Retinal Macrophage-Like Cells as a Novel Clinical Biomarker in Retinal Vein

Abstract Aim: To study the macrophage-like cells (MLC) of the inner retinal surface in eyes with retinal vein occlusions (RVO) and association of MLC with clinical characteristics of RVO.Methods: In this retrospective cross-sectional study, for treatment-naïve patients with unilateral RVO and no abnormalities of vitreoretinal interface electronic medical records and multimodal imaging data were reviewed and analyzed.To visualize MLC, structural projections of optical coherence tomography (OCT) angiography scans within a slab between two inner limiting membrane segmentation lines (with 0 and -9 µm offset) were evaluated. The density of MLC was calculated and compared between affected and fellow eye regarding different OCT and clinical characteristics of RVO.Results: Thirty-six eyes (28 branch RVO and 8 central RVO of 36 patients (21 males and 15 females, mean age 48.9 ± 9.8 years) were included. The density of MLC in affected eye was statistically significantly higher than that in fellow eye, 8.5 ± 5.5 and 4.0 ± 3.6 cells/mm2, respectively (P < 0.001). The MLC number in the affected eye correlated statistically significantly that of the fellow eye (r = 0.76, p = 0.0001) but with none of OCT and clinical characteristics of the affected eye except for the presence of subfoveal fluid. Eyes with subfoveal fluid had statistically significantly higher mean number of MLC that that in eyes without subfoveal fluid, 12.6 ± 6.3 and 6.9 ± 4.0 cells/mm2, respectively (P = 0.009).Conclusion: The number of MLC on the inner retinal surface increases in RVO eyes and may reflect activation of inflammatory reactions.