Anatomical changes in idiopathic epiretinal membrane at 2-year follow-up assessed using spectral domain optical coherence tomography and optical coherence tomographic angiography

PURPOSE

To evaluate anatomical changes in the low-stage partial attachment-type idiopathic epiretinal membrane (iERM) over 2 years.

METHODS

Data from patients with low-stage partial attachment-type iERM (stage 2) were analyzed. The main outcome measures were anatomical changes, including changes in the foveal avascular zone (FAZ) area, vessel density (VD) in the vascular plexus, and thickness of retinal sublayers during the follow-up period.

RESULTS

Thirty patients (mean age: 68±12 years) were included in the study. The FAZ area on the superficial vascular plexus (SVP) significantly decreased from baseline (0.12±0.08 mm2) to month 24 (0.10±0.08 mm2, p=0.024). However, the FAZ area on the deep vascular plexus (DVP) did not significantly decrease from baseline (0.15±0.13 mm2) to month 24 (0.14±0.14 mm2, p=0.099). VDs on both the SVP and DVP did not show significant change from baseline (29.51±8.14% vs. 28.35±5.63%) to month 24 (29.79±9.77%, p=0.564 vs. 28.17±5.75%, p=0.417). Parafoveal ganglion cell and inner plexiform layer (GCIPL) thickness decreased from baseline (108.77±13.61 μm) to month 24 (103.03±15.54 μm, p=0.004). The central total retinal layer thickness did not significantly change from baseline (396.07±64.86 μm) to month 24 (392.04±72.72 μm, p=0.570).

CONCLUSION

Even in low-stage ERM, inner retinal changes, including GCIPL thickness, occurred during follow-up periods, which might be owing to degenerative changes or centrifugal movement.

Comparison of macular and optic disc vessel density in thyroid orbitopathy: a comparative octa study

PURPOSE

To determine the microvascular and structural changes in the peripapillary and macular areas observed in patients with active thyroid orbitopathy(TO) before and after steroid treatment and compare with inactive TO and the control group by optical coherence tomography angiography (OCTA).

MATERIAL AND METHOD

This cross-sectional study included 34 eyes of 17 active TO patients, 108 eyes of 54 inactive TO patients, and 60 eyes of 30 healthy controls. Central macular thickness (CMT), ganglion cell layer-inner plexiform layer (GCL-IPL) thickness, central choroidal thickness (CCT), retinal nerve fiber layer (RNFL) thickness, choroidal thickness in the peripapillary region, superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris vessel densities were determined by OCTA in before and after 12-week steroid treatment of active TO cases, inactive TO and control groups.

RESULTS

Between the three groups in macula OCTA, a statistically significant difference was observed in the inferior and nasal quadrants in SCP (all p = 0.01) and only in the temporal quadrant choriocapillaris (p = 0.005). In peripapillary OCTA, a statistically significant difference was found only in the central choriocapillaris (p = 0.03). In the comparison of the active group before and after treatment, there was a statistically significant decrease in CMT and CCT; a statistically significant increase was observed in GCL-IPL (all p < 0.01). There was a statistically significant decrease in SCP and DCP only in the central (all p < 0.01). There was a statistically significant increase was found in the lower quadrant macular SCP vessel density and mean macular DCP in post-treatment measurements (p = 0.01 and p = 0.03, respectively). Peripapillary SCP and DCP vessel density was increased after treatment (p < 0.01).

CONCLUSION

Active TO group had lower vessel density than inactive group and after treatment, vessel density was increased. Non-invasive quantitative analysis of retinal and optic disc perfusion using OCTA could be useful in early treatment before complications occur and monitoring patients with TO.

Changes in retinal vascular density measured by optical coherence tomography angiography in patients with carotid artery stenosis after carotid artery stenting and angioplasty

PURPOSE

The aim of this study was to compare the effect of carotid artery stenting and angioplasty (CASA) on retinal vascular density (VD) in patients with severe carotid stenosis with a healthy control group and to evaluate using optical coherence tomography angiography (OCTA).

METHODS

For this prospective study, eyes on the operated side constituted the ipsilateral eye group, and the other eye constituted the contralateral eye group. 40 eyes of 40 patients with ipsilateral eye of carotisid artery stenosis (CAS), 34 eyes on contralateral side, and 30 healthy eyes (control group) were included in this study. We performed quantitative OCTA analyses of retinal VD changes, before and after CASA. The main outcome measures were the quantitative changes of VD of superficial capillary plexus (SCP) and deep capillary plexus (DCP).

RESULTS

We evaluated the VD of ipsilateral eyes and contralateral eyes separately before and after the procedure. All patients did not have visual symptoms. There was no significant difference in the VD of SCP in all groups before the procedure. No significant change was observed in all groups when the VD of the SCP was compared before and after the procedure. The VD of the DCP in the ipsilateral and contralateral group improved significantly after CASA.

CONCLUSION

OCTA could noninvasively detect retinal VD improvements after CASA in CAS patients. Quantitative changes in VD evaluated using OCTA are thought to be early indicators in the diagnosis of CAS and in the follow-up of treatment success.

