Retinal hyperviscosity syndrome due to PCV: JAMA case report
A man in his 70s presented for a routine follow-up appointment. He denied any visual or systemic symptoms, and his medical history was significant for hypertension and atrial fibrillation treated with cardiac catheterization and ablation.

Medications included amlodipine besylate, 5 mg daily, and aspirin, 81 mg daily. His family and social history were unremarkable. On examination, his visual acuity was 20/20 OU. The intraocular pressure in both eyes was normal, and there was no relative afferent pupillary defect.

Extraocular motility and confrontational visual fields were also normal. On physical examination, facial plethora was evident. Retinal examination of the left eye revealed 2 blot hemorrhages and dilatation of the retinal veins. Retinal examination of the right eye also revealed dilatation of the retinal veins.

These abnormal findings were not present 1 year earlier. Fluorescein angiography revealed a prolonged arm-to-retina transit time of 22.6 seconds (normal, 10-16 seconds). Optical coherence tomography scans of the macula in both eyes were normal. In addition, an area of bruising was noted on the right shoulder in the absence of any history of trauma to the shoulder.

The complete blood cell count revealed a hemoglobin level of 21.7 g/dL (reference range, 13.5-17.0 g/dL), a hematocrit level of 66% (reference range, 40%-50%), and a red blood cell count of 8.1 × 106 /μL (reference range, 4.4-5.7 × 106 /μL). White blood cell and platelet counts were within normal limits. On referral to the division of hematology, the serum erythropoietin level was found to be 2 mU/mL (reference range, 2-29 mU/mL); the JAK2V617F mutation was identified, consistent with polycythemia vera (PV).

The patient was diagnosed with Retinal hyperviscosity syndrome secondary to polycythemia vera

Read more here: