To the Editor: We read with special interest the article written by Touzé et al.1 The authors performed a meta-analysis of the occlusion rate and visual complications with flow-diverter stent (FDS) placed across the ophthalmic artery's origin for carotid-ophthalmic aneurysms (COA). The main findings were a high aneurysm occlusion rate (85%) and a low rate of iatrogenic visual complications, with only 3.0% of new visual symptoms, after the treatment of COA by FDS. Although this meta-analysis was well-conducted, new results published in the literature need to be discussed. It is important to mention the results of a recent work by Wu et al.2 Using computational fluid dynamics (CFD), they showed that, by analyzing hemodynamic changes from before the deployment of the flow-diverter device to afterward, the flow velocity changes in the ophthalmic artery did not present changes of relevance. Although this study includes a small sample of patients (n = 21), it proves the ability of Pipeline embolization device (PED) in ophthalmic segment aneurysm management. There are certain limitations in the study design, which may not provide a holistic picture of ophthalmic aneurysm management to the uninformed reader. For perspective, in 1990 Authur L. Day published a series of 80 cases of ophthalmic segment aneurysms (ophthalmic [41 cases] or superior hypophyseal [39 cases]) and identified 23 cases who presented with visual symptoms.3 After surgery, 17 of these cases reported an improvement with only an inferior nasal defect remaining. Overall, only 6 cases had new onset symptoms after surgery, of which 2 were not tested preoperatively, and 3 had only a nasal defect with 1 case having a diminution of vision to (20/110). In 2018, Lawton and colleagues4 reported a surgical series of 208 clipped ophthalmic aneurysms with a formal neuro-ophthalmic evaluation, in which up to 20% of aneurysms included were large or giant (>15 mm), and aneurysms presenting with a rupture or mass effect were not excluded. Vision improved in 9 (52.9%) of the 17 patients with preoperative visual deficits. Visual morbidity reported over the surgical series ranges from 0% to 28.5%, anterior clinoidectomy during surgery being the only significant factor associated with a deficit during multivariate analysis.4 Aneurysm occlusion rates in this series were 95%.4 There were only 2 studies included in the meta-analysis with a formal neuro-ophthalmologist assessment reported. Touze et al5 reported 15 cases of ophthalmic aneurysms with all cases of prior compression being excluded at the beginning and reported a 40% rate of ophthalmic complications, including 3-fugax amaurosis (18.8%) and 3 significant visual field defects (25%), and occlusion rates were 93.7%. Their study is again peculiar as the institute protocol dictated that regular coiling or balloon-assisted be used to treat ruptured aneurysms and only unruptured aneurysms with a large neck were treated by FDS. Rouchar et al6 while reporting an occlusion rate of 78.6% reported a permanent ophthalmic complication rate of 17.9%. No mention of the preoperative status of rupture or mass effect has been made with respect to ophthalmic status (acute oculomotor nerve palsy due to nerve compression by the aneurysm in 14.2%). To exclude bias in our comparison, the surgeons and interventional radiologists all mention that they were well-experienced in their studies. While FDS does offer new opportunities for the treatment of aneurysms, to extend the field of aneurysms eligible for an endovascular approach and increase long-term occlusion rates, a selective view needs to be avoided. We need to understand that in cases with a mass effect either due to the optic nerve or due to the aneurysm rupture, clipping remains a better option. We do need to acknowledge that it carries with itself a risk of thermal or vibrational injury to the optic nerve from the high-speed drill during the drilling of the anterior clinoid process, optic nerve manipulation during dissection from the aneurysm, optic pathway ischemia from the perforator occlusion or spasm, and direct optic nerve compression by the applied clip. However, as shown, experienced surgeons can deliberately reduce these complications, especially with improved dexterity.7 As such, Chiarullo et al8 published their experience in an innovative technique for decompressing the optic canal and performing an anterior clinodectomy using Kerrison rongeurs, instead of power drills.8 In intervention cases, just the arterial flow analysis may not predict ophthalmic complications after the coverage of the ophthalmic artery, as explained by the aspiration flow theory.6 In cases of laminar flow with an aspiration effect, due to a high-pressure gradient in the covered side branch, the ophthalmic artery remains patent. The aspiration flow theory has explained the same in animal studies.6 There can be cases with an asymptomatic ophthalmic artery occlusion also present because of the dual type of circulation. This is especially evident if the flow in the same pressure gradient is low as the flow diversion here will result in the thrombosis of the developing collateral network. This mechanism was first demonstrated in rabbits where lumbar arteries were covered. While in cases of unruptured aneurysms with no mass effect flow diversion may offer a treatment alternative, in cases of ruptured, large, or giant ophthalmic segment aneurysms, clipping may be a better alternative.6 In conclusion, the treatment of carotid-ophthalmic aneurysms has risks of complications in all ways of clipping and endovascular management. Future research is necessary to establish the causes of complications associated after pipeline stent deployment in the ophthalmic artery. Disclosures The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.