Retinochoroidal and Optic Nerve Head Microstructural and Microvascular Age-Related Changes in Healthy Eyes

Abstract

Background: To investigate the retinochoroidal and optic nerve head (ONH) microstructural and microvascular age-related changes in healthy subjects by examining the ganglion cell-inner plexiform layer thickness (GC-IPLT), vessel density (VD), and their ratio. Methods: In this cross-sectional study, 203 subjects (20-69 years old) were divided into five age groups: 20-29 (G1), 30-39 (G2), 40-49 (G3), 50-59 (G4), and 60-69 (G5) (G5). Following a thorough ophthalmological examination, enhanced depth imaging optical coherence tomography (EDI-OCT) scanning was performed along with OCT angiography (OCTA) in a 6 x 6 mm(2) scanning area. Results: After adjusting for axial length the GC-IPLT varied significantly among groups, with thickness peaking in G3 (39.63 +/- 1.14 mu m) and then decreasing to the lowest in G5 (34.15 +/- 5.93 mu m) (p = 0.008). The whole, foveal, parafoveal, and perifoveal superficial and deep capillary plexus (SCP and DCP) VDs all varied significantly among groups, peaking in G2 and falling to their lowest in G5 (p < 0.05). No significant differences existed among groups regarding the GC-IPLT/whole SCP VD (p = 0.163) or GC-IPLT/whole DCP VD (p = 0.258) ratios. The foveal VDs in a 300-mu m wide region surrounding the foveal avascular zone (FAZ) (FD-300) varied significantly among groups, peaking in G1 (57.06 +/- 0.58) and dropping to its lowest in G5 (53.54 +/- 0.59) (p < 0.05). The choriocapillaris flow differed significantly among groups, peaking in G1 (20.39 +/- 0.15 mm(2)) and dropping to its lowest in G5 (19.24 +/- 0.16 mm(2)) (p < 0.001). Conclusions: The retinochoroidal microstructure and microvasculature ratios display an inverted U-shaped pattern with age, which could be linked to a considerably decreased GC-IPLT versus capillary plexus VDs with age, notably in subjects in their sixties.