SCP Vessel Density Research Articles

Diagnostic Capability of OCTA-Derived Macular Biomarkers for Early to Moderate Primary Open Angle Glaucoma.

Background/Objectives: To investigate macular vascular biomarkers for the detection of primary open-angle glaucoma (POAG). Methods: A total of 56 POAG patients and 94 non-glaucomatous controls underwent optical coherence tomography angiography (OCTA) assessment of macular vessel density (VD) in the superficial (SCP), and deep (DCP) capillary plexus, foveal avascular zone (FAZ) area, perimeter, VD, choriocapillaris and outer retina flow area. POAG patients were classified for severity based on the Glaucoma Staging System 2 of Brusini. ANCOVA comparisons adjusted for age, sex, race, hypertension, diabetes, and areas under the receiver operating characteristic curves (AUCs) for POAG/control differentiation were compared using the DeLong method. Results: Global, hemispheric, and quadrant SCP VD was significantly lower in POAG patients in the whole image, parafovea, and perifovea (p < 0.001). No significant differences were found between POAG and controls for DCP VD, FAZ parameters, and the retinal and choriocapillaris flow area (p > 0.05). SCP VD in the whole image and perifovea were significantly lower in POAG patients in stage 2 than stage 0 (p < 0.001). The AUCs of SCP VD in the whole image (0.86) and perifovea (0.84) were significantly higher than the AUCs of all DCP VD (p < 0.05), FAZ parameters (p < 0.001), and retinal (p < 0.001) and choriocapillaris flow areas (p < 0.05). Whole image SCP VD was similar to the AUC of the global retinal nerve fiber layer (RNFL) (AUC = 0.89, p = 0.53) and ganglion cell complex (GCC) thickness (AUC = 0.83, p = 0.42). Conclusions: SCP VD is lower with increasing functional damage in POAG patients. The AUC for SCP VD was similar to RNFL and GCC using clinical diagnosis as the reference standard.

Microvascular Changes after Epiretinal Membrane Vitrectomy with Intraoperative Intravitreal Dexamethasone Implant: An OCT Angiography Analysis.

We aimed to explore microvascular changes evaluated with optical coherence tomography angiography (OCTA) in patients undergoing epiretinal membrane (ERM) pars-plana vitrectomy (PPV) combined with intravitreal Ozurdex implantation, compared with standard PPV. (2) Methods: Prospective interventional analysis on 25 eyes undergoing PPV + Ozurdex (Group A) and 25 eyes undergoing PPV alone. Best corrected visual acuity (BCVA) and OCTA parameters, such as vessel density (VD) of the superficial and deep capillary plexi (SCP and DCP) in the whole 6.4 mm × 6.4 mm and fovea area, were evaluated preoperatively and 3 months after surgery. (3) Results: Postoperative BCVA significantly improved in both groups. No cases of post-operative cystoid macular edema (CME) were reported in Group A vs. two eyes in Group B. In Group A we found a statistically significant increase of SCP's VD in either the whole image (from 42.1 ± 4.1 to 45.6 ± 4.3%, p = 0.01) and the fovea image (from 38.5 ± 7.5 to 41.7 ± 4.2%, p = 0.03). In Group B, we reported no significant variations in the SCP's VDs. In the DCP, VD significantly increased only in the whole image in Group A. Stage 4 ERMs showed the greatest improvement in VD, especially in Group A. (4) Conclusions: Intraoperative Ozurdex prompted a significant BCVA recovery and limited the occurrence of postoperative CME compared to the standard procedure. Moreover, Ozurdex implant is associated with a better restoration of microvascular structure in SCP and DCP.

Retinal structural and microvascular deterioration independent of optic neuritis in aquaporin-4 antibody-positive neuromyelitis optica spectrum disorders: An optical coherence tomography angiography study

