Structural OCT Research Articles

Imaging Features Associated with Progression to Geographic Atrophy in Age-Related Macular Degeneration: Classification of Atrophy Meeting Report 5

To provide an image-based description of retinal features associated with risk for development of geographic atrophy (GA) in eyes with age-related macular degeneration (AMD), as visualized with multimodal imaging anchored by structural OCT. Consensus meeting. International group that included those with expertise in imaging and AMD basic science and histology, and those with Reading Center experience in AMD clinical trials. As part of the Classification of Atrophy Meeting program, an international group of experts analyzed and discussed retinal multimodal imaging features in eyes with AMD associated with GA, risk of progression to GA, or both. Attendees undertook premeeting grading exercises that were reviewed during the meeting sessions. Meeting presentations illustrated established and investigational multimodal imaging features and associated histologic features. Each of these different features were then discussed openly by the entire group to arrive at consensus definitions. These definitions were applied to 40 additional images that were graded independently by attendees to refine the consensus definitions and descriptions further. Consensus was reached on images with descriptors for 12 features. These features included components of outer retinal atrophy (e.g., ellipsoid zone disruption), components of complete retinal pigment epithelium (RPE) and outer retinal atrophy (e.g., RPE perturbation with associated hypotransmission or hypertransmission), features frequently seen in eyes with atrophy (e.g., refractile drusen), and features conferring risk for atrophy development (e.g., hyperreflective foci, drusen, and subretinal drusenoid deposits). An international consensus on terms and descriptions was reached on multimodal imaging features associated GA and with risk for GA progression in eyes with AMD. We believe this information will be useful to clinicians who manage patients with AMD, researchers who study AMD disease interventions and pathogenesis, and those who design clinical trials for therapies targeting earlier AMD stages than GA expansion.

Progressive development of large choroidal excavation in neovascular age-related macular degeneration.

Focal choroidal excavation (CE) is an unusual concavity in the choroid without posterior staphyloma or scleral ectasia and with pathogenesis is still unknown. In this article we present a case of de novo progressive focal choroidal excavation associated with exudative age-related macular degeneration (AMD). This study was designed as a descriptive case report based on clinical and imaging data collected during patient's observation and follow-ups. A 67-year-old man with systemic hypertension and hypercholesterolemia, with a previous diagnosis of bilateral AMD complicated by already treated macular neovascularization, underwent our attention to perform follow-up visits. Over the 5-year follow-up, the left eye remained stable, requiring no further treatments and disclosing a BCVA of 0.0 LogMAR. On the contrary, the right eye showed several exudation recurrences, requiring further anti-VEGF injections. Structural OCT detected the progressive development of a focal CE, which gradually enlarged converting into a large CE. Structural OCT examinations reported even growing defects of the Bruch's membrane. Despite the evident progression of the CE, BCVA disclosed stable values over the 5-years follow-up (1.0 LogMAR), with a worsening of metamorphopsia. Large CE may be a complication of neovascular AMD. Bruch's membrane abnormalities, including thickness and reflectivity changes, detectable on structural OCT, can be considered early biomarkers of potentially developing CE.

Extralesional microvascular and structural macular abnormalities in cytomegalovirus retinitis

To evaluate extralesional microvascular and structural changes of the macula using optical coherence tomography angiography (OCTA) and structural OCT in cytomegalovirus retinitis (CMVR). An observational study of CMVR patients were performed. Complete ophthalmic examination, serial color fundus photography, structural OCT and OCTA were performed at baseline and follow-up visits for up to 12 months. The structural OCT was analyzed to evaluate macular areas within, bordering and beyond the CMVR lesions. Extralesional retinal capillary plexus of the macula were evaluated by OCT angiography and compared with the unaffected fellow eyes. Thirteen eyes from 13 patients were enrolled. At baseline, macular areas without CMVR lesions showed decreased vessel density (VD) of both the superficial (P = 0.0002) and deep (P < 0.0001) retinal capillary plexus in eyes with CMVR as compared with the corresponding macular areas of the unaffected fellow eyes. The decrease of VD persisted through the follow-up period for up to 12 months after adjusting for degree of vitreous haze. Structural macular OCT characteristics at the borders and beyond the lesions included intraretinal hyperreflective dots, cystoid macular edema, subretinal fluid and selective ellipsoid zone (EZ) loss. The selective EZ loss found in 6 of 12 eyes showed recovery in 4 eyes after receiving anti-viral treatment. In CMVR eyes, there were microvascular and microstructural abnormalities in the macular area without clinically visible CMVR lesions. Our results provided interesting insights into CMV infection of the retina.

