A Rare Presentation of an Ocular Ischemic Syndrome Complicated by Neovascular Glaucoma in a Patient With Mild Carotid Artery Stenosis: A Case Report

A 72-year-old male with hypertension, dyslipidemia, ischemic heart disease, chronic kidney disease, and gout presented with painless blurred vision in the right eye, with intermittent ipsilateral headache for six months. Upon presentation, the right eye vision was 6/60 pinhole 6/36, with the presence of a relative afferent pupillary defect. An anterior segment examination revealed right eye ciliary injection and corneal edema, with anterior chamber cells and fibrin. The right eye intraocular pressure (IOP) was 52 mmHg, and gonioscopy showed an open angle with rubeosis at the angle. The right eye fundus revealed a glaucomatous optic disc with a 0.7 cup-to-disc ratio, multiple dot-blot hemorrhages over the mid-peripheral retina, and narrowed retinal arteries suggesting ocular ischemic syndrome (OIS). The left eye examination was unremarkable. The diagnosis was further confirmed by fundus fluorescein angiography, which showed a marked delay in arterio-venous transit time with a profound area of capillary fall-out at the peripheral retina. To tackle the ischemic component, a pan-retina photocoagulation laser was conducted. Topical and systemic antiglaucoma medications, topical steroids, and cycloplegics were commenced. He subsequently required a glaucoma drainage device in his right eye to control the IOP. He was investigated for the cause of OIS. Ultrasound carotid Doppler and computed tomography angiography of carotid arteries revealed bilateral internal carotid artery atherosclerotic disease with less than 50% stenosis. Double antiplatelet therapy was commenced to reduce the risk of cerebrovascular and cardiovascular events. Two months after the operation, his right eye's intraocular pressure was controlled without antiglaucoma medications. After seven months of follow-up, his right eye vision improved to 6/12 with an IOP of 10 mmHg.