In vivo characterization of retinal vascularization morphology using optical coherence tomography angiography

Purpose: To evaluate retinal vessel morphology using split-spectrum amplitude-decorrelation angiography with optical coherence tomography in healthy eyes. Methods: Fifty-two eyes of 26 healthy volunteers (age range from 35 to 48 years; mean age 41.94 years; SD: ±4.13) were evaluated by optical coherence tomography angiography in the macular region. The protocol acquisition consisted of a 216 × 216 A-scan that was repeated 5 times in the same position, in 3 × 3 mm centered into the fovea. Results: All 52 eyes showed 2 separate vascular networks in the inner retina: the superficial network, located in the nerve fiber layer and in the ganglion cell layer, and the deep network, detected in the outer plexiform layer. The superficial and deep networks showed interconnections of vertical vessels. The reference planes to observe the 2 networks were defined at 60 μm, with an inner limiting membrane reference (6 μm offset), and 30 μm, with an inner plexiform layer reference (60 μm offset), respectively. Conclusion: Optical coherence tomography angiography can separately detect the superficial vascular and the deep vascular networks. These networks are overlaid and seem to be fused when seen with standard angiographies. Furthermore, optical coherence tomography angiography technology allows for the visualization of abnormal blood column and vessel wall details.