Structural En Face OCT Angiography Image of Avulsed Retinal Vessels and Vitreal Neovascularization

Structural En Face OCT Angiography Image of Avulsed Retinal Vessels and Vitreal Neovascularization

Early vascular modifications after endoscopic endonasal pituitary surgery: The role of OCT-angiography.

PurposeThe aim of the present study is to analyze the changes in retinal vessel density (VD), using Optical Coherence Tomography Angiography (OCT-A), in patients that received endoscopic endonasal approach for the removal of an intra-suprasellar pituitary adenoma compressing optic chiasm.MethodsWe evaluated the VD in Superficial Capillary Plexus (SCP), Deep Capillary Plexus (DCP), Radial Peripapillary Capillary (RPC) and the Foveal Avascular Zone (FAZ) area in a series of fourteen patients (7 males, 7 females, mean age 56 ± 13 years), as compared to healthy controls. We also detected the structural Spectral Domain (SD)-OCT parameters: Ganglion Cell Complex (GCC), Retinal Nerve Fiber Layer (RNFL), visual field parameters (Mean Deviation, Pattern Standard Deviation) and Best Corrected Visual Acuity (BCVA). These measurements were performed prior than surgery and 48 hours after.ResultsThe patients showed a significant decrease in VD of the macular and papillary regions, a significant increase in FAZ area, a significant impairment in SD-OCT, VF parameters and BCVA respect to 14 eyes of 14 healthy controls (p<0.05), at pre-op evaluation. In patients group the VD in SCP, DCP and RPC increased after surgery respect to baseline but the difference turned to be out statistically significant only in RPC (p = 0.003). Also the BCVA (p = 0.040) and the Mean Deviation at visual field (p = 0.015) significantly improved after surgery. While there was a reduction in structural OCT parameters but it was statistically significant only in GCC (p = 0.039). A positive correlation was found between the preoperative VD of the RPC, Mean Deviation, BCVA and the postoperative Mean Deviation (r = 0.426 p = 0.027; r = 0.624 p = 0.001; r = 0.515 p = 0.006).ConclusionOCT-A allows to detect the early changes occurring within 48 hours after surgery showing that the improvement in retinal vessel density could occur before the recovery of the structural OCT parameters and can be a positive predictive factor for the functional recovery.

Microvascular impairment as a biomarker of diabetic retinopathy progression in the long-term follow up in type 1 diabetes

This study aimed to explore differences in vascular and structural parameters using optical coherence tomography angiography in patients with type 1 diabetes (DM1) with mild signs of diabetic retinopathy (DR) over a two-year follow-up period. Parafoveal vessel density (PVD) and foveal avascular zone (FAZ) area were analyzed. The thickness of three predefined retinal slabs was measured, including the inner limiting membrane (ILM)–inner plexiform layer (IPL), IPL–inner nuclear layer (INL), and the IPL–outer nuclear layer (ONL). Twenty-two patients with DM1 and 21 controls were included. There was no significant difference in the FAZ area, perimeter and acircularity index between cohorts over time. Baseline superficial capillary plexus PVD was approximately 10% lower in patients with diabetes than in controls (p = 0.001), and was 12% lower at 2 years (p = 0.002). There was no difference in the annual linear trend between the groups (− 0.5% in diabetics vs. controls, p = 0.736). Baseline deep capillary plexus (DCP) PVD was slightly lower in diabetics than in controls (− 4.4%, p = 0.047) and the difference increased at 2 years (− 12.6%, p < 0.001). The annual linear trend was − 2.7% in diabetic patients compared to controls (p = 0.009). In addition, the PVD of the DCP and the intermediate capillary plexus (ICP) were evaluated separately. Regarding the DCP PVD, no statistically significant difference at any time points in diabetic patients compared to controls and no statistically significant difference in the linear trend was found (p > 0.1). Conversely, no difference was recorded for parafoveal ICP density at individual time points (p > 0.1), but a statistically significant difference in the linear trend over time in diabetic patients compared to controls was recoded (− 3.2% per year, p = 0.001). Despite the apparent intergroup differences at baseline in structural OCT parameters, the differences including ILM–IPL (p = 0.273), IPL–INL (p = 0.708), and IPL–ONL (p = 0.054) were modest and not statistically significant with time. Therefore, the microvascular change of the deeper vessels might be a robust biomarker to evaluate the clinical progression of DR in DM1.

