Different types of CNV in exudative AMD can be visualized and differentiated with OCT-A. Type 1 CNV were larger with minor demarcation from the surrounding vasculature and were visible on the slab "mid-choroid", "CC" and "RPE". In contrast, type 2 CNV demonstrated a sharp demarcation from the surrounding vasculature reaching the slab "outer retina".

The study population mainly comprised of patients with mild to moderate DES. Tear film thickness as measured with a custom-built OCT device correlated with subjective symptoms in these patients. In agreement with previous data, the association between other signs and symptoms was weak in the present study. Measurement of TFT with OCT may become a valuable tool in the management of DES patients. (ClinicalTrials.gov number, NCT01753687.)

Purpose To compare signal penetration depth and deep structure-visualization of swept source (SS) and spectral domain (SD)-optical coherence tomography (OCT) with and without enhanced depth imaging (EDI) and B-scan averaging modes. Methods Volume scans were obtained from 20 eyes of healthy volunteers by DRI OCT-1, Spectralis using EDI and B-scan averaging, and Cirrus HD-OCT. The signal penetration depth was measured as the distance between the retinal pigment epithelium and the deepest visible anatomical structure at the foveal center. Visibility and contrast of the choroidoscleral junction and of vascular details within the choroid were assessed across the entire volume using an ordinal scoring scale. Outcome measures were compared using paired t-test and rank-sum test.

Background/aims The purpose of the study was to create a standardised protocol for choroidal thickness measurements and to determine whether choroidal thickness measurements made on images obtained by spectral domain optical coherence tomography (SD-OCT) and swept source (SS-) OCT from patients with healthy retina are interchangeable when performed manually or with an automatic algorithm. Methods 36 grid cell measurements for choroidal thickness for each volumetric scan were obtained, which were measured for SD-OCT and SS-OCT with two methods on 18 eyes of healthy volunteers. Manual segmentation by experienced retinal graders from the Vienna Reading Center and automated segmentation on >6300 images of the choroid from both devices were statistically compared. Results Model-based comparison between SD-OCT/SS-OCT showed a systematic difference in choroidal thickness of 16.26±0.725 μm (p<0.001) for manual segmentation and 21.55±0.725 μm (p<0.001) for automated segmentation. Comparison of automated with manual segmentations revealed small differences in thickness of −0.68±0.513 μm (p=0.1833). The correlation coefficients for SD-OCT and SS-OCT measures within eyes were 0.975 for manual segmentation and 0.955 for automatic segmentation. Conclusion Choroidal thickness measurements of SD-OCT and SS-OCT indicate that these two devices are interchangeable with a trend of choroidal thickness measurements being slightly thicker on SD-OCT with limited clinical relevance. Use of an automated algorithm to segment choroidal thickness was validated in healthy volunteers.

The aim of this pilot study was to test whether mathematical parameters of the vascular morphology of choroidal neovascularization (CNV) can be used as biomarkers and to investigate how these parameters change during anti-vascular endothelial growth factor (VEGF) therapy. Methods Treatment-naive CNV in exudative age-related macular degeneration (AMD) was diagnosed in 28 patients. OCTangiography (OCT-A) (Avanti/FA Optovue) performed before and after anti-VEGF therapy. The OCT-A data sets were exported to an external image processing program and vessel skeletonization was accomplished by means of edge detection. Based on this technique the total vessel length, the number of segments and the fractal dimension (FD) of the CNV were calculated before and after therapy. The results were compared with other clinical parameters such as VA and central retinal thickness (RT). Results The total vessel length of the CNV was significantly reduced by anti-VEGF-therapy (mean value 652 pixels vs. 397 pixels; p < 0.0001), as well as the number of individual vessel segments of the CNV (mean value 117 vs. 76; p < 0.0001). The FD of the CNV also decreased significant reduction during therapy (mean 1.23 vs. 1.16, p < 0.0001). The changes in these parameters during treatment corresponded with an increase in VA and a reduction in RT. Conclusion This pilot study demonstrates that the vascular pattern of CNV in AMD can be visualized and described using mathematical parameters of OCT-A. The changes during therapy correlate significantly with established "activity" parameters of CNV, so changes in these parameters (especially FD) may represent additional CNV "activity" biomarkers.

ObjectiveOptical coherence tomography angiography (OCT-A) enables detailed visualisation of the vascular structure of choroidal neovascularisation (CNV). The aim of this study was to determine whether mathematically ascertained OCT-A vascular parameters of type 1 and type 2 CNV in exudative age-related macular degeneration (AMD) change during antivascular endothelial growth factor (anti-VEGF) treatment. The OCT-A vascular parameters were also compared with previously obtained activity parameters (fluid distribution on spectral domain OCT (SD-OCT)) to establish whether they could potentially be used as further ‘activity parameters’ for assessment of anti-VEGF treatment.Methods and AnalysisWe evaluated 27 eyes of 27 patients (mean follow-up 9.8 months) with type 1, type 2 or mixed CNV who had received anti-VEGF treatment (IVAN scheme). The parameters analysed were area (aCNV), total length of all vessels (tlCNV), overall number of vascular segments (nsCNV) and fractal dimension (FD) of the CNV. The changes in each of these parameters were correlated with the central foveal thickness (CFT).ResultsRegression and renewed perfusion of the CNV corresponded with the decrease or increase, respectively, of macular fluid distribution on SD-OCT. The increase and decrease of CFT during anti-VEGF treatment were highly significantly correlated with changes in FD (p<0.00001), aCNV (p<0.00001), tlCNV (p<0.00001) and nsCNV (p<0.00001).ConclusionOCT-A enables detailed analysis of AMD with regard to FD, aCNV, tlCNV and nsCNV. As the changes in these parameters correlate closely with changes on SD-OCT, they can be used as new activity parameters, alongside fluid distribution, for assessment of treatment effect and as parameters of stabilisation or the need for repeated treatment.

BackgroundRetinal neovascularization (RNV) membranes can lead to a tractional retinal detachment, the primary reason for severe vision loss in end-stage disease proliferative diabetic retinopathy (PDR). The aim of this study was to characterize the molecular, cellular and immunological features of RNV in order to unravel potential novel drug treatments for PDR.MethodsA total of 43 patients undergoing vitrectomy for PDR, macular pucker or macular hole (control patients) were included in this study. The surgically removed RNV and epiretinal membranes were analyzed by RNA sequencing, single-cell based Imaging Mass Cytometry and conventional immunohistochemistry. Immune cells of the vitreous body, also known as hyalocytes, were isolated from patients with PDR by flow cytometry, cultivated and characterized by immunohistochemistry. A bioinformatical drug repurposing approach was applied in order to identify novel potential drug options for end-stage diabetic retinopathy disease.ResultsThe in-depth transcriptional and single-cell protein analysis of diabetic RNV tissue samples revealed an accumulation of endothelial cells, macrophages and myofibroblasts as well as an abundance of secreted ECM proteins such as SPARC, FN1 and several types of collagen in RNV tissue. The immunohistochemical staining of cultivated vitreal hyalocytes from patients with PDR showed that hyalocytes express α-SMA (alpha-smooth muscle actin), a classic myofibroblast marker. According to our drug repurposing analysis, imatinib emerged as a potential immunomodulatory drug option for future treatment of PDR.ConclusionThis study delivers the first in-depth transcriptional and single-cell proteomic characterization of RNV tissue samples. Our data suggest an important role of hyalocyte-to-myofibroblast transdifferentiation in the pathogenesis of diabetic vitreoretinal disease and their modulation as a novel possible clinical approach.

No abstract