PurposeTo assess the retinal structural and microvascular change in aquaporin-4 antibody (AQP4) positive neuromyelitis optica spectrum disorder (NMOSD) patients and the correlation with clinical features. MethodsA cross-sectional study was performed with optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) to measure retinal structure and microvascular parameters in AQP4 positive NMOSD patients. ResultsSixty-two NMOSD patients (44 eyes with ON, NMOSD+ON; 77 eyes without ON, NMOSD-ON) and 62 healthy controls (HC, 124 eyes) were included. BCVA was worse in NMOSD patients compared to HC (p<0.001). Peripapillary retinal nerve fiber layer (pRNFL, p<0.001) and ganglion cell complex (GCC, p<0.001) was thinner in NMOSD+ON eyes compared to NMOSD-ON eyes and HC. Compared to HC, pRNFL (p = 0.002) and GCC (p = 0.001) was thinner in NMOSD-ON eyes. The vessel density (VD) in superficial capillary plexus (SCP, NMOSD+ON vs HC p<0.001, NMOSD-ON vs HC p = 0.002) and radial peripapillary capillary (RPC, NMOSD+ON vs HC p<0.001, NMOSD-ON vs HC p = 0.001) were also lower in NMOSD patients than HC independent of the history of ON. ON frequency and BCVA were correlated with the thickness of pRNFL and GCC, and VD in SCP and RPC (all p<0.001). EDSS was correlated with thickness of GCC (p = 0.008), and VD in SCP (p = 0.013), DCP (p<0.001) and RPC (p = 0.009). ConclusionsSubclinical degradation of retinal structure and microvasculature was found in NMOSD patients before the occurrence of ON, and was correlated with clinical disability. Retinal parameter might be a tool to estimate the disease progression and investigate the pathogenesis of NMOSD.

Long-term real-world outcomes of retinal microvasculature changes in proliferative diabetic retinopathy treated with panretinal photocoagulation vs. intravitreal conbercept

PurposeTo compare long-term real-world outcomes of retinal microvasculature changes in proliferative diabetic retinopathy (PDR) treated with panretinal photocoagulation (PRP) vs. intravitreal conbercept (IVC) and to explore the potential factors affecting these changes. MethodsThis study retrospectively included 96 treatment-naïve PDR eyes of 96 type 2 diabetes mellitus patients [59 PRP and 37 IVC]. Baseline characteristics and treatment details were collected. Optical coherence tomography angiography (OCTA) data of macular vessel density (VD) and optic disc capillary density (CD) at baseline and at the last follow-up were compared between groups. The differences between the baseline and the last follow-up OCTA data in each group were also tested for significance. The correlation between the change in each OCTA parameter from baseline and each baseline characteristic/treatment parameter was investigated in each group. ResultsDuring a mean follow-up of two years, greater superficial (SCP) (p = 0.004) and deep capillary plexus (DCP) VD (p < 0.001) were observed in the foveal area in the PRP than in the IVC. Compared to the baseline, SCP VD in the foveal area increased in the PRP (p = 0.012), while an increased SCP VD in some sectors in the parafoveal and perifoveal areas (p < 0.05), rather than the foveal area (p = 0.908), was seen in the IVC. For both groups, eyes with a higher VD/CD at baseline tended to develop capillary dropout more intensively (all p < 0.05). In the IVC group, foveal avascular zone (FAZ) area change showed a negative correlation with baseline FAZ area (p = 0.020), and complementary PRP exerted a negative influence on FAZ area change (p = 0.002). In the PRP group, SCP VD change was positively correlated with follow-up frequency, and was negatively correlated with diastolic blood pressure (all p < 0.05); DCP VD change showed a positive correlation with PRP shot number (p = 0.019). ConclusionThe aforementioned microvasculature changes should be considered when PRP or IVC is adopted in PDR long-term management.

Retinal and choroidal microvascular changes during pregnancy detected with OCTA

ObjectifExaminer les variations du débit sanguin dans la choroïde et la rétine de même que l’épaisseur de ces structures grâce à la tomographie par cohérence optique (OCT, pour optical coherence tomography) et à l'angiographie-tomographie par cohérence optique (OCTA, pour optical coherence tomography angiography) pendant la grossesse. NatureÉtude cas-témoins prospective réalisée entre juin 2020 et juin 2021. MéthodesLa présente étude prospective portait sur 41 yeux de 41 femmes enceintes et sur 45 yeux de 45 femmes non enceintes en bonne santé. La pression de perfusion oculaire, l’épaisseur de la rétine, l’épaisseur de la choroïde, l'aire de la zone fovéale avasculaire (ZFA), les plexus capillaires superficiel et profond (PCS et PCP, respectivement), la densité vasculaire (DV) et la DV de la choriocapillaire (CC) ont été évalués par OCT et OCTA. RésultatsOn n'a pas observé de différence significative au chapitre de la pression de perfusion oculaire, de l’épaisseur de la rétine et de l’épaisseur de la choroïde pendant la grossesse. L'aire de la ZFA augmentait à mesure que la grossesse progressait (p = 0,011). Pendant le premier trimestre, l'aire de la ZFA était significativement plus petite que chez les patientes du groupe témoin (p = 0,029). Cependant, on a noté une diminution de la DV du PCS et du PCP pendant le troisième trimestre et une augmentation de la DV de la CC pendant toute la grossesse (p = 0,01; p < 0,001 et p < 0,001, respectivement). Il s'est produit une hausse de la DV moyenne tant dans le PCS que dans le PCP pendant le deuxième trimestre (p = 0,02 et p = 0,027, respectivement). La DV du PCS et du PCP était significativement plus élevée pendant le deuxième et le troisième trimestre que chez les témoins. Enfin, une élévation significative de la DV de la CC a été enregistrée pendant la grossesse. ConclusionIl s'agit de la première étude prospective publiée à faire appel à l'OCTA pour évaluer ces mesures pendant les trois trimestres de la grossesse. Nous avons observé des modifications microvasculaires significatives dans la rétine et la choroïde entre les différents trimestres de la grossesse, de même qu'entre les femmes enceintes et les femmes en bonne santé qui n’étaient pas enceintes.