Comparison of retinochoroidal and optic nerve head microvascular circulation between HIV-positive patients and healthy subjects using optical coherence tomography angiography

PURPOSE

To evaluate the retinal, choroidal, and optic disc head microvascular circulation in human immunodeficiency virus (HIV)-infected individuals without retinopathy receiving highly active antiretroviral therapy (HAART) using swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

This cross-sectional study included 100 eyes of 100 patients with HIV infection but no HIV-related ocular disease and 108 eyes of 108 age- and sex-matched healthy subjects as the control group. SS-OCTA was used to assess foveal avascular zone (FAZ) area, retinal nerve fiber layer thickness (RNFL), choriocapillaris (CC) flow area, outer retinal (OR) thickness, radial peripapillary capillary (RPC) vessel density (VD), ONH VD, and choroidal thickness.

RESULTS

No statistically significant difference was found between the two groups except in the foveal VD of the deep capillary plexus (DCP). The foveal VD of the DCP was lower in the HIV-positive group (P=0.011). The mean FAZ area (mm2), perimeter (mm), and CC flow area (mm) values were higher in the HIV-positive group at statistically significant levels (P=0.021, P=0.02, and P=0.039, respectively). However, no statistically significant differences were found between the two groups concerning the OR flow area, subfoveal choroidal thickness, or the VDs of the RPC or ONH.

CONCLUSIONS

This is the first study in the literature to evaluate the microvascular circulation of the ONH in HIV-positive patients. Although retinal and choroidal microvascular circulation decreased in HIV-positive patients receiving HAART treatment, we found no effect on the microvascular circulation of the ONH or RPC microvascular circulation. Our findings suggest that retinochoroidal microvascular circulation is affected in HIV-positive patients over time.

Investigation of the effects of gestational diabetes and hypertension on retinal and choroidal microvascular circulation using swept-source optical coherence tomography angiography

PURPOSE

The aim of this study was to investigate the microvascular changes in the retina and choroid in gestational diabetes mellitus (GDM) and pregnancy-induced hypertension (PIH) and to compare the results with those of healthy pregnant subjects.

METHODS

Twenty-nine pregnant subjects with coexisting GDM and PIH (group 1) and 36 healthy pregnant subjects (group 2) were enrolled in the study. All subjects were examined by optical coherence tomography (OCT) and angiography (OCTA). The retina, retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), choroidal thickness (CT), superficial capillary plexus (SCP), deep capillary plexus (DCP), choriocapillaris (CC) vascular density (VD), and foveal avascular zone (FAZ) were measured.

RESULTS

We observed that the values of CT and VD were lower in group 1 than in group 2. No significant difference was found between groups in RT, FAZ area and CC VD. SCP and DCP VD values were higher in group 2 in all quadrants. We observed a significant increase in FAZ area and CC VD with increasing systolic blood pressure. No correlation was observed between diastolic blood pressure and FBS with other parameters. In group 1, FAZ area was significantly higher in the diet-treated group than in the insulin-treated group.

CONCLUSION

Monitoring and treatment of pregnant women with PIH and GDM is important because of the risks that may occur during pregnancy. We believe that changes in microvascular circulation can be detected noninvasively with OCTA, even in the absence of clinical or retinal findings.

Eye signs as a novel risk predictor in pulmonary arterial hypertension associated with systemic lupus erythematosus

OBJECTIVE

To investigate the role of eye signs in predicting poor outcomes in systemic lupus erythematosus (SLE) patients with pulmonary arterial hypertension (PAH).

METHODS

This prospective observational study recruited patients diagnosed with SLE-PAH from Jan. 2021 to Dec. 2021 at the First Affiliated Hospital of Nanchang University; those with other potential causes of PAH were excluded. The evaluation of various parameters, such as N-terminal prohormone of brain natriuretic peptide (NT-proBNP), 6-minute walking distance (6MWD), World Health Organization functional class (WHO-FC), echocardiography, and risk stratification based on the 2015 European Society of Cardiology (ESC)/European Respiratory Society (ERS) Guidelines, was conducted at intervals of every 1-3 months, and a 6-month follow-up period was observed. The primary outcome measure considered improvement if there was a decline in the risk stratification grade at the end point and unimproved if there was no decline. Conjunctival microvascular images were observed and recorded.

RESULTS

A total of 29 SLE-PAH patients were enrolled, comprising 12 in the improved group and 17 in the nonimproved group. All SLE-PAH patients showed various manifestations of eye signs, including vessel twisting, dilation, ischaemic areas, haemorrhages, reticulum deformity, and wound spots. The nonimproved group exhibited significantly lower vessel density (VD) and microvascular flow index (MFI) of conjunctival microvascular images than the improved group. Correlation analysis revealed that VD displayed a negative correlation with the WHO-FC (r = -0.413, p = 0.026) and NT-proBNP (r = -0.472, p = 0.010), as well as a positive correlation with the 6MWD (r = 0.561, p = 0.002). Similarly, MFI exhibited a negative correlation with WHO-FC (r = -0.408, p = 0.028) and NT-proBNP (r = -0.472, p = 0.010) and a positive correlation with 6MWD (r = 0.157, p = 0.004). Multivariate logistic regression analysis indicated that VD (OR 10.11, 95% CI 1.95-52.36), MFI (OR 7.85, 95% CI 1.73-35.67), NT-proBNP, and 6MWD were influential factors in predicting the prognostic improvement of SLE-PAH patients. ROC curve analysis demonstrated that VD, MFI, 6MWD, and NT-proBNP (with respective AUC values of 0.83, 0.83, 0.76, and 0.90, respectively) possessed a sensitivity and specificity of 75 and 100%, as well as 83 and 100%, respectively. Regarding prognostic prediction, VD and MFI exhibited higher sensitivity than 6MWD, whereas MFI displayed higher sensitivity and specificity than NT-proBNP.

