An OCT-Based Remote Diagnosis Protocol May Help Emergency Physicians Identify CRAO

Central retinal artery occlusion (CRAO) is considered a medical emergency, and rapid diagnosis and treatment are key to maximizing positive outcomes. A retrospective review of data from a pilot program in the United States suggests that a remote diagnosis approach may facilitate triage and treatment of patients with possible CRAO in the emergency department, improving clinical outcomes.

Study Design

On May 1, 2021, an urban medical school implemented OCT nonmydriatic cameras in emergency departments associated with stroke centers at 3 affiliated hospitals with the goal of accelerating the diagnosis of acute CRAO. This retrospective study evaluated the outcomes of CRAO cases under this new protocol. During the first 18 months after institution of the program, 59 patients who presented with painless monocular vision loss were evaluated by the stroke neurology service and underwent a macular OCT on site. The images were immediately interpreted remotely by retina specialists to confirm the diagnosis of acute CRAO, allowing for subsequent treatment with intra-arterial tissue plasminogen activator (IA-tPA) for eligible patients. Treatment eligibility was determined by the stroke service and retina team based on the patient’s symptoms, visual acuity, and last known well (the last time at which the patient remembered having uncompromised vision). An in-person ophthalmology consultation was not required to make the final treatment decision.

Outcomes

Based on OCT and follow-up examination, CRAO was diagnosed in 25 patients (42%). Ten of these patients were deemed eligible for treatment, 9 of which received IA-tPA. Six treated patients (66%) had clinically significant improvement in mean visual acuity within 24 hours, all but 1 of whom maintained visual acuity gains through 1 month after treatment. The mean time to treatment was 543 minutes from last known well and 146 minutes from presentation to the stroke center.

Limitations

The treatment of acute CRAO with thrombolysis is not yet supported by randomized clinical trials, and whether thrombolysis should be administered intravenously (IV) or intra-arterially (IA) remains controversial. In addition, the authors chose to administer tPA within 12 hours, which is a longer window than the 4.5 hours for IV administration and 6 hours for IA administration recommended by most clinicians. This was also a small study with no control group.

Clinical Significance

This report demonstrates the apparent successful implementation of a remote consultation protocol using OCT in the emergency department. This is an important step forward in the rapid diagnosis of acute CRAO, opening doors to earlier therapeutic interventions and hopefully gainful vision improvement.

Financial Disclosures: Dr. Valerie Biousse discloses financial relationships with GenSight Biologics and Neurophoenix (Consultant/Advisor).