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The purpose of the study was to evaluate the retinal blood flow in patients with acute central serous chorioretinopathy (CSC) over an observational period of 1 month using swept-source optical coherence tomography (SS-OCTA), focusing especially on changes in the area of subretinal fluid (A-SRF). We correlated these findings with conventional indocyanine green angiography (ICGA). ICGA and SS-OCTA images were collected and analyzed of 12 eyes of 12 patients. The A-SRF was annotated and a qualitative analysis of choriocapillaris, the vessel density (VD) and perfusion density (PD) of the retinal superficial capillary plexus (SCP) and the deep capillary plexus (DCP) was performed in A-SRF and the unaffected remaining area (RA). The VD and PD in the DCP were statistically significantly lower in A-SRF than in the RA at baseline. (VD: p = 0.014; PD: p = 0.036). After 1 month, there was a statistically significant difference in the VD and PD of the DCP (VD: p = 0.015; PD: p = 0.014), and for the PD of the SCP between the A-SRF and the RA (p = 0.015), with lower values in the A-SRF. We found low perfused areas in choriocapillaris corresponding to hypofluorescent areas on ICGA. In conclusion there is a difference in VD and VD of the DCP in the area of SRF in acute CSC. These alterations may lead to a chronic change in the microvasculature and potentially to morphological changes.

Purpose To investigate the characteristics of treatment-naive nonexudative macular neovascularization (MNV) in age-related macular degeneration before the onset of exudation using swept-source optical coherence tomography angiography. Methods MNV area, choriocapillaris (CC) flow deficits (FDs), vessel area density (VAD), vessel skeleton density (VSD), retinal pigment epithelial detachment (PED) volume, mean choroidal thickness (MCT), and choroid vascularity index (CVI) measurements were assessed at two visits prior to exudation. We compared measurements made at the second visit and the rate of change between visits in eyes with and without exudation. The differences in these parameters between eyes with and without subsequent exudation were summarized with 95% confidence intervals (CIs). Results Twenty-one eyes with nonexudative MNV were identified and followed. Nine eyes developed exudation, and 12 eyes did not develop exudation. Differences between these groups of eyes for all parameters tended to be small, and the 95% CIs largely ruled out any substantial differences. Overall, eyes with exudation had 24% smaller VAD, 20% smaller VSD, and 33% smaller PED volume measurements. No noteworthy differences were observed for MNV area, CC FDs, MCT, or CVI measurements. Conclusions The onset of exudation was correlated with lesions having less vascularity and smaller PED volume measurements, but measurements of MNV area, CC FDs, MCT, and CVI were not correlated with near-term exudation. Investigations are ongoing to further explore these and other anatomic changes as harbingers of near-term exudation.

To examine retinal vessel closure metrics and neurodegenerative changes occurring in the initial stages of nonproliferative diabetic retinopathy (NPDR) and severity progression in a three-year period. Methods: Three-year prospective longitudinal observational cohort of individuals with type 2 diabetes (T2D), one eye per person, using spectral domain-optical coherence tomography (SD-OCT) and OCT-Angiography (OCTA). Eyes were examined four times with one-year intervals. OCTA vessel density maps of the retina were used to quantify vessel closure. Thickness of the ganglion cell + inner plexiform layer (GCL + IPL) was examined to identify retinal neurodegenerative changes. Diabetic retinopathy ETDRS classification was performed using the seven-field ETDRS protocol. Results: A total of 78 eyes/patients, aged 52 to 80 years, with T2D and ETDRS grades from 10 to 47 were followed for 3 years with annual examinations. A progressive increase in retinal vessel closure was observed. Vessel density (VD) showed higher decreases with retinopathy worsening demonstrated by step-changes in ETDRS severity scale (p &lt, 0.001). No clear correlation was observed between neurodegenerative changes and retinopathy progression. Conclusions: Retinal vessel closure in NPDR correlates with DR severity progression. Our findings provide supporting evidence that OCTA metrics of vessel closure may be used as a surrogate for DR severity progression.