CONCLUSION

SLE-PAH can lead to various conjunctival microvascular manifestations in which vascular density and microvascular flow index can be used to assess cardiopulmonary function and predict therapeutic efficacy and prognosis in SLE-PAH patients.

Chronic Central Serous Chorioretinopathy in Elderly Subjects: Structure and Blood Flow Characteristics of Retina and Choroid

INTRODUCTION

With advancements in imaging technology, researchers have been able to identify more distinctive imaging features of central serous chorioretinopathy (CSC). However, existing research primarily concentrates on young patients aged 50 years and below, leaving a dearth of studies on elderly CSC patients. Previous studies indicate that elderly CSC patients may exhibit unique imaging characteristics and have a clinical prognosis that significantly differs from younger patients. This study aimed to evaluate the characteristics of retina, choroid structure, and blood flow in elderly patients with chronic CSC (cCSC) examined multimode imaging and try to find new pathogenesis information of it.

METHODS

Using a cut-off age of 50 years, patients with chronic central serous chorioretinopathy were divided into two groups: older and younger. The control group consisted of 40 healthy individuals, with their right eyes assigned. Various clinical features were recorded, including the incidence of ellipsoid zone rupture (EZ-), fibrin in the subretinal fluid (SRF), pachydrusen, subretinal drusenoid deposits (SDD), pigment epithelial detachment (PED), double-layer sign (DLS), and choroidal lipid globule cavern. Measurements were taken for the thickness of the outer nuclear layer (ONL), the length of the extended outer photoreceptor segment (POS), the height and width of SRF, the vascular density of each layer of the retinal capillary plexus, the central macular thickness (CMT), and the subfoveal choroidal thickness (SFCT).

RESULTS

The proportion of females in the elderly group (43.75%) was significantly higher than that in the youth group (22.41%) (p = 0.034). The degree of hyperopia in the elderly group (1.03 ± 0.73) was higher than that in the youth group (0.26 ± 1.06), with a significant difference in BCVA (p = 0.05). The thickness of SFCT, CMT, ONL in the elderly group, and the length of photoreceptor outer segment in the elderly group were thinner than those in the youth group (p < 0.05). Choroidal capillary perfusion area (CCPA), macular area, and paramacular area were lower in the elderly group than those in the youth group in the full scan range (p < 0.05). The blood flow densities of deep capillary plexus (DCP), intermediate capillary plexus (ICP), and superficial capillary plexus (SCP) in the whole scan range, macular area, and paramacular area were lower in the elderly group than in the youth group, but the differences were not statistically significant.

CONCLUSIONS

In conclusion, our data suggest that elderly patients with cCSC may experience different disease outcomes. Elderly cCSC patients exhibit less gender bias, poorer vision, more severe structural damage and ischemia in the choroid and retina, and have a higher risk of developing choroidal neovascularization.

Assessment of early macular microangiopathy in subjects with prediabetes using optical coherence tomography angiography and fundus photography

AIMS

Early detection of retinal microangiopathy in patients with prediabetes may reduce diabetic retinopathy complications. The aim of this study was to assess early macular vascular changes in prediabetics before development of over diabetes using OCTA and fundus photography.

METHODS

In this cross-sectional study, 66 prediabetic individuals and 66 normal controls underwent clinical, laboratory, and fundus photography evaluation followed by OCTA macular imaging to examine for the foveal avascular zone, and area of capillary non-perfusion, thickness, disorganization of vessels, and vessel density perfusion percentage of superficial capillary plexus and deep capillary plexus.

RESULTS

Retinal microangiopathy was detected in 36.4% of prediabetics by OCTA and only in 10.6% by fundus photography. None of clinical or laboratory parameters had significant association with DR. Area of capillary non-perfusion and disorganization of SCP were detected in 53.8% and 56.8%, respectively, in prediabetics. VDP of SCP and DCP of whole image, parafoveal, and perifoveal areas was significantly lower in prediabetes group compared to normal control. VDP of DCP of perifoveal area (β coefficient: - 0.10, OR: 0.91, 95% CI: 0.86-0.96, P < 0.001) and disorganization of DCP (β coefficient: 1.93, OR: 6.89, 95% CI: 2.5-18.8, P < 0.001) were significant predictors of DR in prediabetics. There was no difference in FAZ in prediabetics with and without retinopathy.

CONCLUSIONS

OCTA could detect early retinal vascular changes during the prediabetic state before developing diabetes. VDP was significantly reduced in prediabetic patients. Furthermore, VDP of DCP of perifoveal area and disorganization of DCP were the most important predictors of retinopathy in prediabetic patients.

