NORMAL PERIPHERAL CHOROIDAL THICKNESS MEASURED BY WIDEFIELD OPTICAL COHERENCE TOMOGRAPHY.

PURPOSE: Choroidal stasis plays an important role in the pathogenesis of many conditions and leads to choroidal thickening. However, the normal peripheral choroidal thickness (PCT) pattern remains unknown. This study investigated PCT and associated factors using ultrawidefield optical coherence tomography in healthy eyes. METHODS: This cross-sectional study included 120 healthy eyes (57 males; age, 52.0 ± 20.5 years). We used choroidal thickness maps created by ultrawidefield optical coherence tomography (viewing angle, 200°) with real-shape correction. The peripheral area was defined from 60° to 100° and further separated vertically and horizontally. The PCT and the correlations between PCT and subjects' characteristics were examined. RESULTS: The PCT were 227.1 ± 57.0 µ m, 199.6 ± 53.9 µ m, 196.6 ± 57.1 µ m, and 148.0 ± 38.2 µ m in supratemporal, infratemporal, supranasal, and infranasal areas, respectively. The thickest peripheral sector was most frequently observed in supratemporal (69.2%). The PCT negatively correlated with age in all regions ( P -values < 0.001) and axial length in supratemporal, supranasal, and infranasal areas ( P -values ≤ 0.003). The temporal PCT was thicker on the side contiguous with the posterior pole Haller's vessels ( P -values ≤ 0.020). CONCLUSION: The PCT is associated with age, axial length, and the running pattern of Haller's vessels.

Effect of photodynamic therapy on choroid of the medial area from optic disc in patients with central serous chorioretinopathy.

PURPOSE: To explore the effect of photodynamic therapy (PDT) on the choroid of medial area from optic disc and factors correlated with treatment outcomes, we evaluated choroidal changes using ultra-widefield optical coherence tomography (UWF-OCT) after PDT for central serous chorioretinopathy (CSC). METHODS: In this retrospective case-series, we included CSC patients who received a standard-dose of full-fluence PDT. UWF-OCT were examined at baseline and 3 months after treatment. We measured choroidal thickness (CT), classified into central, middle, and peripheral sectors. We examined CT changes after PDT by sectors and treatment outcome. RESULTS: Twenty-two eyes of 21 patients (20 males; mean age 58.7 ± 12.3 years) were included. CT reduction after PDT was significant in all sectors, including peripheral areas: supratemporal, 330.5 ± 90.6 µm vs. 237.0 ± 53.2 µm; infratemporal, 240.0 ± 89.4 µm vs. 209.9 ± 55.1 µm; supranasal, 237.7 ± 59.8 vs 209.3 ± 69.3 µm; infranasal, 172.6 ± 47.2 µm vs. 155.1 ± 38.2 µm (P < 0.001, for all). In patients with retinal fluid resolution, despite no apparent difference in baseline CT, there was more significant reduction after PDT in supratemporal and supranasal peripheral sectors, compared with patients without resolution: supratemporal, 41.9 ± 30.3 µm vs. -1.6 ± 22.7 µm; supranasal, 24.7 ± 15.3 µm vs. 8.5 ± 3.6 µm (P < 0.019, for both). CONCLUSIONS: Whole CT decreased after PDT, including in medial areas from optic disc. This may be associated with the treatment response of PDT for CSC.

VOLUMETRIC THREE-DIMENSIONAL OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF RETINAL NEOVASCULARIZATION IN PROLIFERATIVE DIABETIC RETINOPATHY.

PURPOSE: To evaluate structural and angiographic neovascularization in patients with proliferative diabetic retinopathy using volumetric three-dimensional optical coherence tomography angiography (OCTA). METHODS: This prospective, observational cross-sectional study included 29 eyes of 27 patients with proliferative diabetic retinopathy. The angiogenic structure, feeding vessel (epicenter), flow volume, and flow volume density of the neovasculatures were evaluated using three-dimensional OCTA imaging. The flow area and the flow area density were also measured using en face OCTA imaging. RESULTS: Sites of neovascularization were imaged successfully in 17 of the 29 eyes (58.6%). Three proposed types of neovascularization were identified on the basis of structural features seen on the three-dimensional OCTA images. Neovascularization of the adhesion type (9 of 17, 52.9%) adhered to the retinal vasculature. Those of the traction type (5 of 17, 29.4%) were partially separated from the retinal vascular plexus. Those of the mushroom type (3 of 17, 17.6%) were connected to the retinal vasculature by several epicenters. There was a significant difference between highly leaky (active) and faintly leaky (inactive) neovascularization for flow volume density, but not for flow area, flow volume, or flow area density ( P = 0.01, 0.9, 0.6, and 0.1, respectively). CONCLUSION: Volumetric three-dimensional OCTA revealed three types of neovascularization in proliferative diabetic retinopathy and may be useful for assessing neovascular activity and planning vitrectomies.

Choroidal morphologic features in central serous chorioretinopathy using ultra-widefield optical coherence tomography.