Evaluation of retinochoroidal tissues in third trimester pregnants: An optical coherence tomography angiography study.

The structural and vascular changes in the retina and choroid in women in the third trimester of pregnancy were analyzed using optical coherence tomography angiography (OCTA). Forty women in the third trimester of uncomplicated pregnancy and 40 age-matched healthy women were included. Vascular density (VD) in the superficial and deep capillary plexuses (SCP/DCP), foveal density (FD), and foveal avascular zone (FAZ) area and perimetry measured with OCTA, as well as OCT measurements of central macular thickness (CMT) and choroidal thickness (CT) were compared between the groups. Correlations between structural OCT parameters and vascular OCTA metrics were analyzed. The mean gestational age was 34 (28-41) weeks. Mean age was comparable in the groups (p = 0.732). The pregnant women had significantly higher parafoveal DCP-VD (p = 0.015), FAZ area (p = 0.044), and FD (p = 0.002). Mean subfoveal CT was 21 µm higher in pregnant women but was not significant (p = 0.472). There was no difference in CMT (p = 0.448). FAZ metrics were positively correlated with CT in pregnants and with CMT in the control group (p < 0.05). Parafoveal VD was negatively correlated with CT in the control group (p < 0.05). After adjusting for CT and CMT, the significant difference in VD and FD persisted (p < 0.05), while the difference in FAZ area lost significance (p > 0.05). Considering the effects of the probable covariant factors CMT and CT, systemic changes in pregnant women in their third trimester may cause an increase in VD in the macula and parafoveal DCP.

The long-term effects of anti-vascular endothelial growth factor therapy on the optical coherence tomography angiographic appearance of neovascularization in age-related macular degeneration

BackgroundThe short-term effects of anti-vascular endothelial growth factor (anti-VEGF) treatment on macular neovascularization (MNV) morphology is well described, but long-term studies on morphologic changes and correlation of such changes to the type of MNV have not been conducted. This study aims to determine if different types of MNVs in neovascular AMD (nAMD) behave differently with anti-VEGF treatment as visualized on optical coherence tomography angiography (OCTA).MethodsTreatment-naïve nAMD patients were retrospectively screened for baseline and follow-up OCTA imaging 10 or more months after initial treatment. Images were graded for MNV type, area, activity, mature versus immature vessels, vessel density, presence of atrophy, atrophy location and area. Growth rate was calculated as the percent change in lesion area from baseline over the years of follow-up. In addition, the occurrence of complete regression and the percent of lesions that grew, remained stable, and shrunk per type was also evaluated.ResultsForty-three eyes from 43 patients with a mean follow-up of 2 years were evaluated. On structural OCT, 26 lesions were classified as pure type 1 MNVs, 12 MNVs had a type 2 component, and 5 MNVs had a type 3 component. Of these cases, 2 mixed-type MNVs were considered to have completely regressed. There was no significant differences in MNV area and growth rate between type 1 and type 2 lesions, but all cases of type 3 lesions shrunk in the follow-up period. There was no correlation between the number of injections per year and growth rate, endpoint MNV area or endpoint activity status for any MNV type. There was no significant association between the development of atrophy and the number of injections, baseline MNV area, baseline vessel density, or lesion growth rate.ConclusionsIn nAMD, complete regression of an MNV network exposed to anti-VEGF is rare. This work emphasizes the role of anti-VEGF as anti-leakage rather than vascular regression agents in nAMD.

