Etiology and Course of Ocular Ischemic Syndrome
The most common etiology of OIS is atherosclerosis; other possible causes include Eisenmenger syndrome, giant cell arteritis (GCA), and other inflammatory conditions. Most patients are older than 55 years. Typically, a 90% or greater ipsilateral obstruction is necessary to cause OIS. Approximately 20% of cases involve both eyes.
The visual prognosis for eyes with OIS is uncertain, but when rubeosis iridis is also present, visual acuity in more than 90% of cases will decline to 20/200 or worse within 1 year after diagnosis. For this reason, timely diagnosis is essential.
Approximately one-half of patients with OIS also have ischemic cardiovascular disease; one-fourth have had a previous cerebrovascular accident; and one-fifth have peripheral atherosclerotic vascular disease so severe that a previous surgical procedure was necessary. The stroke rate is higher than that of the general population, and the 5-year mortality is approximately 40%, mostly resulting from complications of cardiovascular disease.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.