Diabetic macular edema (DME) is the abnormal accumulation of fluid in the subretinal or intraretinal spaces in the macula in patients with diabetic retinopathy and leads to severely impaired central vision. Technical developments in retinal imaging systems have led to many advances in the study of DME. In particular, optical coherence tomography (OCT) can provide longitudinal and microstructural analysis of the macula. A comprehensive review was provided regarding the role of inflammation using OCT-based classification of DME and current and ongoing therapeutic approaches. In this review, we first describe the pathogenesis of DME, then discuss the classification of DME based on OCT findings and the association of different types of DME with inflammation, and finally describe current and ongoing therapeutic approaches using OCT-based classification of DME. Inflammation has an important role in the pathogenesis of DME, but its role appears to differ among the DME phenotypes, as determined by OCT. It is important to determine how the different DME subtypes respond to intravitreal injections of steroids, antivascular endothelial growth factor agents, and other drugs to improve prognosis and responsiveness to treatment.

Cystoid macular edema (CME) is the abnormal collection of intraretinal fluid in the macular region, especially in the inner nuclear and outer plexiform layers. CME leads to severe visual impairment in patients with various retinal diseases, such as diabetic retinopathy, retinal vascular occlusion, choroidal neovascularization, and uveitis. Although various retinal conditions lead to CME, a shared pathogenesis of CME is involved in these diseases. Accordingly, the pathogenesis of CME based on vasogenic mechanisms is first discussed in this review, including vascular hyperpermeability, leukostasis, and inflammation. We then describe cytotoxic mechanisms based on retinal Müller cell dysfunction. This comprehensive review will provide an understanding of the pathogenesis of CME for potential therapeutic strategies.

Aim To investigate the relationship between contrast sensitivity (CS) and retinal sensitivity (RS) assessed by microperimetry (MP) in diabetic retinopathy (DR) with clinically significant macular oedema (CSME). Methods A retrospective study was performed with 35 eyes of 35 patients with DR and CSME. Retinal thickness (RT) and MP were tested with the spectral SD-optical coherence topography/scanning laser ophthalmoscope system. Mean central RT at the fovea centre's 1 mm zone (CRT) and at the fixation centre's 1 mm zone (FCRT) was measured. RS was tested at the fixation centre, within 2° and 4° areas. CS was measured with six target sizes (6.3°, 4.0°, 2.5°, 1.6°, 1.0°, 0.64°) with a contrast glare tester. Results The mean CRT and FCRT were 344.3±136.2 and 359.9±135.5 μm, respectively. Mean log CSs (−log10) with the six target sizes ranged from 0.19 to 1.32. The mean RS at the fixation centre, within 2°, and within 4° area were 8.51±4.81 dB, 8.58±3.88 dB and 9.22±3.56 dB, respectively. RS at all tested areas were significantly correlated to log CS with all target sizes (range, r=0.366–0.755; p=0.0001–0.030). CRT and FCRT were not significantly correlated to log CS or RS. Conclusions CS and RS showed moderately significant correlations in CSME. However, neither CS nor RS was correlated with RT in patients with CSME. It could be that CS and MP are complementary to each other and are useful tools in the evaluation of functional vision.

We investigated the relationship between pachydrusen and choroidal thickness and age in eyes with polypoidal choroidal vasculopathy (PCV) and fellow eyes, compared to eyes with central serous chorioretinopathy (CSC). This retrospective study included 89 eyes with PCV and 146 eyes with CSC. The number, location, and shape of the pachydrusen and their association with choroidal thickness and age were analyzed. PCV eyes showed pachydrusen more frequently than eyes with CSC (52% vs. 20%, p < 0.001). Large solitary type and clustered type were more frequent in PCV eyes compared to CSC eyes (p = 0.003 and p = 0.001, respectively). Subfoveal choroidal thickness was associated with pachydrusen in eyes with PCV (odds ratio [OR] 1.006, 95% confidence interval [CI] 1.001–1.011, p = 0.027), while age was associated with pachydrusen in CSC eyes (OR 1.137, 95% CI, 1.073–1.205; p < 0.001). Pachydrusen were localized directly over the pachyvessel on optical coherence tomographic findings in approximately two thirds of PCV eyes and fellow eyes (62% and 67%, respectively). Risk factors for pachydrusen differ according to diseases. The presence of pachydrusen was associated with choroidal thickness in PCV, while the association with age was more prominent in CSC.

Purpose: To investigate variations in the spatial distribution of hyperreflective foci in the choroid of the macula in normal eyes. Methods: We included eyes with a normal fundus from patients who had undergone optical coherence tomography angiography, covering a 6-mm × 6-mm area centered on the fovea. The macular area was divided into nine sectors according to the modified Early Treatment of Diabetic Retinopathy Study grid. Hyperreflective choroidal foci (HCF) distribution, choriocapillaris vascular density, and choroidal stromal density were determined on en face images of the choroid in each sector. Results: We included 35 eyes from 35 participants, with a mean age of 52.7 ± 16.8 years. The mean number and area fraction of HCF at the 5-mm macular area were 35.6 ± 7.8 foci/mm² and 3.0% ± 0.7%, respectively. The number of HCF in the central circle (50.7 ± 20.9 foci/mm²) was greater than that in the inner (35.1 ± 13.0 foci/mm²) or outer rings (35.6 ± 6.5 foci/mm²) (P < 0.001, P < 0.001, respectively). The area fraction of HCF in the central circle (4.84% ± 3.36%) was greater than that in the inner (2.62% ± 1.17%; P < 0.001) or outer rings (3.12% ± 0.67%; P = 0.004). The HCF distribution did not significantly correlate with the choriocapillaris vascular density or choroidal stromal density in each sector. Conclusions: HCF were more densely distributed in the macular center than in the pericentral or peripheral macular areas. Translational Relevance: HCF measurement and spatial distribution could provide additional information for evaluating choroidal stromal characteristics.