What the Eye Reveals About Vascular Disease
How to diagnose and manage common retinal vasculopathies.
Joseph W. Sowka, O.D.
Alan G. Kabat, O.D.
Ft. Lauderdale, Fla.
The eye is a singularly revealing window to the human vascular system. Nowhere else in the body can clinicians so readily view the local effects of systemic vascular disease. You can use that ability not only to diagnose retinal vascular disease, but also to detect signs of underlying pathology. This article, the second in a series of retinal “Atlases”, describes the retinal vasculopathies you will see most commonly.
This is the most common retinal vascular disease, accounting for 10 percent of new cases of blindness each year, and is the leading cause of blindness for those age 20–74. 1, 2 Yet, half of all patients with high–risk retinopathy go undiagnosed. 2.
Patients may have either juvenile–onset (type–1) diabetes, or adult–onset (type–2) diabetes. The former causes a higher incidence and greater severity of retinopathy. The retinopathy begins when the llary basement membrane thickens, leading to vessel closure. There’s a dropout of pericytes, the cells that keep normal capillaries tight. The capillary walls weaken, causing microaneurysms that then rupture, with leakage of serum proteins, lipids and blood.
Blood accumulates as dot and blot hemorrhages in the retina’s inner nuclear and outer plexiform layers, and flame–shaped hemorrhages form in the nerve fiber layer. Serum lipids aggregate as exudates, and a build–up of serous fluid causes retinal edema. This can lead to clinically significant macular edema (CSME).
Venous beading results, and further capillary closure leads to focal hypoxia and cotton wool spots. More widespread hypoxia causes a release of a vascular endothelial growth factor, stimulating neovascularization either from the disc or the capillaries of the retina or iris.
Neovascularization of the disc or elsewhere on the retina poses risk for vitreal hemorrhage and subsequent tractional retinal detachment. Iris neovascularization may cause neovascular glaucoma with secondary angle closure.