OCT-Angiography of deep and superficial retinal vascular density changes in diabetes without diabetic retinopathy

PURPOSE

To analyze the vascular density values (VD) in the superficial and the deep retinal network and in all perimacular sectors of diabetic eyes without clinical retinopathy, comparing them to that of healthy, nondiabetic control eyes. We investigated the factors that may influence these values.

METHODS

This was a cross-sectional study including diabetics without diabetic retinopathy and healthy control subjects. All subjects underwent OCTA examination (RTVue-XR Avanti; Optovue, Fremont, CA, USA). The scanned area was 3×3mm and centered on the fovea. In the superficial and deep capillary plexus, we evaluated the total VD, parafoveal, temporal, nasal, superior and inferior sectors, as well as the superior and inferior hemi-sector VD. The sectors with the greatest area under the curve (AUC) were determined. We evaluated the correlation between certain risk factors and VD values.

RESULTS

VD values in all sectors of the superficial capillary plexus layer and deep capillary plexus layer in the diabetic group were significantly lower than in the control group. Among all the parameters, the superficial total VD and superficial parafoveal VD had the greatest AUC (0.992 and 0.991 respectively). The sector with the greatest AUC was the temporal sector in both the SCP (0.990) and DCP (0.976). Age, creatinine clearance and hyperlipemia correlated with vascular density.

CONCLUSIONS

Superficial and deep retinal VD are both decreased in diabetic patients without diabetic retinopathy. Our results suggest that OCTA might be a promising tool for diabetic retinopathy screening. Quantitative microvascular changes might precede clinical damage.

Evaluation of Posterior Ocular Blood Flow in Diabetic Retinopathy Patients Without Macular Edema Using Optical Coherence Tomography Angiography

AIM

The objective of this study is to investigate and compare the superficial and deep vascular structures of the retina, as well as the changes in the choriocapillaris (CC) and optic disc microvasculature, using optical coherence tomography angiography (OCTA) in patients diagnosed with diabetes mellitus (DM) without diabetic retinopathy (DR), patients with non-proliferative and proliferative DR, and healthy individuals.

MATERIALS AND METHODS

This prospective study conducted between July 2020 and July 2021 included patients diagnosed with type 2 DM without DR, as well as patients with mild nonproliferative, moderate nonproliferative, and proliferative DR without macular oedema. A control group of 25 age- and gender-matched healthy individuals was also included. OCTA parameters of the patients were examined.

RESULTS

In the DR groups, compared to the control group, there was a significant decrease in macular superficial, deep, and CC perfusion areas as the severity of DR increased (p<0.001). The vascular density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) exhibited a statistically significant decrease in all quadrants of the DR group compared to the control group (p = 0.033 for SCP in the fovea, p<0.001 for all other quadrants). The superficial and deep FAZs showed a significant expansion in the DR group compared to the control group (p = 0.003 for superficial FAZ, p<0.001 for deep FAZ). As the severity of DR increased, there was a statistically significant decrease in the perfusion areas of the optic nerve head (ONH), radial peripapillary capillary (RPC), and vitreous segments (p<0.001 for ONH, p = 0.031 for RPC, p<0.001 for vitreous). There was a statistically significant decrease in RPC VD in all quadrants as the severity of DR increased. Moreover, as the severity of DR increased, a statistically significant decrease in the VD of the ONH was observed in all quadrants except for the inferior nasal (p = 0.094), inferior temporal (p = 0.111), superior temporal (p = 0.18), and temporal (p = 0.284) quadrants.

CONCLUSION

Our study demonstrated the involvement of macular and optic nerve perfusion areas (PA) and VD in diabetic patients. OCTA proved to be a valuable and noninvasive imaging modality, providing an easy and repeatable assessment of posterior segment vascular changes in patients with DR.

Retinal and peripapillary vascular density in episodic and chronic migraine cases without aura

BACKGROUND

Migraine is a neurovascular disease that can cause ocular and systemic ischemic damage. Despite from aura, a limited number of studies have considered the effect of the chronic migraine in cases without aura. Our aim was to evaluate the differences in the retinal and optic disk microvasculature among episodic and chronic migraine cases without aura using optical coherence tomography angiography (OCTA) imaging.

METHODS

45 cases with migraine, and 25 control subjects were included in this prospective, cross-sectional study. OCTA was performed at 3 × 3 mm and 6 × 6 mm of the macula and at 4.5 × 4.5 mm of the optic disk. Retinal nerve fiber layer (RNFL) thickness, ganglion cell complex thickness, and vessel densities of the optic nerve and macula were compared among the three groups: a control group, an episodic migraine without aura (EMWOA) group, and a chronic migraine without aura (CMWOA) group.

RESULTS

In EMWOA group, circumpapillary vascular density (cpVD) was not decreased significantly in any quadrants (all, p>0.05). Compared to the control group, CMWOA group had significantly lower RNFL thickness in superior-temporal quadrants (p = 0.002 and 0.006, respectively), while cpVD differed only in the temporal quadrant and temporal inferior sector (p = 0.002 and p = 0.009, respectively).