Choriocapillaris flow deficit associated with intraretinal hyperreflective foci in intermediate age-related macular degeneration.

To evaluate the choriocapillaris (CC) flow deficit (FD) beneath drusen associated with overlying intraretinal hyperreflective foci (HRF). Patients with intermediate age-related macular degeneration (AMD) who had structural spectral-domain optical coherence tomography (SD-OCT) and OCT angiography (OCTA) using the Cirrus HD-OCT with AngioPlex software were retrospectively evaluated. A 6 × 6-mm-volume scan was used for the SD-OCT and OCTA. Post-imaging processing steps included generation of drusen map, identification of HRF, and generation of a signal-compensated CC slab prior to binarization and CC FD computation. The CC OCTA image was aligned with the drusen + HRF map to define regions of interest for CC FD measurement. The CC was quantified below drusen with and without overlying HRF and within a 150-μm-wide ring surrounding the drusen (unaffected by potential HRF-related shadowing), and across the entire 6 × 6 macular region. Fifty-three eyes with intermediate AMD were included, 25 eyes with HRF, and 28 eyes with no HRF. The mean ± SD FD% over the whole 6 × 6 macular region was 41.1 ± 3.4 in eyes with HRF compared with 39.5 ± 3.5 in eyes without HRF (p = 0.001). The mean ± SD CC FD% below drusen with HRF (54.4 ± 9.3) was significantly greater than below drusen without HRF (49.6 ± 9.5; p = 0.001). There was a strong positive correlation between the quantity of HRF and the extent of the CC FD (Pearson correlation = 0.81). Choriocapillaris flow deficits appear to be more severe in eyes with HRF and in particular directly below HRF. As HRF are thought to represent a higher risk or more advanced feature of intermediate AMD, these findings highlight the relationship between the severity of CC FD and overall severity of AMD.

Comparison of different morphologies of choroidal neovascularization evaluated by ocular coherence tomography angiography in age-related macular degeneration.

The clinical implications of different morphologies of choroidal neovascularization (CNV), as evaluated by ocular coherence tomography angiography (OCTA) in neovascular age-related macular degeneration (nAMD), are lacking. To describe the morphology of CNV in nAMD using OCTA, and to compare the visual prognosis and other structural OCT biomarkers between different morphologic patterns. Retrospective cohort study. One hundred and forty eyes with nAMD treated with anti-vascular endothelial growth factor (VEGF). Patients were examined using OCTA prior to and at 3, 6 and 12 months after receiving anti-VEGF therapy. Best-corrected visual acuity (BCVA) and morphologic retinal features. Organized CNV was identified in 110/140 eyes (78.6%) using OCTA. These CNV complexes could be divided into three OCTA patterns: the 'medusa' pattern (n = 41), characterized by branching vessels radiating in all directions; the 'seafan' pattern (n = 43), characterized by branching vessels radiating to one side of the lesion; and the 'tangled' pattern (n = 26), characterized by globular entwined vessels without a main trunk. At baseline, the eyes with the tangled pattern were from younger patients (P = .031) with better BCVA (P = .007). There were also fewer intraretinal cysts (P = .021), less fibrovascular pigment epithelial detachment (P = .009), and more pachychoroid (P = .007) in eyes with the tangled pattern on OCT. At 12 months post-treatment, patients with the tangled CNV pattern also showed greater visual improvement than patients with the other two patterns (P = .049). Using OCTA, distinct morphologies of CNV in nAMD patients were identified. These different patterns might be useful predictors for the prognosis of nAMD patients after anti-VEGF therapy.

