Essential thrombocythemia manifesting as ophthalmic artery occlusion

Purpose: To report the first case of a patient with essential thrombocythemia (ET) who presented with unilaterally extensive choroidal ischemia coinciding with central retinal artery occlusion (CRAO).Observations: A 64-year-old man presented with a classic sign of short posterior ciliary artery (SPCA) occlusion, Amalric triangular choroidal infarction, coinciding with CRAO in the left eye. He was later diagnosed as having ET due to a massive platelet count of 1,100,000 cells/mm3 and confirmed genetic testing. The magnetic resonance angiogram subsequently revealed severe occlusions of neuro-ophthalmic circulation. Interestingly, occult choriocapillaris occlusions were detected in the right eye despite being visually asymptomatic. Conclusion and importance: Patients with ET can present with concurrent CRAO and SPCA occlusion. Identifying the causes of such events is crucial as these can precede systemic thrombocytosis or hemorrhagic complications.