Quantitative assessment of retinal microvascular remodeling in eyes that underwent idiopathic epiretinal membrane surgery.

Purpose: To explore the surgical outcomes of the macular microvasculature and visual function in eyes with idiopathic epiretinal membrane (iERM) using spectral-domain optical coherence tomography angiography (SD-OCTA). Methods: This observational, cross-sectional study included 41 participants who underwent iERM surgery with a 3-month (3M) follow-up. Forty-one healthy eyes formed the control group. The assessments included best-corrected visual acuity (BCVA) and mean sensitivity (MS) by microperimetry and SD-OCTA assessment of vessel tortuosity (VT), vessel density (VD), foveal avascular zone, and retinal thickness (RT). Results: The findings showed statistically significant differences in VT, foveal avascular zone parameters, RT, BCVA, and MS between the iERM and control groups (p < 0.05). After iERM surgery, the macular VT, SCP VD, and RT decreased significantly (p < 0.01) while the DCP VD increased (p = 0.029). The BCVA improved significantly (p < 0.001) and was associated with the MS (rs = -0.377, p = 0.015). MS was associated with the SCP VD and RT at 3M (SCP VD rs = 0.511, p = 0.001; RT rs = 0.456, p = 0.003). In the superior quadrant, the MS improved significantly (p < 0.001) and the improvement of MS was associated with the reduction of VT (β = -0.330, p = 0.034). Conclusion: Microcirculatory remodeling and perfusion recovery were observed within 3months after iERM surgery. VT was a novel index for evaluating the morphology of the retinal microvasculature in eyes with iERM and was associated with MS in the superior quadrant.

Continuous Glucose Monitoring-Derived Metrics and Capillary Vessel Density in Subjects with Type 1 Diabetes without Diabetic Retinopathy.

Optical coherence tomography angiography (OCTA) is an innovative and reliable technique detecting the early preclinical retinal vascular change in patients with diabetes. We have designed our study to evaluate whether an independent relationship exists between continuous glucose monitoring (CGM)-derived glucose metrics and OCTA parameters in young adult patients with type 1 diabetes without diabetic retinopathy (DR). Inclusion criteria were age ≥ 18 years, diagnosis of type 1 diabetes from ≥ 1 year, stable insulin treatment in the last three months, use of real-time CGM, and CGM wear time ≥ 70%. Each patient underwent dilated slit lamp fundus biomicroscopy to exclude the presence of DR. A skilled operator performed OCTA scans in the morning to avoid possible diurnal variation. CGM-derived glucose metrics from the last 2 weeks were collected through the dedicated software during OCTA. Forty-nine patients with type 1 diabetes (age 29 [18; 39] years, HbA1c 7.7 ± 1.0%) and 34 control subjects participated in the study. Vessel density (VD) of the whole image and parafoveal retina in the superficial (SCP) and deep capillary plexus (DCP) was significantly lower in patients with type 1 diabetes compared to controls. The coefficient of variation of average daily glucose, evaluated by CGM, significantly correlated with foveal and parafoveal VD in SCP and with foveal VD in DCP. High glucose variability might be responsible for the early increase of VD in these areas. Prospective studies may help understand if this pattern precedes DR. The difference we detected between patients with and without diabetes confirms that OCTA is a reliable tool for detecting early retinal abnormalities.

Evaluation of the Vascular Density, the Area of Foveal Avascular Zone, and Corrected Vision in Patients with Diabetic Macular Edema after Anti-VEGF Therapy