Multimodal Imaging Correlation of the Concentric Macular Rings Sign in Foveal Hypoplasia: A Distinctive Henle Fiber Layer Geometry

To expand the multimodal imaging correlation of the concentric macular rings (CMR) sign seen on ultra-widefield fundus photography in patients with foveal hypoplasia. Retrospective case series. Thirty-two patients with foveal hypoplasia who demonstrated the CMR sign on ultra-widefield fundus photography. Inclusion criterion was the presence of a CMR sign detected on ultra-widefield fundus photography. Noninvasive multimodal retinal imaging, including ultra-widefield fundus photography, structural OCT, near-infrared reflectance, and blue fundus autofluorescence, were investigated. Horizontal dense B-scans and en face OCT images were acquired. Evaluation of all patients (n= 32 patients) demonstrated a CMR sign on ultra-widefield fundus photography. Structural OCT scans were consistent with foveal hypoplasia in all patients. En face OCT images acquired at the level of the Henle fiber layer highlighted similar concentric rings around the location of the incipient fovea. The series of concentric rings was not visible at any other level of the macula. A significant correlation was found between the horizontal diameter of the largest outer ring and foveal hypoplasia grades (P < 0.0001). The CMR sign seen on ultra-widefield fundus imaging may be a distinctive feature of foveal hypoplasia and can support this diagnosis, especially in patients in whom OCT cannot be performed (patients with poor fixation or nystagmus or young children). Multimodal imaging correlation suggests that these concentric rings occur exclusively at the level of the Henle fiber layer. This distinctive Henle fiber layer geometry may reflect an arrested development stage in the timeline of foveal maturation.

Structural Characterization of Glaucoma Patients with Low Ocular Blood Flow

ABSTRACT Purpose: There is an unclear relationship between ocular blood flow (OBF) and the structural characteristics of the optic nerve head (ONH) in glaucoma, a multifactorial disease. This study used laser speckle flowgraphy (LSFG) to identify low-OBF glaucoma patients and investigated the ONH in these patients. Materials and Methods: In 533 eyes with glaucoma, we determined confounding factors for LSFG-measured OBF (tissue-area mean blur rate: MT) and corrected MT with a linear mixed-effects model (LMM). Structural ONH data (from fundus stereo photography), OCT data, and clinical characteristics were then compared in patients with corrected MT in the upper and lower quartiles using the LMM. Results: Single regression showed significant correlations between MT and age, spherical equivalent (SE), central corneal thickness (CCT), and a weighted count of retinal ganglion cells (wRGC), but not axial length or systemic blood pressure. Gender also significantly influenced MT; MT was corrected for these correlated factors and also glaucoma type with the LMM. The lower-quartile MT group had a significantly larger cup area and cup-disc area ratio and lower temporal quadrant circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and macular ganglion cell complex (GCC) than the upper-quartile group. Conclusions: Low-OBF glaucoma patients were characterized by a larger cup-disc ratio, and higher susceptibility to damage in the temporal disc and the macular area.

Impact of optical coherence tomography angiography on the non-invasive diagnosis of neovascular age-related macular degeneration.

To investigate the changes in imaging tool practice for the diagnosis of neovascular age-related macular degeneration (nAMD). Retrospective analysis of consecutive patients diagnosed with nAMD in a tertiary care center, over a 6-month period in 2014, 2016, and 2018. Patient demographics were compared. Imaging modalities used in 2014 were fundus photography, fluorescein angiography (FA), and structural spectral-domain optical coherence tomography (SD-OCT), while OCT-angiography (OCT-A) was available from 2015. Imaging tools used in our practice were compared in the 3 cohorts. The 3 cohorts included 163, 99, and 167 patients, respectively. There was no difference in age or gender (mean age 81.7years). OCT-A images were analyzable in 60.5% and 89.7% of patients respectively in 2016 and in 2018. In the 3 cohorts, all patients were imaged with fundus photography and structural OCT. FA was performed in 70.2, 28.8, and 22.1% of patients, respectively. This study showed a shift in practice of imaging tools used for the diagnosis of nAMD, non-invasive tools being increasingly used as the first-line imaging, and FA as the second-line imaging.

