Hyperviscosity-related retinopathy in Waldenstrom macroglobulinemia

Objectives: To determine the earliest retinal changes associated with Waldenstrom macroglobulinemia (WM) and to ascertain the serum IgM and serum viscosity (SV) levels at which these changes occur. Methods: Patients with WM were evaluated using indirect ophthalmoscopy with scleral depression, laser Doppler retinal blood flow measurements, and serum IgM and SV determinations. Hemodynamic findings were compared with those of a group of age-matched controls. A retinopathy severity scale was developed, and the associated IgM and SV values were related to particular morphologic changes. Results: A total of 46 patients with WM and 14 age-matched, healthy controls participated in the study. Patients exhibited far-peripheral hemorrhages and venous dilation with increasing SV and IgM values. Central retinal changes were associated with significantly higher SV values. Retinal vessel diameter increased with increasing serum IgM and SV levels. The mean IgM level of patients with the earliest retinal changes was 5442 mg/dL. The mean SV level was 3.1 cP. Conclusions: Retinal manifestations of hyperviscosity syndrome occur at lower serum IgM and SV levels than previously reported. Indirect ophthalmoscopy with scleral depression along with retinal vessel diameter measurements are able to detect the earliest hyperviscosity syndrome-related complications and should be considered in the treatment of patients with WM.