Background and Objective: This study aimed to evaluate the changes in macular superficial and deep capillary plexus (SCP and DCP) density, Foveal Avascular Zone (FAZ) area, and visual acuity in patients with diabetic macular edema after anti-VEGF therapy. Materials and Methods: This descriptive-analytical study utilized before and after treatment design. In total, 30 eyes of 30 patients with diabetic macular edema were investigated in this study. Optical Coherence Tomography Angiography (OCTA) images were taken at baseline (before injections) and at visits after injections (30 days after injections). The patients were treated with intravitreal injection of Avastin (Bevacizumab) with a dose of 2.5 mg per month. Macular vessel density of the SCP and DCP, as well as FAZ area were measured in each OCTA. Best corrected visual acuity (BCVA) was measured at baseline visit and at last visit (30 days after the third injection). Results: The mean age of patients was 57.33 years. Vessel density in SCP, DCP, and FAZ area were found to be significantly different before and after one, two, or three intravitreal injections (P&lt;0.001). However, vessel density was not found to be significantly different in SCP, DCP, and FAZ area among one, two, or three intravitreal injections (P&gt;0.05). Moreover, BCVA was not significantly different before and after intravitreal injections (P&gt;0.05). Conclusion: In this study, macular vessel density and FAZ area statistically changed following the intravitreal injections of Bevacizumab; however, they were unchanged among three injections. In addition, the BCVA remained unchanged before and after treatment. Anti-VEGF effect on macular perfusion may cause a direct change in the micro vascular flow.

Long-Term Macular Vascular Changes after Primary Rhegmatogenous Retinal Detachment Surgery Resolved with Different Tamponade or Different Surgical Techniques.

Simple SummaryPrimary rhegmatogenous retinal detachment is an acute threat to visual impairment due to a retinal break that allows the passage of vitreous fluid into the subretinal space. Although it is clear that functional results are influenced by retinal detachment extension and surgical timing, we do not have definitive indications on post-operative changes in macular microcirculation and how they might affect visual performance. The study aims to evaluate the long-term macular vascular changes and their correlation with functional recovery in patients successfully treated for rhegmatogenous retinal detachment. We found a reduction of the vascular density in the operated eyes, not influenced by surgical techniques, independently from the pre-operative detachment extension. However, we found that functional recovery is influenced by different intraoperative choices. In conclusion, such visual acuity and microvascular changes can be considered biomarkers that highlight the relevance of careful management of this sight-threatening disease.Background: The aim of this study was to assess long-term macular vascular changes and their correlation with functional recovery in patients successfully treated for Macula-ON and Macula-OFF rhegmatogenous retinal detachment (RRD). Methods: This retrospective observational study included 82 eyes of 82 patients who received primary successful retinal detachment surgery, 33 Macula-ON and 49 Macula-OFF. Superficial and deep capillary plexuses (SCP and DCP) were evaluated by optical coherence tomography angiography (OCTA), and were correlated with visual acuity (VA), surgical technique and tamponade at 12 months after surgery. The fellow eyes were used as controls. Results: At 12-month follow-up, there was a significant decrease in the vessel density (VD) in the SCP in the operated eyes compared to control eyes (p < 0.05) in both the Macula-ON and Macula-OFF groups. Vessel length density (VLD) decrease in SCP was more extended in the Macula-OFF group. No difference in the DCP perfusion parameters was found, compared to controls. Subgroup analysis dependent on the type of surgery or tamponade showed no significant differences of VD and VLD. An inverse correlation was found between the SCP VD and the duration of silicone oil (SO) tamponade (p = 0.039). A significant correlation was observed between parafoveal SCP VD and final best corrected visual acuity (BCVA) (p = 0.028). The multivariate linear regression analysis showed that only the type of tamponade was significantly correlated with the final BCVA in the Macula-ON group (p = 0.004). Conclusions: Our study described long-term perfusion changes in RRD after surgery, with lower SCP VD and VLD in the operated eyes compared to the fellow ones, not influenced by type of surgery or tamponade. The choice of tamponade and SO removal timing may affect functional outcomes, especially in Macula-ON RRD. In conclusion, such functional and perfusion changes can be considered biomarkers that highlight the relevance of careful management of this sight-threatening disease.

Microvascular assessment of macula, choroid, and optic disk in children with unilateral amblyopia using OCT angiography.

To investigate the microvascular changes of macula, choroid, and optic disk in children with unilateral amblyopia. This prospective cross-sectional study involved 39 unilateral amblyopic children and 39 age- and sex-matched heathy participants who served as control. Vessel densities of the superficial and deep capillary plexuses (SCP and DCP), foveal avascular zone (FAZ) area, macular thickness, optic disk vessel density, retinal nerve fiber layer (RNFL) thickness, choriocapillaris vessel density, and subfoveal choroidal thickness were evaluated by OCT angiography (OCTA). Meanwhile, the correlations of microvascular perfusion and structural changes of macula, choroid, and optic disk were analyzed. The vessel density of SCP and DCP in the whole macula in the amblyopic group was significantly lower than that in the control group after adjusting for age, axial length, and spherical equivalents (all P < 0.05). FAZ area, macular thickness, RNFL thickness, and the optic disk vessel density were not statistically different between the amblyopic group and the control group (all P > 0.05). Subfoveal choroidal thickness of amblyopic eyes was significantly higher than that of control eyes(P = 0.032). Choriocapillaris flow void (FV) in the amblyopic group was greater than that in the control group (P = 0.013). Significant differences were observed between the fellow eyes and the control eyes in choriocapillaris FV and subfoveal choroidal thickness (P = 0.011 and P = 0.042, respectively). Foveal SCP and DCP vessel density in all studied eyes were positively correlated with the whole macular thickness, respectively (r = 0.556 and r = 0.627, respectively, both P < 0.001). Whole SCP and DCP vessel density in the amblyopic eyes were negatively correlated with choriocapillaris FV (r = -0.723, P < 0.001; r = -0.512, P = 0.001, respectively). Children with amblyopic eyes have attenuated macular and choriocapillaris perfusion. There is a need for future studies that will investigate the pathophysiology of amblyopia in children by OCTA.