CONCLUSIONS

Temporal peripapillary perfusion is valuable in the follow-up of chronic migraine cases. Longitudinal studies are needed to determine the place of OCTA in the follow-up of migraine.

Optical coherence tomography angiography analysis of changes in the retina and the choroid after hemodialysis for end stage kidney disease

PURPOSE

To study effects of hemodialysis (HD) on retinal and choroidal vasculature in patients with end-stage kidney disease (ESKD) using optical coherence tomography angiography (OCTA).

METHODS

In this prospective study, we investigated eyes of patients undergoing hemodialysis for ESKD from Mondor University Hospital. Only one eye/patient was considered. Subfoveal choroidal thickness (SCT) was measured on enhanced-depth imaging optical coherence tomography (EDI-OCT) before and after the hemodialysis session. OCTA was used to extract retinal vascular density (superficial and deep capillary plexus, SCP, DCP) and choriocapillaris non-perfusion. Clinical, demographic and biological parameters (Blood B-Nitric Peptid rate prior to HD session) were reviewed.

RESULTS

Twenty patients (mean age 53.2 ± 13.6 years, 10 males and 10 females) were included in this prospective study. SCT significantly decreased after the HD session (234.3 ± 56.14 µm before HD to 211.9 ± 60.79 µm after hemodialysis (Wilcoxon signed-rank test, p = 0.003)). Non-perfusion in the choriocapillaris significantly increased after HD (41.65 ± 3.58 before HD, 42.95 ± 3.19 after HD, p = 0.036) while no significant modification of the vascular density was observed in the retinal vasculature (SCP, DCP) around the macular zone or the optic nerve. An increased plasma B-Nitric Peptide (BNP) level prior to the onset of the HD session was significantly correlated with the decrease of the SCT (r = 0.45, p = 0.043).

CONCLUSION

Hemodialysis in patients with ESKD is associated with a significant decrease in SCT and an increase in non-perfusion in the choriocapillaris on OCTA. A High BNP level prior to the onset of the hemodialysis appears to be correlated with the decrease in SCT.

Impact of Fluoride Exposure on Rat Placenta: Foetal/Placental Morphometric Alterations and Decreased Placental Vascular Density

Inorganic fluoride is a geogenic and anthropogenic contaminant widely distributed in the environment and commonly identified in contaminated groundwater. There is limited information on the effect of fluoride exposure on pregnancy. The aim of this study was to evaluate possible placental alterations of fluoride exposure in a rat model simulating preconception and pregnancy exposure conditions in endemic areas. Fluoride exposure was administered orally to foetuses of dams exposed to 2.5 and 5 mg fluoride/kg/d. Foetal weight, height, foetal/placental weight ratio, placental zone thickness, levels of malondialdehyde (MDA) and vascular endothelial growth factor-A (VEGF-A) and vascular density in placental tissue were evaluated. The results showed a nonlinear relationship between these outcomes and the dose of fluoride exposure. In addition, a significant increase in the fluoride concentration in placental tissue was observed. The group that was exposed to 2.5 mg fluoride/kg/d had a greater increase in both MDA levels and VEGF-A levels than the higher dose group. A significant increase in the thickness of the placental zones and a decrease in the vascular density of the labyrinth zone area were also observed in the fluoride-exposed groups. In conclusion, the data obtained demonstrate that fluoride exposure results in morpho-structural alterations in the placenta and that non-monotonic changes in MDA, VEGF-A levels and placental foetal weight ratio were at environmentally relevant concentrations.

Distribution of the Retinal Microcirculation Based on the Morphology of Peripapillary Atrophy in High Myopia

INTRODUCTION

The objective of this study was to evaluate the retinal microvasculature of the optic nerve head and macula in high myopia (HM), investigate the association between the vascular parameters and peripapillary atrophy (PPA) deformation, and assess and identify the PPA morphology changes during the development of HM.

METHODS

One hundred sixty-seven right eyes from 167 HM patients were enrolled in this cross-sectional study. Using the optical coherence tomography angiography (OCTA) and fundus camera, we evaluated the following parameters: radian and type of PPA, intrapapillary vascular density (IVD), peripapillary vascular density (PVD), macular vascular density (MVD), and foveal avascular zone (FAZ). Based on the PPA radian, subjects were divided into four groups: the non-PPA, temporal PPA, advanced PPA, and annular PPA. At the same time, the above parameters were compared between the groups using analysis of variance (ANOVA) and least significant difference test.

RESULTS

Total enrolled patients were divided into the non-PPA group (22 eyes), temporal-PPA group (70 eyes), advanced-PPA group (60 eyes), and annular-PPA group (15 eyes). The results showed that the PVD in the annular-PPA group was smaller than that in the non-PPA group, especially in the superonasal, nasosuperior, nasoinferior, inferotemporal, temporoinferior, and superotemporal directions (F = 4.059, 5.014, 2.830, 4.798, 5.892, 3.439; p < 0.05). Notably, the PVD showcased the highest value in temporal, followed by that in superior and inferior, and the lowest in the nasal. Concerning the fovea deep macular vascular density, FAZ area, and subfoveal choroidal thickness in the annular-PPA group, they were less than those of the rest of the groups (p < 0.05).

