Characteristics Of Diabetic Capillary Nonperfusion In Extramacular White Spots On Optical Coherence Tomography Angiography

PURPOSE. To compare the characteristics of macular and extramacular white spots on wide-field swept-source optical coherence tomography angiography (SS-OCTA) and optical coherence tomography (OCT) images in diabetic retinopathy (DR).METHODS. We retrospectively reviewed 107 eyes of 64 patients with DR, of whom nominal 12 x 12 mm SS-OCTA images centered on the optic disc and ultrawide field photographs were acquired. White spots on fundus photographs corresponded to hyperreflective lesions in the superficial en-face OCT images, and the characteristics of these white spots were investigated. We compared such OCT findings with the vertical and horizontal extents of nonperfused areas (NPAs) on OCTA images.RESULTS. We observed 136 white spots and corresponding hyperreflective lesions in 49 eyes. The hyperreflective lesions in the extramacular areas had greater areas (P < 0.001) and more frequently spanned from the nerve fiber layer to the outer plexiform layer (P < 0.001), while those in the macula were superficial. All of macular hyperreflective lesions were accompanied with nerve fiber layer defects, whereas only 18 (15.4%) of 117 extramacular lesions had them (P < 0.001). Comparative studies showed that most extramacular hyperreflective lesions corresponded to the NPAs in the whole layers on OCTA images, compared to the lamellar NPAs of the superficial layer in most of the macular lesions (P < 0.001). The NPAs extended to the peripheral side more frequently in the extramacular hyperreflective lesions compared with macular lesions (P < 0.001).CONCLUSIONS. This study proposed that most of the extramacular white spots may be discriminated from macular spots with respect to diabetic NPAs on OCTA images.