Unfortunate Embolization

Question: A 48 year old female undergoes corticosteroid injection of a forehead scar to improve cosmesis.  Shortly after the injection, she notices worsening vision in her right eye (ipsilateral to the injection).  She is immediately transferred to the emergency department where ophthalmologic evaluation reveals a central retinal artery occlusion.  What is the likely mechanism of vision loss in this situation?    [Answer will be posted with next week's new question]

Answer to last week's question, "Wear and Tear" (September 11, 2017)