CONCLUSION

The retinal microvasculature differed significantly in HM according to the PPA morphology. In addition to PVD and SFCT, the PPA can also affect FAZ. Finally, we speculated that PVD demonstrated better predictability of myopic progression than MVD.

Comparison of the vessel density measurements of the macula, optical disc, and peri-papillary region between ocular hypertension patients and healthy controls

OBJECTIVE

To evaluate Optical Coherence Tomography Angiography (OCT-A) findings in patients with Ocular Hypertension (OHT) and compare them with healthy individuals.

METHODS

Thirty-four patients with ocular hypertension (OHT) and 22 healthy individuals were included in the study. Foveal thickness, retinal vascular density in superficial and deep capillary plexus and choriocapillaris, foveal avascular zone (FAZ), acircularity index (AI), foveal vessel density (FD), non-flow area, capillary and all vessel densities in the peripapillary area and the disc were automatically measured using the Angiovue software of OCT-A and compared between groups.

RESULTS

The comparison of the macular OCT-A findings did not reveal a significant difference between the two groups in terms of central macular thickness, superficial and deep capillary plexus vessel density (p>0.05). The foveal avascular zone width was significantly higher in OHT subjects compared to the control group (0.30±0.08 µ and 0.25±0.11 µ, respectively; p = 0.04). The comparison of optic nerve OCT-A findings revealed that the whole-field vessel density (wVD) (p = 0.007), peripapillary vessel density (pVD) (p = 0.001), inferior, superior and temporal radial peripapillary capillary plexus vessel density (p = 0.006, p = 0.008, p = 0.02) and the mean retinal nerve fiber layer thickness (p = 0.02) were significantly lower in the OHT group.

CONCLUSIONS

Our findings suggest that the decrement in the optic disc vascular density and foveal avascular zone width was significantly higher in OHT subjects. The possible effect or role of these microvascular changes in terms of glaucoma development should be examined through further studies.

Time course study of optical coherence tomography angiography in patients with methanol induced optic neuropathy

INTRODUCTION

In countries where alcoholic beverages are legally prohibited, methanol toxicity usually occurs due to ingesting homemade alcoholic drinks. The initial ophthalmologic symptoms of methanol toxicity typically appear 6-48 h after ingestion, and the severity of symptoms varies widely from mild and painless decreased vision to no-light perception vision.

METHODS

This prospective study examines 20 patients with acute methanol poisoning within 10 days of use. Patients underwent ocular examinations, BCVA (Best Corrected Visual Acuity) recording, and OCTA (Optical Coherence Tomography Angiography) of the macula and optic disc. BCVA measurement and imaging were repeated one month and three months after intoxication.

RESULTS

There was a statistically significant reduction in superficial parafoveal vascular density (P-value = 0.026), inner retinal thickness (P-value = 0.022), RNFL (Retinal Nerve Fiber Layer) thickness (P-value = 0.031), and an increase in cup to disc ratio (P-value < 0.001), and central visual acuity (P-value = 0.002) in this time course. However, there was no statistically significant difference in FAZ (Foveal Avascular Zone) area (P-value = 0.309), FAZ perimeter (P-value = 0.504), FD-300 (Foveal density, vascular density within a 300 μm wide region of the FAZ) (P-value = 0.541), superficial vascular density (P-value = 0.187), deep foveal vascular density (P-value = 0.889), deep parafoveal vascular density (P-value = 0.830), choroidal flow area (P-value = 0.464), total retinal thickness (P-value = 0.597), outer retinal thickness (P-value = 0.067), optic disc whole image vascular density (P-value = 0.146), vascular density inside the disc (P-value = 0.864), or peripapillary vascular density (P-value = 0.680) at different times.

CONCLUSION

Over time, methanol poisoning can cause changes in retinal layers thickness, vasculature, and optic nerve head. The most important changes include cupping of the optic nerve head, reduction in RNFL thickness, and inner retinal thickness.

Relationship between choroidal thickness and vascular density in young healthy population

BACKGROUND AND PURPOSE

The purpose is to analyze choroidal vascular density (VD) in healthy individuals and to compare it with choroidal thickness (CT).

MATERIALS AND METHODS

Cross-sectional study enrolling healthy individuals between 18 and 35 years old of Caucasian race and with an axial length (AL) 21-26 mm. Choroid was imaged with swept-source optical coherence tomography angiography (OCTA) Triton DRI (Topcon) and a macular cube of 6 x 6 mm was obtained. CT values were automatically given by the software. VD values were obtained through codifying colors of the VD map into numbers.

RESULTS

102 (51 patients) were analyzed. Mean age was 27.32 ± 3.94 years old, mean intraocular pressure was 18.07 ± 2.38 mmHg, and mean AL was 23.71 ± 0.66 mm. CT was higher in the vertical axis and lower when approaching nasal and temporal sides. The highest CT was in superior macula. The highest choroidal VD were in the fovea and in the juxtapapillary region. The lowest choroidal VD were found in superior and inferior macular areas. Moderate inverse correlations between CT and choroidal VD were found in the juxtapapillary and inferior regions.

