Factors Defining Density of Retinal Macrophage-like Cells Displayed with Optical Coherence Tomography

Purpose: To study the factors which define the density of MLC of the inner retinal surface in healthy eyes. Methods: Healthy individuals, including candidates for LASIK surgery, and post-LASIK patients were included. MLC density was calculated using structural en face projections of OCT angiography scans. The status of the vitreoretinal interface was assessed as the distance from the inner limiting membrane to the posterior hyaloid membrane on cross-sectional scans and as the area of tight posterior vitreous adhesion on en face projections. The correlation between MLC density and various demographic and anatomical parameters, including the status of the vitreoretinal interface was calculated. Results: Fifty-four healthy individuals, 30 post-LASIK patients all without posterior vitreous detachment (PVD) as well as 20 patients with partial PVD were included. MLC density showed a statistically significant correlation with axial length, refractive error, age, subfoveal choroidal thickness, and the status of the vitreoretinal interface (p<0.05) in eyes without PVD. In multiple regression analysis the axial length was the main parameter independently correlated with MLC density (p=0.025). The status of the vitreoretinal interface had a statistically significant correlation with the axial length (p<0.001). Partial PVD was associated with almost complete loss of MLC (p<0.001). Conclusion: The status of the vitreoretinal interface is a characteristic directly defining the density of retinal MLC in healthy eyes. However, axial length appears to be a key anatomical parameter which correlates with MLC density due to its effects on the adhesion of the posterior hyaloid membrane to the retinal surface.