Quantitative OCT Angiography Assessment of the Effect of Peribulbar Anesthesia on Retinal Microvasculature in Primary Open-Angle Glaucoma Patients Undergoing Cataract Surgery.

ObjectiveTo assess the effect of peribulbar anesthesia on retinal microvasculature in primary open-angle glaucoma (POAG) patients undergoing cataract surgery using OCT Angiography.ParticipantsForty-nine patients undergoing cataract surgery were divided into two groups. Group I included patients with no history of glaucoma, while group II included patients previously diagnosed as POAG with controlled IOP. Each participant received 6 mL of peribulbar anesthetic injection of 4 mL lidocaine 2% containing 150 IU hyaluronidase and 2 mL bupivacaine 0.5%. They were scanned with the OCT-A 10 minutes before and 10 minutes after injection for foveal deep (DCP), superficial (SCP) capillary plexuses density and total vessel density, foveal avascular zone (FAZ) diameter, optic disc total vessel density, and radial peripapillary capillary (RPC) network density. In addition, IOP was checked before and 10 minutes after injection.ResultsMedian percent change in DCP post-injection was significantly greater in group II (−43%) than in group I (−2.5%) (P < 0.001). Also, DCP total density median percent change post-injection was significantly higher in group II (−21%) than in group I (−0.9%) (P < 0.001). Foveal SCP vessel density and total vessel density median percent change post-injection were −62.6% and −16.2%, respectively, in group II and were −2.6% and −1.1%, respectively, in group I, which are statistically significant (P < 0.001). The FAZ diameter median percentage change post-injection was higher in group II (40.6%) than in group I (2.5%) (P < 0.001). Optic disc total vessel density and radial peripapillary capillary (RPC) network density post-injection median percent change were significantly higher in group II (−13.6%) and (−13.1%) respectively than in group I (−1.1%) and (−1.25%) respectively (P < 0.001).ConclusionPeribulbar anesthesia harbors a deleterious ischemic effect on the retinal vascular tree of glaucoma patients, which could harmfully affect the vision and the visual field in those vulnerable patients.

Analysis of microvascular and neurodegenerative complications of mild COVID-19

PurposeTo examine retinal and corneal neurodegenerative and retinal microvascular changes in patients after mild or asymptomatic COVID-19 disease compared to age-matched controls.MethodsThirty-five (35) patients after PCR-proven SARS-CoV-2 infection and 28 age-matched controls were enrolled. Swept-source optical coherence tomography (OCT), OCT angiography, and in vivo corneal confocal microscopy were performed in both groups. Corneal subbasal nerve plexus was quantified. Vessel density for superficial (SCP) and deep capillary plexus (DCP) and structural OCT parameters were recorded.ResultsSignificantly lower nerve branch density (P = 0.0004), nerve fiber area (P = 0.0001), nerve fiber density (P = 0.0009), nerve fiber length (P < 0.0001), and total nerve branch density (P = 0.002) values were observed in patients after COVID-19 compared to healthy controls. VD of the temporal SCP was significantly different between the two groups (P = 0.019). No other SCP and DCP vessel density parameter differed significantly between the two groups.ConclusionsOur results suggest that peripheral neurodegenerative changes may occur even after mild or asymptomatic SARS-CoV-2 infection. No relevant microvascular changes were seen with OCT angiography and structural OCT parameters did not show any signs of optic neuropathy in post-COVID patients. In vivo confocal microscopy seems to be an important tool in monitoring peripheral neuropathy in patients after COVID-19.

