What is the management approach for a middle-aged male patient with blurring vision, polycythemia, and normal visual acuity (VA)?

Management of Blurring Vision in Middle-Aged Male with Polycythemia and Normal Visual Acuity

This patient requires urgent evaluation for retinal vascular occlusion and immediate hematologic optimization, as polycythemia vera causes microvascular ischemia that can present with visual symptoms despite preserved visual acuity, and untreated disease carries high risk of permanent thrombotic complications. 1, 2

Immediate Diagnostic Priorities

Ophthalmologic Examination

• Perform dilated fundoscopy specifically looking for cotton wool spots, retinal hemorrhages, venous tortuosity, and papilledema, as these findings indicate retinal ischemia from hyperviscosity even when visual acuity remains normal 3, 1
• Assess for relative afferent pupillary defect, which corresponds to ischemia severity and predicts neovascularization risk 4
• Obtain optical coherence tomography (OCT) to detect subtle macular edema or inner retinal layer changes that may not be visible on clinical examination 5, 4
• Consider fluorescein angiography if fundoscopic findings are equivocal, as it can reveal markedly delayed arterial and venous filling times characteristic of polycythemia-related hyperviscosity 1

Critical Hematologic Assessment

• Measure complete blood count with attention to hematocrit, hemoglobin, white blood cell count, and platelet count, as all three cell lines may be elevated 5, 6
• Check serum erythropoietin level (typically decreased in polycythemia vera) and vitamin B12 level (typically increased) 3
• The therapeutic target hematocrit is 40-45% to reduce hyperviscosity-related complications 2

Pathophysiology Explanation

The blurred vision with normal visual acuity in this clinical scenario likely represents microvascular ischemia from blood hyperviscosity rather than frank vascular occlusion 1, 2. Polycythemia vera produces neurologic and ophthalmologic symptoms in 50-80% of patients through two mechanisms: hyperviscosity causing reduced tissue perfusion, and associated coagulopathy predisposing to both thrombosis and hemorrhage 2, 7.

Cotton wool spots without arterial or venous occlusion, as described in the literature, represent ischemic damage to the retina from greatly increased blood viscosity 1. This explains why visual acuity can remain relatively preserved (20/20 to 10/20 range) despite significant retinal pathology 1.

Immediate Treatment Algorithm

Hematologic Management (First Priority)

• Initiate urgent phlebotomy to reduce hematocrit to 40-45%, as this is the cornerstone treatment and addresses the underlying hyperviscosity 5, 2
• Phlebotomy produces immediate improvement in hyperviscosity-related symptoms including visual disturbances 1, 2
• Consider myelosuppressive therapy for high-risk patients (age >60 years or prior thrombosis history) to augment phlebotomy benefit 5

Antiplatelet Therapy

• Administer low-dose aspirin (typically 81mg daily) to alleviate microvascular symptoms including visual disturbances, as this has been shown safe and effective 5
• Excessive aspirin doses are contraindicated, but lower doses specifically address microcirculatory disturbances 5
• Aspirin has established antithrombotic efficacy and should be used unless contraindications exist (primarily conditions increasing bleeding risk) 7

Ophthalmologic Monitoring

• Schedule follow-up examination within 1-2 weeks after hematocrit reduction to document improvement in retinal findings 1
• Repeat fluorescein angiography if initially abnormal, as normalization of delayed filling times confirms therapeutic response 1

Critical Pitfalls to Avoid

Do not dismiss visual symptoms when visual acuity is normal, as this represents a dangerous misconception—isolated monocular or binocular visual loss may be the initial manifestation of polycythemia vera, and delayed treatment carries high risk of permanent complications from intravascular thrombosis 1. The presence of normal visual acuity does not preclude serious retinal ischemia 1.

Do not delay hematologic workup while pursuing extensive ophthalmologic testing, as the primary pathology is systemic hyperviscosity requiring urgent reduction of blood cell mass 1, 2. Fluorescein angiography and advanced imaging are confirmatory but should not delay phlebotomy if clinical suspicion is high.

Avoid attributing symptoms solely to refractive error, as a suddenly acquired refractive change or visual disturbance may signal systemic disease 5. This patient requires comprehensive evaluation beyond simple refraction.

Systemic Risk Assessment

• Evaluate for other thrombotic complications including cerebral venous sinus thrombosis, which can present with papilledema and visual symptoms 3
• Consider brain imaging (MRI with venography) if headache, papilledema, or other neurologic symptoms are present 3
• Screen for cardiovascular risk factors (hypertension, hyperlipidemia, diabetes) that compound thrombotic risk 4, 7

Long-Term Monitoring

After initial hematocrit reduction, patients require ongoing monitoring for disease transformation to acute myeloid leukemia or myelofibrosis, which affects long-term survival 6. Additional biomarkers including white blood cell count, platelet count, and cytokine levels may alter prognosis 6.