To enhance the rapid assessment of geographic atrophy (GA) across the macula in a single projection image generated from three-dimensional (3D) spectral-domain optical coherence tomography (SD-OCT) scans by introducing a novel restricted summed-area projection (RSAP) technique.We describe a novel en face GA visualization technique, the RSAP, by restricting the axial projection of SD-OCT images to the regions beneath the Bruch's membrane (BM) boundary and also considering the choroidal vasculature's influence on GA visualization. The technique analyzes the intensity distribution beneath the retinal pigment epithelium (RPE) layer to fit a cross-sectional surface in the sub-RPE region. The area is taken as the primary GA projection. A median filter is then adopted to smooth the generated GA projection image. The RSAP technique was evaluated in 99 3D SD-OCT data sets from 27 eyes of 21 patients presenting with advanced nonexudative age-related macular degeneration and GA. We used the mean difference between GA and background regions and GA separability metric to measure GA contrast and distinction in the generated images, respectively. We compared our results with two existing GA projection techniques, the summed-voxel projection (SVP) and Sub-RPE Slab techniques.Comparative results demonstrate that the RSAP technique is more effective in displaying GA than the SVP and Sub-RPE Slab. The average of the mean difference between GA and background regions and the GA separability based on SVP, Sub-RPE Slab, and RSAP were 0.129/0.880, 0.238/0.919, and 0.276/0.938, respectively.The RSAP technique was more effective for GA visualization than the conventional SVP and Sub-RPE Slab techniques. Our technique decreases choroidal vasculature influence on GA projection images by analyzing the intensity distribution characteristics in sub-RPE regions. The generated GA projection image with the RSAP technique has improved contrast and distinction.Our method for automated generation of GA projection images from SD-OCT images may improve the visualization of the macular abnormalities and the management of GA.

Understanding the healing process after surgery for closure of macular holes (MHs) may provide insight into maximizing surgical success and predicting visual acuity (VA) outcomes. Spectral-domain optical coherence tomography (SD-OCT) is a widely used noninvasive, medical imaging technique to provide in vivo high resolution, cross-sectional three-dimensional images of the retina,1–5 allowing ophthalmologists to identify and quantify macular abnormalities in various vitreoretinal diseases such as MHs,6 providing valuable information before7 and after MH surgery,8 or to even assist intraoperatively.9,10 Advances in SD-OCT instrumentation and image analysis methods have led to the development of numerous automated intraretinal segmentation methods, both in commercial systems11 or by research groups,12–20 and tools to quantify macular disease progression.21 However, analysis of postoperative SD-OCT data in MH patients has not moved significantly beyond the manual annotation of defects in a single two-dimensional horizontal-scan through the foveal center.22 This manual assessment has two fundamental issues: The largest width of a defect may lie in an oblique axis,6 making measurements in horizontal-scans unreliable, and the lack of standardized measuring criteria adds an element of subjectivity when judging margins,22 leading to potential ambiguity. These issues may be the cause of ambiguity between previous reports studying the association of the integrity of the photoreceptor ellipsoid zone (EZ) band or the external limiting membrane (ELM)22–30 with VA in surgically anatomically closed MHs. While some studies demonstrated statistically significant correlation of VA with the diameter and area of EZ band defects,22–26 others reported no such correlation and gave more importance to defects involving the ELM.27–29 Another study did not find correlation of VA with either EZ band or ELM defects at times later than 6 months after surgery, but instead found correlation with the cone outer segment tips (COST) line.30 Findings predicting potential restoration of VA in surgically closed MHs have also not been sufficiently clarified. A study showed that a higher diameter of EZ band defects measured at 3 months after surgery was associated with poorer VA at 12 months,31 while others found such association not to be significant, but found that less extensive ELM defects measured shortly after surgery may indicate a higher chance of vision restoration at 626 or 12 months.28 Defects in the inner retinal layers, such as the nerve fiber layer (NFL), the ganglion cell complex (GCL), or the inner plexiform layer (IPL), mainly occurring in the temporal region, have also been reported and associated to lower visual function.32 Postsurgical inner retina defects, mainly caused by inner limiting membrane (ILM) peeling during the surgical procedure33 or by dye toxicity during intraoperative staining32,34 can be observed in SD-OCT images as localized dips in the ILM boundary translating in isolated regions of inner retina (IR) thinning23,28,34,35 with higher incidence in the supero-temporal region.36 However, such chronically persisting defects33 have not correlated with VA23,28 and an association with poorer vision recovery has also not been observed.28 This lack of association may be due to the limitations mentioned previously. Topographic measurements of postoperative defects in SD-OCT-derived en face images have been shown to be more reliable, with greater correlation with VA than when measured in cross-sectional images,22 and a robust automated method would eliminate subjective judgment. We have developed automated methods to quantify defects in the EZ band and the inner retina by extracting a set of image features related to defect topographic extent and location. We examined the correlation of these imaging features with VA in postoperative MH longitudinal SD-OCT scans, eliminating any subjective judgment and ambiguities derived from making measurements manually in cross-sectional scans.