CHARACTERISTICS AND CLASSIFICATION OF TYPE 3 NEOVASCULARIZATION WITH B-SCAN FLOW OVERLAY AND EN FACE FLOW IMAGES OF OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

To study B-scan flow overlay and en face flow optical coherence tomography angiography (OCT-A) images of Type 3 neovascularization (NV) and to characterize a staging system for Type 3 NV based on the OCT-A findings. We retrospectively collected data on consecutive treatment-naive eyes with Type 3 NV. All eyes underwent fluorescein angiography, indocyanine green angiography, structural spectral domain OCT, and OCT-A (AngioPlex). Localization and extension of abnormal flows detected by B-scan flow overlay and en face OCT-A images were assessed. Of 24 eyes of 22 patients with Type 3 NV, B-scan flow overlay images showed that 4.2% had telangiectatic flow in the deep retinal layer without outer plexiform layer disruption (Stage 1), 8.3% had downward intraretinal flow and subretinal flow without retinal pigment epithelium disruption (Stage 2), and 87.5% had downward flow and retinal pigment epithelium disruption (Stage 3). Of the Stage 3 eyes, 95.2% showed flow signal penetrating at the site of the retinal pigment epithelium disruption on the B-scan flow overlay images. We showed the characteristics of Type 3 NV using B-scan flow overlay and en face OCT-A images. B-scan flow overlay OCT-A images seem useful to improve the detection and accurate diagnosis of Type 3 NV.

Assessments of vessel density and foveal avascular zone metrics in multiple sclerosis: an optical coherence tomography angiography study.

To investigate optical coherence tomography angiography (OCT-A) findings of foveal avascular zone (FAZ) metrics and macular & peripapillary vessel densities (VD) in subjects with multiple sclerosis (MS). The study design was prospective and cross-sectional. FAZ metrics and VDs of the superficial capillary plexus (SCP), deep capillary plexus (DCP), retinal peripapillary capillary plexus (RPCP) along with the structural OCT measurements were scanned by using the Nidek's RS-3000 Advance in MS patients and healthy controls. All subject also underwent an assessment of visual evoked potentials (VEPs). The relationships between the OCT-A parameters with other clinical findings were analysed. Forty-seven MS patients (94 eyes) and 61 healthy volunteers (122 eyes) were included in this study. Thirty-five eyes of the MS patients had an ON history. The structural OCT measurements were significantly differed between the groups (P < 0.001). All FAZ metrics were inversely correlated with central foveal thickness (CFT) (P < 0.001). The FAZ area and perimeter were inversely correlated with the VD of both SCP and DCP (P < 0.05). The VDs of SCP and DCP were significantly differed between the study groups (P < 0.001). The VEP latency was inversely correlated with the retinal nerve fibre layer, macular and ganglion cell layer thicknesses, the VD of SCP, and the VD of the DCP (P < 0.001). Based on OCT angiography, VDs of macular and peripapillary area may be useful in detecting damage from ON in patients with MS.

Retinal microvasculature in pituitary adenoma patients: is optical coherence tomography angiography useful?

To examine retinal vascular changes in the peripapillary and macular areas in patients with pituitary adenoma (PA) using optical coherence tomography angiography (OCTA). Cross-sectional, retrospective study of 17 consecutive PA patients and 16 healthy subjects. All patients underwent a neuro-ophthalmological examination to assess the presence of optic neuropathy (ON). Static automated perimetry (SAP), macular and optic disc structural OCT [retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC) thicknesses] and OCTA were performed. Pituitary adenoma (PA) patients with ON were compared to those without ON and to healthy subjects. Optic neuropathy (ON) was found in 16 eyes of nine PA patients. Peripapillary vessel density (ppVD) and macular vessel density (VD) in the superficial vascular plexus were significantly decreased in PA eyes with ON, compared to healthy eyes (45.21±5.69 versus 50.52±2.14% and 43.79±5.03% versus 48.96±2.94%, respectively). No significant difference in VD was observed in the macular deep vascular complex (DVC) between groups. Pituitary adenoma (PA) patients with ON had a mean ppVD reduction by 10.51% compared to healthy subjects. RNFL and GCC thicknesses were significantly reduced in PA eyes with ON compared to the other groups. Peripapillary VD (ppVD) significantly correlated with RNFL thickness and SAP mean deviation. Optical coherence tomography angiography showed a significant decrease in ppVD and superficial macular VD in PA eyes with ON compared to healthy eyes, according to RNFL and GCC thinning. Together with the absence of DVC alterations, it may provide further insights into neurovascular coupling.

