Undiagnosed patent foramen ovale as a rare cause for branch retinal artery occlusion.

Purpose: To present the case of a man with branch retinal artery occlusion (BRAO) and concomitant patent foramen ovale (PFO), which was first diagnosed during the evaluation of BRAO.

Methods: A 35-year-old man presented with blurred vision in the left eye for 2 days. His best-corrected visual acuity (BCVA) was 6/6 in the right eye and 6/12 in the left eye. He had no ophthalmic or medical history.

Results: Ophthalmologic examination revealed a left inferior BRAO, confirmed by fluorescein angiography. The patient underwent a thorough diagnostic workup. Cardiologic examination with transesophageal echocardiography revealed a right-to-left shunt across a PFO. The patient was treated with clopidogrel and at the 15-day review, BCVA in his left eye was 6/7.5 and the retinal edema was resolved, as detected on optical coherence tomography, but relative afferent pupillary defect was persistent. The patient had developed no other embolic event at the 9-month follow-up, having undergone an operation for PFO repair.

Conclusions: Patent foramen ovale, although usually asymptomatic, should be considered among the potential causes of BRAO, especially in young patients. Prompt diagnosis and liaison with cardiologists is important to help prevent ocular or systemic embolic events and associated morbidity.