Study of Retinal and Choroidal Changes in Children with Sickle Cell Disease using Optical Coherence Tomography and Angiography

Abstract Background Sickle cell disease is known to cause vaso-occlusive peripheral retinopathy as a result of the microvascular insults that occur when sickled erythrocytes affect the retinal and choroidal blood flow. This leads to non-proliferative retinopathy (NPR) and proliferative retinopathy (PR) that can result in vision affection. While sickle cell retinopathy (SCR) in adult patients is well described, less is known about the retinal changes that occur in pediatric patients. To date, most studies have been of adults. Objective To screen children with sickle cell disease for the presence of retinal and choroidal changes and to compare the findings with age and sex matched controls by performing structural SD-OCT and OCTA and to correlate between findings. This aimed to assess the prevalence and age of onset of retinopathy among pediatric patients. Patients and Methods This cross sectional study was carried out from February 2020 to August 2020 on 30 eyes of patients attending outpatient clinic of Ophthalmology and Pediatric Departments of Ain Shams University Hospitals. Those patients were asked to participate and were enrolled in this study. The ethical standards stated by the ethical committee of Ain Shams University Hospitals were followed. Informed written consent was taken from guardians of all participants. Results There was a significant difference between the cases and control groups regarding the SCP and DCP vessel density, FAZ area, vascular disc density, central macular thickness, choroidal thickness, RNFL average thickness, IS/OS and C/D vertical ratio. However, there was no significant difference between the cases two groups regarding the GCC. There was a significant positive correlation between the retinal thickness and the vessel density in the SCP and DCP in the corresponding subfields. There was a positive statistically significant correlation between the Hb F level and the vessel density of the SCP and DCP. Also, there was a negative statistically significant correlation between the Hb F level and the FAZ. There was a negative statistically significant correlation between the Hb S level and the choroidal thickness, GCC and RNFL average thickness. There was also a statistically significant negative correlation between the disease duration and the temporal parafoveal retinal thickness. Conclusion SD-OCT and OCTA were able to detect areas of thinning and decreased vascular densities in asymptomatic sickle cell children. This study demonstrated a decreased vessel density on OCTA but a normal retinal thickness on SD-OCT in some of the parafoveal sucfields. This suggests that OCTA can detect microvascular abnormalities and retinopathy early even before it is visible on OCT. Further longitudinal studies are needed to examine the vascular densities and retinal and choroidal thinning in sickle cell disease children and their correlation with the various disease parameters.

Age and signal strength-related changes in vessel density in the choroid and the retina: an OCT angiography study of the macula and optic disc.

To investigate the effects of ageing and signal strength index (SSI) on vessel density (VD) measurements of the radial peripapillary capillaries (RPC) in the optic disc, the retinal superficial (SCP) and deep (DCP) capillary plexi and the choriocapillaris (CC) of the macular area using optical coherence tomography angiography (OCT-A) imaging. This cross-sectional study included 138 eyes from 77 healthy participants. High-definition (HD) disc Angio scan (4.5X4.5 mm) and HD Angio retina scan (6X6 mm) were acquired. Whole image (WI) VDs, inside disc (ID) VD and global and hemifield peripapillary RPC VDs were evaluated from the Angio Disc scans. Global and hemifield VD for the SCP, DCP and CC slab in the macula area were also recorded across different age groups. Mean age was 48.2 ± 15.0 years (range 25-82 years). Signal strength index (SSI) was 71.6 ± 7.6 in the macula and 74.6 ± 9.2 in the disc OCT-A image. VD for both SCP and DCP decreased by 0.084% and 0.188%/year (both p < 0.001). WI VD and ID VD also decreased by 0.037%/year (p = 0.005) and 0.092%/year (p < 0.001). Peripapillary RPC VD did not change with age or SSI. The effect of SSI was significant in SCP, DCP, WI RPC, ID RPC and CC VD. In the generalized estimating equationmodel testing for both SSI and age, SSI remained significant against SCP, DCP and ID RPC. With ageing, a decrease in VD in the SCP, DCP, WI and ID RPC, as well as in SSI, is seen. SSI and age are associated with VD changes, but only SSI is the significant variable that explains the variation in the retina microvasculature in the macula and the optic disc in multivariate analysis. In the CC, a larger SSI was associated with a lower VD. These findings underscore the importance of controlling for SSI in future studies using OCT-A.