Structural OCT Signs Suggestive of Subclinical Nonexudative Macular Neovascularization in Eyes with Large Drusen

To further define the structural OCT features described as the "double-layer sign" suggestive of subclinical, nonexudative macular neovascularization (NE-MNV) in asymptomatic eyes with age-related macular degeneration (AMD). Cross-sectional observational study. Participants with large drusen (>125 μm) secondary to AMD in at least 1 eye. Participants in a "discovery" cohort, with known NE-MNV identified on swept-source (SS) OCT angiography (OCTA) and the "double-layer sign" on structural spectral-domain OCT (SD-OCT) imaging, were used to identify characteristic features of this sign. These features were then assessed by masked grading in an "evaluation" cohort of AMD eyes with large drusen to determine the predictive values for NE-MNV. Description of OCT features associated with an increased risk of NE-MNV and their diagnostic and predictive performance. The discovery cohort of 4 eyes revealed that in retinal pigment epithelium (RPE) elevations with a greatest transverse linear dimension of 1000 μm or more, an irregular RPE layer with a height of predominantly less than 100 μm, and a nonhomogenous internal reflectivity as characteristic features of the double-layer sign when NE-MNV was present. We term these collective features as a shallow, irregular RPE elevation (SIRE). Features on OCT images from 233 eyes in the evaluation cohort that were associated significantly with NE-MNV when the RPE elevation was more than 1000 μm in length were: height of the RPE elevation, overall flat or variable morphologic features, RPE layer irregularity, and nonhomogeneous reflectivity (all P ≥ 0.032). Twenty-four eyes (10.3%) were identified with a SIRE. On SS-OCTA imaging, 6 of the 233 eyes were found to have definite NE-MNV, and all 6 graded positively for SIRE (sensitivity, 100%). The absence of SIRE was identified in 209 of 227 eyes without NE-MNV (specificity, 92.1%). The positive predictive value for SIRE was 25% and the negative predictive value was 100%. Eyes whose OCT images display a SIRE sign are at higher risk of having subclinical NE-MNV. SIRE can be used as a screening tool on routine structural OCT imaging. More frequent follow-up and diligent home monitoring is recommended for those with SIRE.

Hybrid Three-Dimensional Visualization of Choroidal Vasculature Imaged by Swept-Source Optical Coherence Tomography.

PurposeTo create hybrid three-dimensional (3D) models of the choroidal vasculature from swept-source optical coherence tomography (SS-OCT) angiography images and to evaluate the model's characteristics.MethodsThis study used prospective, noncomparative case series, including 21 eyes of 21 healthy individuals. The 6 × 6-mm macular area was imaged repeatedly to obtain two cube image sets. Images from structural OCT (OCT-S) and OCT angiography (OCT-A) were exported. After vessel-like structures segmentation from the inverted black and white OCT-S images and the OCT-A images, both types of images were reconstructed in a 3D model. The volumes of the outer choroid and the choroidal vessels were measured after thresholding. The similarities of the segmented choroidal vessels (between OCT-S and OCT-A) and between repeatedly acquired images were measured.ResultsMean vessel volume was 2.227 mm3 (29% of the outer choroidal volume) in OCT-S and 0.848 (11%) in OCT-A when measured after removal of the choriocapillaris equivalent volume. Three percent of the vessel volume in OCT-S and 8.4% of that in OCT-A overlapped. The Dice similarity coefficient of vessel volumes in repeated images from the same individual was 0.863 in OCT-S and 0.485 in OCT-A. The ratio of vessel volume to the outer choroidal volume was invariant in OCT-S but increased in OCT-A in the eyes with long axial length.ConclusionsHybrid 3D vascular models of the choroidal vasculature were reconstructed from OCT-S and OCT-A. The new models should prove useful for volumetric analysis of the choroid.Translational RelevanceHybrid 3D models of the choroidal vasculature enable volumetric analysis and facilitate morphologic evaluation.

