NeuroOp Guru: Flow-diverting stents and vision — safe or risky?

In this episode of NeuroOp Guru in collaboration with Ophthalmology Times, host Andrew G. Lee, MD, is joined by Drew Carey, MD, to discuss a prospective study of the visual safety of flow-diverting stents used to treat carotid-ophthalmic aneurysms.¹

Lee is the chair of the Blanton Eye Institute at Houston Methodist Hospital and a professor of ophthalmology, neurology, and neurosurgery at the Weill Cornell Medical College. Carey is the Neil R. Miller Rising Professor of Ophthalmology in the division of neuro-ophthalmology with the Wilmer Eye Institute at Johns Hopkins University School of Medicine in Baltimore, Maryland.

A less invasive option, with little vision data

Carey explained that the traditional treatment for an intracranial aneurysm was a craniotomy, with a neurosurgeon placing a clip around the aneurysm to keep blood flow out of it and lower its risk of rupture. As vascular colleagues have become more adept at intravascular treatment, he said, they developed stents that “direct your flow past your aneurysm so you’re not getting flow into the aneurysm, reducing the pressure in the blood vessel and the risk of rupturing.”

Patients avoid a craniotomy and recover more easily, Carey said, and a less invasive approach near the ophthalmic artery is potentially beneficial. Still, “this is a newer procedure, and so there hasn’t been a lot of vision-related safety data put out there.”

What the monitoring found

The single-center study prospectively monitored patients’ vision with a systematic ophthalmologic exam, including optical coherence tomography (OCT) and OCT angiography (OCTA), before the procedure and at 15 days and 6 months afterward. Fluorescein and indocyanine green (ICG) angiography were done if anything looked abnormal. The study included 25 patients, 92% of them women, ages 36 to 76.¹

Retinal events occurred in 24% of patients, “but none of the patients suffered any functional visual impairment,” Carey said. Cotton wool spots were the most common finding, seen in 6 patients (24%), and retinal hemorrhages were seen in 3 (12.5%), with some patients showing both. OCTA showed no change, which Carey said suggested no disruption of blood flow through the carotid or ophthalmic artery to the orbit and globe. By 6 months, the authors reported, all clinical events had resolved and OCT had returned to normal.¹

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Microemboli, not occlusion

Asked by Lee what the findings represented, Carey said, “I think what we’re seeing in this picture is the sequelae of microemboli occurring.” Patients who undergo carotid revascularization can get embolic showers to the brain and eye, he said, so it is not surprising that an intravascular procedure in the ophthalmic segment of the carotid artery would release microemboli. On the fundus photograph, which showed many cotton wool spots and retinal hemorrhages, he said the material is probably platelet thrombi with some fibrin, and ICG showed choroidal perfusion with microemboli. “But the good news, these are very tiny,” he said.

Carey added that hemorrhages are not uncommon alongside small thromboembolic events. Ischemia in very small vessels typically produces cotton wool spots, he said, but some of those vessels also leak red blood cells. White-centered hemorrhages are classically seen in microemboli disease, such as Roth spots in bacterial endocarditis.

What to tell patients

No patient had a central retinal artery occlusion, a branch retinal artery occlusion, or ocular ischemic syndrome, and visual acuity and visual field testing showed no significant deficits, Carey said. Because the aneurysm is potentially life-threatening, he said, the benefits are likely to outweigh the risks.

Carey said the study’s big conclusion was that “these are safe.” For a patient asking whether to choose a flow-diverting stent or a craniotomy with clipping, “from a visual function standpoint, these are safe and a reasonable option for our patients.” For patients seen in the first 15 days after the procedure, he advised, “don’t be alarmed if you see some cotton wool spots or retinal hemorrhages. Those are to be expected.”

Reference

1. Simon C, Barrot V, Mortemousque G, et al. Retinal impact of flow-diverting stents in the treatment of carotid-ophthalmic artery aneurysms. J Neuroophthalmol. 2026;46(3):317-323. doi:10.1097/WNO.0000000000002396