Evaluation of macular perfusion in patients with treatment-naive overt hypothyroidism using optical coherence tomography angiography

Background/Aim: Thyroid hormones play an essential role in retinal development and physiological functions. Although the effects of hyperthyroidism on ocular circulation are well-defined, no studies report the effects of clinical hypothyroidism on retinal and choroidal circulation. We aimed to compare the macular vessel density and flow indexes of patients with treatment-naive hypothyroidism and healthy controls using optical coherence tomography angiography (OCTA). Methods: This case-control study included 104 eyes of 52 participants. Group 1 (n=24) consisted of patients with treatment-naive overt hypothyroidism, while Group 2 (n=28) consisted of age and sex-matched healthy controls. Images were obtained using AngioVue software 2.0 of the OCTA device in a 6 × 6 mm area centered on the macula. Foveal avascular zone (FAZ) area, macular retinal thickness, FAZ perimeter (PERIM), choroidal flow index (CF), outer retinal flow index (ORF) and macular vessel density (VD) in the superficial (SCP) and deep retinal capillary plexus (DCP) were recorded for all patients. Results: The whole [Group 1: 49.9 (7.0)%; Group 2: 54.6 (5.9)%], parafoveal [Group 1: 54.7 (4.8)%; Group 2: 58.6 (3.9)%] and perifoveal [Group 1: 51.5 (7.2)%; Group 2: 55.9 (6.8)% ] VD in DCP were significantly lower in Group 1 compared to Group 2 (P=0.012; P=0.002 and P=0.028 respectively). However, parafoveal VD in SCP was significantly higher in Group 1 [52.4 (2.26)] than in Group 2 [49.9 (6.87)] (P=0.032). The mean VD in DCP was significantly positively correlated with the choroidal (P=0.021) and outer retinal flow indexes (P=0.033). The mean foveal VD in DCP was significantly positively correlated with the mean foveal (P<0.001), parafoveal (P=0.001) and perifoveal retinal thicknesses (P<0.001). Conclusion: Our study has provided, for the first time, a quantitative assessment of macular perfusion in patients with overt hypothyroidism using OCTA. The reduction in VD in the DCP might be attributed to the lack of angiogenic effects of T4 or neural hypometabolism secondary to hypothyroidism.

Retinochoroidal vascular plexuses in patients with iron deficiency anaemia

ABSTRACT Clinical relevance Optical coherence tomography angiography (OCT-A) may enable the identification of alteration in the retinochoroidal microvasculature in patients with iron deficiency anaemia. Background To investigate the presence of macular microvascular alterations in females with IDA by using OCT-A. Methods This is a cross-sectional comparative study. Forty patients with IDA and 35 age-matched healthy women underwent a complete ophthalmologic examination and OCT-A imaging. Foveal avascular zone parameters and the vessel density in the superficial (SCP) and deep capillary plexus (DCP) were calculated using automated software. All measurements were compared between groups. Correlations between the OCT-A metrics and haematological laboratory parameters were evaluated. Results Compared to healthy subjects, IDA patients revealed significantly decreased vessel density of the SCP in all parafoveal quadrants (p < 0.05). In contrast, vessel density analysis in DCP has shown no statistically significant difference in all parafoveal quadrants (p > 0.05). Although foveal vessel density in both SCP and DCP were higher in the IDA group, only the foveal vessel density in DCP was significantly higher than controls (p = 0.001). The mean values of the foveal avascular zone area and perimeter and choriocapillaris flow area were significantly lower in the IDA group (p < 0.05). The parafoveal vessel density in SCP, foveal avascular zone area, and choriocapillaris flow area were positively correlated with haematological parameters including haemoglobin, haematocrit, mean corpuscular haemoglobin, and mean corpuscular volume (p < 0.01). Conclusion Patients with IDA had decreased parafoveal vessel density in the SCP, but not the DCP. Foveal avascular zone metrics and choriocapillaris flow area measurements were significantly lower in IDA.

Vessel Density Changes on Optical Coherence Tomography Angiography after Vascular Endothelial Growth Factor Inhibitor Treatment for Diabetic Macular Edema.

Objectives:To evaluate the changes in macular vessel density after treatment with vascular endothelial growth factor (VEGF) inhibitors in center-involving diabetic macular edema (DME) and to compare these changes between anatomical responders and non-responders.Materials and Methods:This retrospective study included 22 eyes with center-involving DME. All eyes had 3 consecutive administrations of VEGF inhibitors. Optical coherence tomography (OCT) and OCT angiography (OCTA) of the macula with manual adjustment of segmentation lines were performed at baseline and after treatment. Vessel density in the central and parafoveal regions of the superficial and deep capillary plexus (SCP/DCP) were measured at baseline and after treatment. Vessel density and changes therein were compared between anatomical responders and non-responders as defined by changes in central subfield thickness (CST).Results:Overall, there were no significant differences in vessel density in the central and parafoveal regions of the SCP and DCP after treatment compared to baseline. After categorization by anatomical response, 12 eyes were responders (CST decreased by 173.7±47.7 μm) and 10 eyes were non-responders (CST increased by 20.8±38.9 μm) (p<0.0001). There were no corresponding significant differences between responders and non-responders in SCP and DCP vessel density or changes therein after treatment.Conclusion:There were no significant changes in macular vessel density after the early stages of VEGF inhibitor treatment for DME, and there was no relationship with the anatomical response. The effect of VEGF inhibitors in DME treatment may not be related to increasing vessel density.

