FACTORS DEFINING DENSITY OF RETINAL MACROPHAGE-LIKE CELLS DISPLAYED WITH OPTICAL COHERENCE TOMOGRAPHY

To study the factors that define the density of macrophage-like cells (MLC) of the inner retinal surface in healthy eyes.

Healthy individuals, including candidates for laser in situ keratomileusis surgery, and post-laser in situ keratomileusis patients were included. Density of MLC was calculated using structural en face projections of optical coherence tomography 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.

Fifty-four healthy individuals, 30 post-laser in situ keratomileusis patients all without posterior vitreous detachment, and 20 patients with partial posterior vitreous detachment were included. Density of MLC 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 posterior vitreous detachment. 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 posterior vitreous detachment was associated with almost complete loss of MLC ( P < 0.001).

The status of the vitreoretinal interface is a characteristic directly defining the density of retinal MLC in healthy eyes. However, axial length seems to be a key anatomical parameter that correlates with MLC density because of its effects on the adhesion of the posterior hyaloid membrane to the retinal surface.