LAUSR

To the Editor: We read with interest the recent article by MacGory et al regarding the pathophysiology and treatment options for central retinal artery occlusion (CRAO). We would, however, like to raise a few contentions points for discussion. We think that the authors are being overly optimistic about the visual prognosis of CRAO when they quote 17% of patients achieving functional vision, which by itself is an ambiguous term. Most patients who have suffered CRAO are left with devastating visual loss, and only those with cilioretinal artery sparing might have a better visual outcome. We also disagree with several points regarding intraarterial therapy (IAT). We do not believe an ophthalmologist needs to be present during the procedure to perform fundoscopic examination following administration of each tPA (tissue-type plasminogen activator) bolus as the retina will not immediately appear reperfused and visual acuity testing does not require the expertise of an ophthalmologist. The authors state that IA treatment is technically complex and labor intensive to deploy. We believe that when performed by a well-trained operator using proper technique, the risks of catheter-induced ophthalmic artery spasm are low. Compared to other cerebral endovascular treatments, catheterization and infusion of tPA into the ophthalmic artery is relatively straightforward. In addition, the widespread adoption of endovascular stroke therapy as the standard of care for acute ischemic stroke means that in 2020 there are 24/7 endovascular treatment stroke teams available in most major stroke centers . We would also like to comment about the authors’ conclusions on the results of the EAGLE trial (European Assessment Group for Lysis in the Eye), which found no benefit of IA treatment in 82 participants. A more recent meta-analysis reviewed 417 patients undergoing IAT of whom 236 (56.5%) demonstrated an improvement in visual acuity. While this analysis was largely comprised of retrospective studies, it does raise a question of whether a potential treatment for a devastating disease can be dismissed based on one small RCT. Of note, in the early days of endovascular treatment for stroke, the treatment, that is, now mainstream was deemed unhelpful. With regards to IAT safety, the authors quote up to 8% risk of associated stroke citing a study that showed that there were new diffusion-weighted imaging lesions in 2/25 patients undergoing IAT. This number is questionable as it is well established that diffusion-weighted imaging lesions are common after many angiographic procedures, occurring with a frequency ranging from 15% to 26%, and small areas of restriction on diffusionweighted imaging do not equate to a symptomatic stroke. The trials evaluating the use of endovascular treatment for stroke demonstrated that the risk of symptomatic intracranial hemorrhage following tPA is about 4%, and these involved much higher doses of tPA than are used in CRAO. In the recent meta-analysis cited above, there were only two cases of intracranial hemorrhage, both without any long-term neurological sequelae. We, therefore, believe that IAT for CRAO is a relatively safe procedure and concerns about safety should not preclude its consideration as a treatment option. Another recent article reviewed the role of IAT in CRAO and concluded that it should be offered to patients as soon as possible after symptom onset. To summarize, we view CRAO as an acute stroke syndrome analogous to acute ischemic stroke. In CRAO, time equals vision and these patients deserve access to the rapid multidisciplinary care and emergency treatment. We now have the 24/7 logistical capacity to treat these patients acutely with IAT which is by and large safe and can result in significant improvement in visual outcome in this devastating disease if administered early. While we definitely need more studies evaluating the use of IAT, we strongly advocate its use in treatment of acute CRAO patients.