CONCLUSIONS

The choroid has a thickness pattern that differs from retina. Choroidal vessels represent a very high percentage of choroid in the peripapillary region and in the fovea. On the contrary, superior and inferior macula reveals low values of VD.

Salt-sensitive hypertension after reversal of unilateral ureteral obstruction

The incidence of ureter obstruction is increasing and patients recovering from this kidney injury often progress to chronic kidney injury. There is evidence that a long-term consequence of recovery from ureter obstruction is an increased risk for salt-sensitive hypertension. A reversal unilateral ureteral obstruction (RUUO) model was used to study long-term kidney injury and salt-sensitive hypertension. In this model, we removed the ureteral obstruction at day 10 in mice. Mice were divided into four groups: (1) normal salt diet, (2) high salt diet, (3) RUUO normal salt diet, and (4) RUUO high salt diet. At day 10, the mice were fed a normal or high salt diet for 4 weeks. Blood pressure was measured, and urine and kidney tissue collected. There was a progressive increase in blood pressure in the RUUO high salt diet group. RUUO high salt group had decreased sodium excretion and glomerular injury. Renal epithelial cell injury was evident in RUUO normal and high salt mice as assessed by neutrophil gelatinase-associated lipocalin (NGAL). Kidney inflammation in the RUUO high salt group involved an increase in F4/80 positive macrophages; however, CD3+ positive T cells were not changed. Importantly, RUUO normal and high salt mice had decreased vascular density. RUUO was also associated with renal fibrosis that was further elevated in RUUO mice fed a high salt diet. Overall, these findings demonstrate long-term renal tubular injury, inflammation, decreased vascular density, and renal fibrosis following reversal of unilateral ureter obstruction that could contribute to impaired sodium excretion and salt-sensitive hypertension.

Optical coherence tomography angiography measurements in multiple sclerosis: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

Recent literature on multiple sclerosis (MS) demonstrates the growing implementation of optical coherence tomography-angiography (OCT-A) to discover potential qualitative and quantitative changes in the retina and optic nerve. In this review, we analyze OCT-A studies in patients with MS and examine its utility as a surrogate or precursor to changes in central nervous system tissue.

METHODS

PubMed and EMBASE were systematically searched to identify articles that applied OCT-A to evaluate the retinal microvasculature measurements in patients with MS. Quantitative data synthesis was performed on all measurements which were evaluated in at least two unique studies with the same OCT-A devices, software, and study population compared to controls. A fixed-effects or random-effects model was applied for the meta-analysis based on the heterogeneity level.

RESULTS

The study selection process yielded the inclusion of 18 studies with a total of 1552 evaluated eyes in 673 MS-associated optic neuritis (MSON) eyes, 741 MS without optic neuritis (MSNON eyes), and 138 eyes without specification for the presence of optic neuritis (ON) in addition to 1107 healthy control (HC) eyes. Results indicated that MS cases had significantly decreased whole image superficial capillary plexus (SCP) vessel density when compared to healthy control subjects in the analyses conducted on Optovue and Topcon studies (both P < 0.0001). Likewise, the whole image vessel densities of deep capillary plexus (DCP) and radial peripapillary capillary (RPC) were significantly lower in MS cases compared to HC (all P < 0.05). Regarding optic disc area quadrants, MSON eyes had significantly decreased mean RPC vessel density compared to MSNON eyes in all quadrants except for the inferior (all P < 0.05). Results of the analysis of studies that used prototype Axsun machine revealed that MSON and MSNON eyes both had significantly lower ONH flow index compared to HC (both P < 0.0001).

CONCLUSIONS

This systematic review and meta-analysis of the studies reporting OCT-A measurements of people with MS confirmed the tendency of MS eyes to exhibit reduced vessel density in the macular and optic disc areas, mainly in SCP, DCP, and RPC vessel densities.

Butyrate promotes post-stroke outcomes in aged mice via interleukin-22

Aging increases the risk of stroke, may exacerbate neuroinflammatory responses, reduce angiogenesis, and promote white matter damage post-stroke, all of which contribute to long-term functional recovery. Butyric acid, an important gut microbial metabolite, showed the highest correlation with the outcomes of ischemic stroke, and butyrate was selected as an effective treatment for aged stroke mice. Here, we tested the neurorestorative effect and potential therapeutic mechanisms of butyrate in aged mice with stroke. Aged male C57BL/6 J mice (17-19 months) were subjected to photothrombotic stroke. We performed butyrate supplementation in the drinking water for 3 weeks before surgery until 14 days after the stroke. At 14 days after ischemic stroke, white matter damage, leukocyte infiltration, and blood-brain barrier permeability were all decreased in the aged stroke mice that received the butyrate treatment, which also improved neurological outcomes by stimulating angiogenesis. Stroke reduces the level of interleukin-22 (IL-22) and butyrate treatment significantly enhanced IL-22 expression in the brain. To further validate the mechanisms of butyrate promoting neurological function after stroke, monoclonal antibodies were used to block IL-22 in aged stroke mice when butyrate treatment was provided. Blocking IL-22 in butyrate-treated aged stroke fails to improve functional outcomes and attenuated butyrate-induced angiogenesis, increased axon/white matter density and blood-brain barrier (BBB) integrity, but has no effect on inflammatory cells infiltration. In conclusion, butyrate improves outcomes in aged mice after stroke by promoting angiogenesis and BBB integrity and reducing leukocyte infiltration. To some extent, IL-22 may contribute to butyrate treatment induced vascular remodeling and increased BBB integrity responses in aged stroke mice.

