Structural Changes in Individual Retinal Layers in Diabetic Macular Edema

Abstract

Optical coherence tomography (OCT) has enabled objective measurement of the total retinal thickness in diabetic macular edema (DME). The central retinal thickness is correlated modestly with visual impairment and changes paradoxically after treatments compared to the visual acuity. This suggests the clinical relevance of the central retinal thickness in DME and the presence of other factors that affect visual disturbance. Recent advances in spectral-domain (SD) OCT have provided better delineation of the structural changes and fine lesions in the individual retinal layers. Cystoid spaces in the inner nuclear layer and outer plexiform layer are related to quantitative and qualitative parameters in fluorescein angiography. OCT often shows vitreoretinal interface abnormalities in eyes with sponge-like retinal swelling. Serous retinal detachment is sometimes accompanied by hyperreflective foci in the subretinal fluid, which exacerbates the pathogenesis at the interface of the photoreceptors and retinal pigment epithelium. Photoreceptor damage at the fovea is thought to be represented by disruption of the external limiting membrane or the junction between the inner and outer segment lines and is correlated with visual impairment. Hyperreflective foci in the outer retinal layers on SD-OCT images, another marker of visual disturbance, are associated with foveal photoreceptor damage.

Real-World Results of Intravitreal Ranibizumab, Bevacizumab, or Triamcinolone for Diabetic Macular Edema

“…In a report of cases with both branch retinal vein occlusion and DME, serous macular detachment was shown to be a negative prognostic factor for anatomical improvement [13]. Structural analysis of individual retinal layers in the literature has concluded that eyes with foveal serous macular detachment tend to have a poorer prognosis regarding visual function [14]. Yaya et al [15] found serous macular detachment in 52.4% of 143 eyes and associated it with systemic hypertension.…”

Enhanced-Resolution Optical Coherence Tomography Imaging

“…However, we should note that the concept of ERI does not mean a complete restoration of high-resolution images without additional image information but image enhancement. We believe that the ERI method is useful as a type of display format in the analysis of fine structures in OCT images such as hyper-reflective foci [31,32,33,37], the retinal nerve fiber layer near the fovea [38,39], intricately affected photoreceptor layers [40,41], and vessels [42,43]. Further, MBP as well as IBP suffer from the drawback of noise enhancement.…”

Automatic macular edema identification and characterization using OCT images

“…In opposition, the SRD and DRT edemas typically start manifesting in the outer retina. In more severe pathological stages, the CMEs could proliferate from the inner retina to the outer retina and merge with the DRT edemas [96,97]. Based on that premises, two sub-regions are identified inside the ROI as the inner and outer retina, using the previously identified layers.…”

“…Their morphology could vary from a honeycomb shape to a petaloid-like appearance (like petals of the flowers) [96]. This edema typically emerges in the inner retina with a significant contrast with the surrounded tissue.…”