Retinal microvasculature dysfunction is associated with Alzheimer\u2019s disease and mild cognitive impairment

sBackgroundThe retina and brain share many neuronal and vasculature characteristics. We investigated the retinal microvasculature in Alzheimer’s disease (AD) and mild cognitive impairment (MCI) using optical coherence tomography angiography (OCTA).MethodsIn this cross-sectional study, 24 AD participants, 37 MCI participants, and 29 controls were diagnosed according to internationally accepted criteria. OCTA images of the superficial and deep capillary plexus (SCP, DCP) of the retinal microvasculature were obtained using a commercial OCTA system (Zeiss Cirrus HD-5000 with AngioPlex, Carl Zeiss Meditec, Dublin, CA). The main outcome measures were vessel density (VD) and fractal dimension (FD) in the SCP and DCP within a 2.5-mm ring around the fovea which were compared between groups. Perfusion density of large vessels and foveal avascular zone (FAZ) area were additional outcome parameters.ResultsAge, gender, and race did not differ among groups. However, there was a significant difference in diabetes status (P = 0.039) and systolic blood pressure (P = 0.008) among the groups. After adjusting for confounders, AD participants showed significantly decreased VD in SCP and DCP (P = 0.006 and P = 0.015, respectively) and decreased FD in SCP (P = 0.006), compared to controls. MCI participants showed significantly decreased VD and FD only in SCP (P = 0.006 and P < 0.001, respectively) and not the DCP (P > 0.05) compared with controls. There was no difference in the OCTA variables between AD and MCI (P > 0.05). Perfusion density of large vessels and FAZ area did not differ significantly between groups (P > 0.05).Conclusions and relevanceEyes of patients with AD have significantly reduced macular VD in both plexuses whereas MCI participants only showed reduction in the superficial plexus. Changes in the retinal microvasculature and capillary network may offer a valuable insight on the brain in AD.

Association of OCT Angiography Parameters With Age in Cognitively Healthy Older Adults.

To evaluate the association of changes in retinal anatomy and microvasculature with age and sex in cognitively healthy older adults. Cross-sectional study of cognitively healthy subjects aged 50 years and older who underwent optical coherence tomography angiography (OCTA) to estimate the association between age and sex with ganglion cell layer-inner plexiform layer (GC-IPL); central subfield thickness (CST); subfoveal choroidal thickness (CT); foveal avascular zone (FAZ) size; and superficial (SCP), deep (DCP), and whole capillary plexus (WCP) vessel density (VD) and perfusion density (PD) measured in the ETDRS 3-mm and 6-mm circle and rings. Among 141 older adults (72.9% female; median age: 69 years), 282 eyes were imaged. Females had a greater CT, GC-IPL thickness, and FAZ size and a lower CST than males. After controlling for sex, both CT (P = .001) and GC-IPL thickness (P < .001) decreased with age, whereas FAZ size and CST did not. There was a reduction in VD and PD in SCP, DCP, and WCP with age in the 3-mm circle, 3-mm ring, and 6-mm circle (all P < .05). There is a significant reduction in both VD and PD, as well as decreased choroidal and GC-IPL thickness associated with aging, even beyond the fifth decade, in cognitively healthy adults. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:706-714.].

Associations between Macular OCT Angiography and Nonproliferative Diabetic Retinopathy in Young Patients with Type 1 Diabetes Mellitus.

Methods OCTA of both eyes was performed in a cross-sectional study of 14 to 30-year-old individuals with at least 10-year duration of T1D and controls recruited from the Norwegian Atherosclerosis and Childhood Diabetes (ACD) study. Vessel density (VD) and foveal avascular zone (FAZ) area in the superficial and deep capillary plexus (SCP and DCP), total retinal volume (TRV), and central macular thickness (CMT) were calculated using automated software. Univariate and multivariate ordered logistic regression (OLR) models were used accordingly. Results We included 168 control eyes and 315 T1D eyes. Lower VD in DCP (OR 0.65, 95% CI 0.51–0.83), longer diabetes duration (OR 1.51, 95% CI 1.22–1.87), and higher waist circumference (OR 1.08, 95% CI 1.02–1.14) were significantly associated with progression of NPDR. VD in SCP and DCP were significantly lower in T1D patients without diabetic retinopathy than in controls. Conclusions Sparser VD in DCP is significantly associated with severity of NPDR, supporting that OCTA might detect the earliest signs of NPDR before it is visible by ophthalmoscopy.