In polycythemia vera, which of the following retinal findings may be observed?

• A. Engorged Retinal Veins
• B. Retinal Hemorrhages
• C. Cotton-Wool Spots
• D. Normal Retina

Answer: (A)

In polycythemia vera, the blood becomes more viscous due to an increased red cell mass, which slows flow especially in the retinal venous system. This venous stasis causes the retinal veins to become dilated and tortuous—engorged retinal veins are a classic sign of hyperviscosity retinopathy. While retinal hemorrhages or cotton-wool spots can occur as consequences of slowed flow and ischemia, the most characteristic and earliest observable change is the engorged veins. A normal retina would not be expected in this setting, and recognizing venous engorgement helps indicate the need to address the elevated hematocrit to prevent progression.