SENSITIVITY OF 840-nm SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN DETECTING TYPE 1 NEOVASCULARIZATION ACCORDING TO THE HEIGHT OF THE ASSOCIATED PIGMENT EPITHELIAL DETACHMENT.

To evaluate the ability of optical coherence tomography angiography (OCTA) to detect abnormal vascular blood flow in Type 1 neovascularization (NV) with or without significant pigment epithelial detachment (PED). Consecutive age-related macular degeneration patients with either treatment-naive or anti-vascular endothelial growth factor-treated Type 1 NV were divided into 2 groups based on the PED height on structural OCT: greater than 250 μm (Group 1) versus less than 250 μm (Group 2). Two independent senior retina specialists analyzed the OCTA images (Zeiss Angioplex OCT, Carl Zeiss AG, Jena, Germany) using the automatic slabs alone (first reader) versus automatic and manual segmentation slabs (second reader). In Group 1, 15 men and 42 women, aged from 51 years to 97 years (mean: 87.5), were included. Optical coherence tomography angiography was able to show an abnormal blood flow suggestive of Type 1 NV in 23 (40.3%) of 57 eyes for the first reader and in 32 (56.1%) of 57 eyes for the second reader. In Group 2, 7 men and 30 women, aged from 60 years to 96 years (mean: 80.2), were included. The first and second readers were able to observe an image suggestive of Type 1 NV in 33/37 (89.2%) and 37/37 (100%) of eyes, respectively. The ability of OCTA to detect an abnormal blood flow in Type 1 NV was found to highly depend on the height of the associated PED and the use of manual segmentation slabs. Our results suggest that automatic slabs of OCTA should be interpreted with caution for the diagnosis of vascularized PED. The diagnosis of Type 1 NV using OCTA requires the use of manual segmentation and a multimodal imaging approach, especially when the height of the associated PED is >250 μm.

Age-Related Changes in Choroidal Thickness and the Volume of Vessels and Stroma Using Swept-Source OCT and Fully Automated Algorithms

To determine age-related changes in choroidal thickness and the volume of choroidal vessels and stroma using automated algorithms based on structural swept-source OCT (SS-OCT) scans. Prospective and observational study. The study included 144 normal participants with ages ranging from 20 to 88 years. A previously reported strategy was used to automatically segment the choroid using SS-OCT structural images. Attenuation correction was applied on B-scans to enhance the choroidal contrast and facilitate more accurate automatic segmentation of the 3-dimensional choroidal vessel and stroma. The parameters that we investigated included mean choroidal thickness (MCT), choroidal vessel volume (CVV), choroidal stroma volume (CSV), choroid vascularity index (CVI), and the choroidal stroma-to-vessel volume ratio (CSVR). Correlations between MCT and choroidal vessel metrics of CVV, CSV, CVI, and CSVR were studied. Regional distributions of MCT and CVI were analyzed using a grid centered on the fovea. Age-related changes in MCT, CVV, CSV, and CVI were studied in the entire scanning region, as well as in the subregions of the grids. Age-related changes in MCT, CVV, CSV, and CVI using 6×6-mm and 12×12-mm SS-OCT scans. The automated choroid segmentations were validated against manual segmentations, and MCT measurements were shown to be in good agreement (P < 0.0001). Choroidal vessel volume and CSV showed significant correlations with MCT (all P < 0.0001). Interestingly, CVI and CSVR were constant, with little variation among all participants regardless of age and MCT (61.1±1.8% and 0.64±0.05, respectively). Measurements on 12×12-mm and 6×6-mm scans showed excellent agreement in all scan regions (all P < 0.0001). While choroidal thickness and choroidal volume, which includes both choroidal vessels and stroma, decrease with age (all P < 0.0001), the CVI and CSVR vary little among all ages in all regions. Whereas MCT, CVV, and CSV decrease with age, the CVI and CSVR remain constant in all regions with age. Ongoing studies are using these automated algorithms on SS-OCT structural datasets to investigate the diagnostic usefulness of these choroidal parameters in a myriad of ocular and systemic diseases.