Hydroxychloroquine (HCQ) is toxic to the retina in proportion to daily dose and duration of use, causing a characteristic retinopathy in Caucasian patients with loss of photoreceptors and eventually RPE changes in a ring around the fovea.1,2 The mechanism of this toxicity is unclear, as animal experiments have shown the drug can affect all retinal layers,3 whereas the damage seen in clinical imaging is primarily to the outer retina.4 We showed recently that HCQ retinopathy can progress even after the drug is stopped, sometimes for years, but that the degree of progression is related to the severity of retinopathy and is minimal when the toxicity is detected at early stages of damage.5 However, that study left a number of important questions unanswered, including the relative involvement of inner and outer retina, the relative involvement of parafovea and peripheral fovea, and potential differences between progression of retinopathy while using the drug or after stopping the drug. The present report addresses these issues and presents new results. Some previous reports have suggested mild inner retina damage during HCQ usage as observed in spectral-domain optical coherence tomography (SD-OCT) images.6–8 However, we have identified technical limitations in a commonly used commercial ganglion cell segmentation program in SD-OCT images in the presence of focal damage to the outer retina, which led us to use an experimental pixel-by-pixel segmentation paradigm and address this issue with more accurate segmentation of the retinal layers. Previous studies of HCQ retinopathy also have focused on damage to the parafovea, whereas in this report we address the nature of damage more broadly in the macula, differentiating between damage to the center of the fovea, parafovea, and the peripheral fovea ring, as well in pixel-by-pixel topographic macula maps. We also compare patterns of macular damage between different stages of maculopathy while using HCQ to the way maculopathy progresses after cessation of HCQ.

Geographic atrophy (GA) is a condition that is associated with retinal thinning and loss of the retinal pigment epithelium (RPE) layer. It appears in advanced stages of non-exudative age-related macular degeneration (AMD) and can lead to vision loss. We present a semi-automated GA segmentation algorithm for spectral-domain optical coherence tomography (SD-OCT) images. The method first identifies and segments a surface between the RPE and the choroid to generate retinal projection images in which the projection region is restricted to a sub-volume of the retina where the presence of GA can be identified. Subsequently, a geometric active contour model is employed to automatically detect and segment the extent of GA in the projection images. Two image data sets, consisting on 55 SD-OCT scans from twelve eyes in eight patients with GA and 56 SD-OCT scans from 56 eyes in 56 patients with GA, respectively, were utilized to qualitatively and quantitatively evaluate the proposed GA segmentation method. Experimental results suggest that the proposed algorithm can achieve high segmentation accuracy. The mean GA overlap ratios between our proposed method and outlines drawn in the SD-OCT scans, our method and outlines drawn in the fundus auto-fluorescence (FAF) images, and the commercial software (Carl Zeiss Meditec proprietary software, Cirrus version 6.0) and outlines drawn in FAF images were 72.60%, 65.88% and 59.83%, respectively.