Association of Red Cell Distribution Width Values with Vision Potential in Retinal Vein Occlusion

Purpose: To explore a possible association of red cell distribution width (RDW), a parameter that measures variation in red blood cell size or red blood cell volume and is an index of erythrocyte heterogeneity, with vision in patients with retinal vein occlusion (RVO). Design: Cross-sectional study. Participants: Patients with either branch RVO (n = 70) or central RVO (n = 56) and gender-matched controls (n = 67) were included. Methods: All participants underwent a comprehensive ophthalmologic examination, including fundus fluorescein angiography and macular OCT (Heidelberg Spectralis; Heidelberg Engineering, Heidelberg, Germany). Exclusion criteria included RVO not confirmed by fluorescein angiography, history of malignancy, anemia, follow-up of less than 6 months, and unavailability of RDW value within 3 months of first presentation of RVO. Retinal vein occlusion patients were divided into 4 quartiles according to RDW value: quartile 1 (RDW ≤ 13.8%), quartile 2 (13.8% < RDW ≤ 14.8%), quartile 3 (14.8% < RDW ≤ 16.0%), and quartile 4 (RDW > 16.0%). Unpaired samples t tests, Pearson correlation tests, chi-square tests, analyses of variance, and multiple regression analyses were used for statistical evaluation. Main Outcome Measures: Red cell distribution width value and best-corrected visual acuity (BCVA). Results: There was no significant difference in the demographics of participants in all 3 groups with respect to age, gender, and associated systemic diseases. Red cell distribution width was significantly higher in RVO patients (14.9±1.6 μm) compared with control participants (12.5±1.4 μm; P<0.0001). There was a statistically significant correlation between RDW value and both initial BCVA (r = 0.443; P<0.0001) and final BCVA (r = 0.379; P<0.0001) in RVO patients. Both initial and final BCVA were better in RDW quartiles 1 and 2 compared with RDW quartiles 3 and 4. Conclusions: Red cell distribution width was significantly higher in RVO patients compared with control participants. Furthermore, higher RDW value was associated with lower initial and final BCVA. Red cell distribution width merits further studies related to being a potential prognostic factor for vision in RVO patients.