November 09, 2021
Authored by Burton Wisotsky, MD
A 45 year old man noted the sudden onset of a blind spot in the vision of his right eye. The vision change was instantaneous and painless. I occurred three days ago and has not changed since. Past ocular history is significant for central serous retinopathy OD 10 years ago. Past medical history is unremarkable. He is on no medications.
On examination, VA was OD: 20/30 and OS: 20/20. IOP’s were normal. The SLE was normal. VF testing showed an inferior nasal scotoma in the right eye and was full in the left:
The differential diagnosis for sudden onset scotoma is vast, including true sudden ocular changes or new discovery of a previous ocular problem. Previous ocular problems could include retinal vascular occlusions or optic neuropathies. New onset scotoma could be due to vein occlusion, artery occlusion, retinal hemorrhage, or ischemic optic neuropathy. The dilated examination provided the answer:
The color photo and angiogram of the left eye were normal. In the right eye there was inactive macular RPE disease from a previous episode of CSR. Of note was a superior area of retinal ischemia and whitening with a visible intra-arteriolar plaque at the posterior edge. Our patient was diagnosed with an embolic branch retinal artery occlusion (BRAO).
There are two issues to consider with our patient: 1) Is there anything we can do to improve the scotoma and 2) What are the medical implications of an embolic BRAO? Regarding the vision issue, there is an experimental treatment for embolic BRAO which occasionally works. If the patients presents shortly after the occlusion, a YAG laser can be directed towards the embolus so that it can be broken up (YAG embolysis). This can in some instances break up the clot and restore blood flow. The problem is that after three days of occlusion, even if blood flow were restored, it is unlikely that significant vision will return. We elected not to do the procedure. Regarding the medical implications, there have been a number of recent studies that have suggested that BRAO or CRAO are medical emergencies in that the risk of imminent stroke is high. Some studies suggest sending the patient directly to the nearest ER for evaluation. Another way of handling this is to send the patient urgently to his medical doctor with a detailed note explaining the ocular event and likely systemic implications. Work up would include a carotid duplex study, cardiac echo, and thorough medical evaluation looking for risk factors for atherosclerosis, clotting, and systemic inflammation. In young healthy patients such as ours, it is common to find a structural cardiac defect that allowed the clot to circulate in the body and eventually make its way to the eye. The patient was sent to his PMD urgently for evaluation. He never returned for follow up so the results of the medical evaluation are unknown. From an ocular perspective, he will almost certainly have a permanent scotoma, although it may lighten a bit over the ensuing months.