid “hang-up” on downgaze may accompany the diplopia. Occasionally, extraocular muscles may be metastatic tumor sites.
Excerpted from BCSC 2020-2021 series: Section 5 - Neuro-Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.