Diabetic Neuroglial Changes in the Superficial and Deep Nonperfused Areas on Optical Coherence Tomography Angiography.

Purpose: To evaluate the relationship between lamellar capillary nonperfusion on optical coherence tomography angiography (OCTA) images and neuroglial changes on structural optical coherence tomography (OCT) images in diabetic retinopathy (DR). Methods: We retrospectively reviewed 101 consecutive eyes of 69 patients with DR. OCTA and OCT images within a 3 × 3-mm square centered on the fovea were acquired simultaneously. The nonperfused areas (NPAs) in the superficial capillary layer (sNPA) (from the nerve fiber layer [NFL] to the inner plexiform layer [IPL]), the deep layer (dNPA) (corresponding mainly to the inner nuclear layer [INL]), or both layers (bNPA) were measured individually along 10 transverse lines. The corresponding lamellar neuroglial changes also were evaluated on OCT images. Results: The transverse lengths of the sNPA, dNPA, and bNPA were 2.34% (interquartile range, 0.81-5.55), 0.61% (0-1.99), and 5.96% (4.02-10.88), respectively. The length of the sNPA was correlated significantly with the lengths of no boundary between the NFL and ganglion cell layer (GCL)/IPL and the spots with inverted OCT reflectivity in the sNPA. The transverse length of the dNPA was associated with the length of cystoid spaces in the INL or Henle's fiber layer (HFL) in the dNPA. There was a significant correlation between the transverse lengths of the bNPA and no boundary between the NFL and GCL/IPL within the bNPA. Conclusions: Systematic evaluation of the OCTA-OCT association showed structural changes in the neuroglial tissues corresponding to the lamellar NPAs and suggested the feasibility of layer-by-layer evaluation of the capillary nonperfusion in DR.