Association between choriocapillaris flow deficit and choroidal neovascularization activity in eyes with myopic choroidal neovascularization

Although choriocapillaris flow deficit (CFD) around choroidal neovascularization (CNV) is less associated with CNV activity in myopic eyes, no reports are investigating its size as an indicator of CNV activity. We investigated the relationship between CFD and high myopia-related CNV. In this retrospective, observational study, patients underwent optical coherence tomography angiography (OCTA) with split-spectrum amplitude-decorrelation angiography for diagnosing pathological myopic CNV (mCNV); CFD features around CNV margins were evaluated. Of the 33 eyes (30 patients), 11 (33.3%) had active mCNV, and 22 (66.7%) had inactive CNV. Six eyes (18.2%) were treatment-naïve, while the remainder previously underwent anti-vascular endothelial growth factor therapy. On OCTA, blood flow signals were detected in CNV in the outer retinal layer in 28 (84.8%) eyes, including all active cases (11 cases) and 17 (77.3%) of 22 inactive cases. CNV flow signal size correlated significantly with activity (P < 0.001). CFD around CNV was observed in 24 eyes (72.7%), including all active cases (11 cases) and 13 (59.1%) of 22 inactive cases. CFD size correlated significantly with CNV activity (P < 0.001). The size of both the CFD area around CNV and CNV flow signal area are useful indicators of CNV activity in eyes with mCNV, which may help determine treatment timing.

Strain accumulation along various faults in the Kashmir Himalaya from InSAR

&lt;p&gt;We are using InSAR time-series analysis to measure the interseismic deformation across various faults of the Kashmir Himalaya. Active faults reaching the surface include the Main Boundary Faults, Bagh-Balakot Fault, which ruptured in the 2005 Kashmir earthquake (Mw 7.6), Jhelum Fault, Reasi Thrust and intra-Kashmir basin faults. We concentrate on these shallow faults that are closest to the people living in Kashmir. The Main Boundary Faults and other faults likely connect to the Main Himalayan Thrust (MHT) that is the plate-boundary megathrust beneath Kashmir and the rest of the Himalayas. The MHT has been suggested as a possible source for Mw 8 to Mw 8.5 earthquakes in this area. We have processed interferometric pairs from the Japan Aerospace Exploration Agency ALOS-2 L-band (24 cm wavelength) Synthetic Aperture Radar (SAR) wide-swath (ScanSAR) data acquired between 2015 and 2020. Initial interferometric SAR (InSAR) processing was carried out using the alos2App application of the InSAR Scientific Computing Environment (ISCE2) package, with ionospheric corrections enabled. We found that many scenes acquired in the winter form pairs that have low coherence due to snow cover in the High Himalayas and Pir Panjal Range. We also found that phase unwrapping in the mountains was improved by taking 10 range and 56 azimuth looks from the full-aperture ScanSAR for an effective resolution of about 200 meters. We are running a co-registered stack processing of the ALOS-2 SAR data, with self-consistent ionospheric corrections estimated using the split-spectrum method, using the new alosStack application of ISCE2 package to carry out time-series InSAR analysis, using an open-source Python toolbox, MIntPy.&lt;/p&gt;

Association between choriocapillaris flow deficit and choroidal neovascularization activity in eyes with myopic choroidal neovascularization

Although choriocapillaris flow deficit (CFD) around choroidal neovascularization (CNV) is less associated with CNV activity in myopic eyes, there are no reports investigating its size as an indicator of CNV activity. We investigated the relationship between CFD and high myopia-related CNV. In this retrospective, observational study, patients underwent optical coherence tomography angiography (OCTA) with split-spectrum amplitude decorrelation angiography for diagnosing pathological myopic CNV (mCNV); CFD features around CNV margins were evaluated. Of the 33 eyes (30 patients), 11 (33.3%) had active mCNV, and 22 (66.7%) had inactive CNV. Five eyes (15.2%) were treatment-naïve, while the remainder previously underwent anti-vascular endothelial growth factor therapy. On OCTA, blood flow signals were detected in CNV in the outer retinal layer in 28 (84.8%) eyes, including all active cases (11 cases) and 17 (77.3%) of 22 inactive cases. CNV flow signal size correlated significantly with activity (P = 0.002). CFD around CNV was observed in 18 eyes (54.5%), eight of which had active CNV. CFD size correlated significantly with CNV activity (P = 0.014). The size of both the CFD area around CNV and CNV flow signal area are useful indicators of CNV activity in eyes with mCNV, which may help determine treatment timing.

Peripapillary perfused capillary density in true versus pseudoexfoliation syndrome: An OCTA study

Purpose To compare peripapillary perfused capillary density (PCD) among eyes with true exfoliation syndrome (TEX), eyes with pseudoexfoliation syndrome (PEX), and healthy control eyes. Materials and methods In this observational cross-sectional study, eyes with and without TEX or PEX were assessed by optical coherence tomography angiography (OCTA) imaging. Bilateral OCTA images (4.5 × 4.5 mm2) centered at the optic nerve head were obtained using a commercial spectral domain OCTA system. Optic nerve head perfusion was quantified using the split-spectrum amplitude decorrelation angiography algorithm. Categorical and continuous variables were compared using the chi-squared test and one-way analysis of variance, respectively. The generalized estimating equation was used to adjust for confounding factors and determine inter-ocular associations. Results We enrolled 39 eyes with TEX, 31 eyes with PEX, and 32 control eyes. There were no significant differences among the three groups regarding age, intraocular pressure, cup-to-disc ratio, blood pressure, or axial length (all p>0.05). There were significant differences in global PCD among the three groups (p = 0.01). There were significant differences in annular PCD between the TEX and PEX groups (p = 0.027). Conclusions While both global and annular PCDs did not differ between the TEX and control groups, greater loss of annular PCD in the PEX group than in the TEX and control groups suggests more pronounced microvascular disturbance in PEX. Synopsis/Precis Greater microvascular attenuation in PEX compared with TEX and normal control measured by OCTA.

Peripapillary Perfused Capillary Density in True Versus Pseudoexfoliation Syndrome: An OCTA Study

PurposeTo compare peripapillary perfused capillary density (PCD) among eyes with true exfoliation syndrome (TEX), eyes with pseudoexfoliation syndrome (PEX), and healthy control eyes.Materials and MethodsIn this observational cross-sectional study, eyes with and without TEX or PEX were assessed by optical coherence tomography angiography (OCTA) imaging. Bilateral OCTA images (4.5 · 4.5 mm2) centered at the optic nerve head were obtained using a commercial spectral domain OCTA system. Optic nerve head perfusion was quantified using the split-spectrum amplitude decorrelation angiography algorithm. Categorical and continuous variables were compared using the chi-squared test and one-way analysis of variance, respectively. The generalized estimating equation was used to adjust for confounding factors and determine inter-ocular associations.ResultsWe enrolled 39 eyes with TEX, 31 eyes with PEX, and 32 control eyes. There were no significant differences among the three groups regarding age, intraocular pressure, cup-to-disc ratio, blood pressure, or axial length (all p>0.05). There were significant differences in global PCD among the three groups (p=0.01). There were significant differences in annular PCD between the TEX and PEX groups (p=0.027).ConclusionsWhile both global and annular PCDs did not differ between the TEX and control groups, greater loss of annular PCD in the PEX group than in the TEX and control groups suggests more pronounced microvascular disturbance in PEX.Synopsis/PrecisGreater microvascular attenuation in PEX compared with TEX and normal control measured by OCTA.