PURPOSE: To analyze the choroidal morphological changes in central serous chorioretinopathy (CSC) using ultra-widefield (UWF)-optical coherence tomography (OCT). METHODS: This single-center, case-control study included 65 CSC eyes (52 males; age, 55.6 ± 13.0 years) and 65 healthy eyes (50 males; age, 57.1 ± 17.9 years). UWF-OCT (viewing angle, 200°) with real-shape correction was used to create an automated choroidal thickness (CT) map. The CT map had three sub-areas: the central (0-30°), middle (30-60°), and peripheral areas (60-100°), and was divided by vertical and horizontal lines. Differences in the CT and the CT change rate (CTCR) from the central to peripheral areas were examined between the CSC and control groups after adjusting for subjects' demographic and clinical factors. Furthermore, we assessed the vortex veins dilation patterns (VVDP) in the macula and examined the CT and the CTCR differences between CSC patients and controls for each VVDP. RESULTS: CSC patients had greater CT than those of the controls in all sectors (CSC vs. controls, the peripheral area: supratemporal 284.4 ± 71.2 µm vs. 220.4 ± 71.2 µm, infratemporal 263.3 ± 69.2 µm vs. 195.3 ± 52.3 µm, supranasal 251.9 ± 70.3 µm vs. 189.5 ± 58.1 µm, infranasal 193.6 ± 71.2 µm vs. 146.3 ± 48.9 µm, P < 0.0001 for all sectors). The CTCR was apparently larger in CSC eyes than controls only for the upper-dominant type of VVDP (CSC patients vs. controls, supratemporal 32.1 ± 9.9% vs. 4.6 ± 23.1%, infratemporal 44.0 ± 11.2% vs. 25.6 ± 16.8%, supranasal 42.6 ± 9.8% vs. 22.2 ± 19.4%, infranasal 57.6 ± 41.2% vs. 41.2 ± 13.9%, P < 0.0001 for all sectors). CONCLUSIONS: CSC has a thicker choroid, even in the peripheral areas, and the macular choroidal thickening was more severe in the upper-dominant type of VVDP. VVDP may affect the location of excessive fluid.

Longer Interscan Times in OCT Angiography Detect Slower Capillary Flow in Diabetic Retinopathy.

Purpose: To investigate the detection of slower retinal capillary blood flow using commercial OCT angiography (OCTA) with a longer interscan time in diabetic retinopathy (DR). Design: Observational, prospective, cross-sectional study. Participants: A total of 62 eyes from 39 subjects with diabetes mellitus and 10 eyes from 9 healthy subjects. Methods: Commercial spectral domain-OCT was used to obtain 3 × 3-mm fovea-centered OCTA images of all eyes with 3 different interscan times (4.3, 5.7, and 8.6 ms). For each interscan time, OCTA imaging was performed 5 consecutive times, and a ×5 averaged image was obtained. Capillary flow density and visualization of retinal capillaries in the superficial and deep capillary plexuses (SCPs and DCPs, respectively) were compared between the 3 averaged images from the 3 different interscan times. Main Outcome Measures: Capillary flow density and visualization of foveal capillaries in 3 images with different interscan times. Results: Forty-five eyes of 34 patients were analyzed. There was no significant difference in the flow density of the SCP and DCP between the 3 images with different interscan times in all the DR stages. Some capillaries including microaneurysms that could not be observed at 4.3 ms could be observed at 5.7 or 8.6 ms. There were significantly more capillaries with difference points between the 3 images in the group with DR than in the group without DR (P < 0.01). The morphology of some microaneurysms also changed with longer interscan times. Conclusions: OCTA with longer interscan times revealed slower flow points in capillaries and more accurate visualization and morphology of microaneurysms in DR.

Deep Learning-Based Noise Reduction Improves Optical Coherence Tomography Angiography Imaging of Radial Peripapillary Capillaries in Advanced Glaucoma.

PURPOSE: We applied deep learning-based noise reduction (NR) to optical coherence tomography-angiography (OCTA) images of the radial peripapillary capillaries (RPCs) in eyes with glaucoma and investigated the usefulness of this method as an objective analysis of glaucoma. METHODS: This cross-sectional study included 118 eyes of 94 open-angle glaucoma patients (male/female = 38/56, age: 56.1 ± 10.3 years). We used OCTA (OCT-HS100, Canon) and built-in software (RX software, v. 4.5) to perform NR and calculate RPC vessel area density (VAD) and skeleton vessel length density (VLD). We also examined NR's effect on reproducibility. Finally, we assessed the vascular structure (PRCs)/function relationship at different glaucoma stages with Spearman's correlation. RESULTS: Regardless of NR, RPC parameters had excellent coefficients of variation (1.7-4.1%) in glaucoma patients and controls, and mean deviation (MD) was significantly correlated with VAD (NR: r = 0.835, p < 0.001; non-NR: r = 0.871, p < 0.001) and VLD (NR: r = 0.829, p < 0.001; non-NR: r = 0.837, p < 0.001). For mild, moderate, and advanced glaucoma, the correlation coefficients between MD and VLD were 0.366 (p = 0.028) 0.081 (p = 0.689), and 0.427 (p = 0.017) with NR and 0.405 (p = 0.014), 0.184 (p = 0.360), and 0.339 (p = 0.062) without NR, respectively. CONCLUSION: Denoised RPC images might have the potential for a closer structural/functional relationship, in which the floor effect of retinal nerve fiber layer thickness affects measurements. Deep learning-based NR promises to improve glaucoma assessment.