Subserosal vascular density predicts oncological features of T2 gallbladder cancer

PURPOSE

Tumor sidedness (hepatic side vs. peritoneal side) reportedly predicts microvascular invasion and survival outcomes of T2 gallbladder cancer, although the actual histopathological mechanism is not fully understood.

METHODS

The clinical relevance of tumor sidedness was revisited in 84 patients with gallbladder cancer using histopathological analysis of the vascular density of the gallbladder wall.

RESULTS

Hepatic-side tumor location was associated with overall survival (OS) (hazard ratio [HR], 13.62; 95% confidence interval [CI], 2.09-88.93) and recurrence-free survival (RFS) (HR, 8.70; 95% CI, 1.36-55.69) in T2 tumors. The Adjusted Kaplan-Meier curve indicated a clear survival difference between T2a (peritoneal side) and T2b (hepatic side) tumors (P = 0.006). A review of 56 pathological specimens with gallbladder cancer and 20 control specimens demonstrated that subserosal vascular density was significantly higher on the hepatic side of the gallbladder, regardless of the presence of cancer (P < 0.001). Multivariate analysis also confirmed that higher subserosal vascular density was significantly associated with poor OS (HR, 1.73; 95% CI, 1.10-2.73 per 10 microscopic fields) and poor RFS (HR, 1.62; 95% CI, 1.06-2.49) in T2  gallbladder cancer.

CONCLUSION

Higher subserosal vascular density may account for the higher incidence of cancer spread and the poor prognosis of T2b gallbladder cancer.

Quantitative analysis of retinal microvascular structure and correlation with ocular parameters: A normative database of pediatric OCT angiography

PURPOSE

To analyze the vascular structure of the healthy pediatric population using optical coherence tomography angiography (OCTA), and to investigate its relationship with ocular parameters.

MATERIALS AND METHOD

This cross-sectional, prospective study included 142 eyes of 71 healthy subjects aged 8-18 years. All patients underwent a complete ocular assessment, biometric evaluation and OCTA analysis. Anterior chamber depth, axial length, corneal thickness values were also reported and their relationship with OCTA measurements was evaluated.

RESULTS

There was no statistical difference between girls and boys in terms of demographic characteristics (p>0.05). Neither vascular density in the deep and superficial capillary plexus nor FAZ area was significantly related to the ocular parameters or age of any patient in the study.

CONCLUSIONS

Despite the relatively small number of participants, this study may represent normative data for the Turkish pediatric population. It was also shown that vascular density and FAZ area in childhood are not affected by age, axis length, anterior chamber depth, cornea and foveal thickness.

Choriocapillary regional characteristics in idiopathic macular holes using optical coherence tomography angiography

PURPOSE

To evaluate the characteristics of vascular density (VD) of the retinal capillary plexuses in idiopathic macular hole (IMH), the fellow eye, and healthy control eyes by optical coherence tomography angiography (OCTA).

METHODS

A retrospective cases series study involving 20 unilateral eyes (20 patients) with IMH, the unaffected fellow eyes (n = 20) and 20 health controls, with age- and sex-matched, was conducted in Shanxi Eye Hospital from January 2019 to December 2021. VD of the retinal capillary plexuses measurements were obtained by OCTA.

RESULTS

Four quadrants of superficial capillary plexuses (SCP) in IMH eyes were not significant compared with that in the unaffected fellow eyes (all P > 0.05). The four quadrants of deep capillary plexuses (DCP) in IMH eyes were lower than that in the unaffected fellow eyes (all P < 0.05). Different regions retinal thickness in the IMH eyes was higher than that in the unaffected fellow eyes (all P < 0.05). a significant negative correlation between deep vessel density and retinal thickness in different quadrants among IMH eyes (all P < 0.05). Additionally, the correlation between the vascular density of SCP and retinal thickness was significant in macular fovea area (= 0.519, P = 0.019). <0.001.

CONCLUSIONS

The morphology of retina and choroid in idiopathic macular hole is different from that in fellow eye. The thickness of choroid in the fovea area of the unaffected eye also showed a decreasing trend. Taken together, the mechanism of macular hole may be further understood, that is, the decrease of choroid thickness may occur before the macular hole formation. It was verified again that the choroidal blood flow area in macular fovea of IMH patients was significantly lower than that in fellow eyes and healthy eyes.

Optical coherence tomography angiography analysis of microvascular abnormalities and vessel density in treatment-naïve eyes with diabetic macular edema

Background

The aim of this study was to evaluate the structural retinal vascular integrity using optical coherence tomography angiography (OCTA) in treatment-naïve eyes with diabetic macular edema (DME) and to compare it with findings in diabetic eyes without DME.

Methods

In this prospective study, 70 eyes with diabetic retinopathy were included (37 eyes with DME and 33 eyes without DME). The medical records, including swept-source optical coherence tomography and 9 × 9 mm swept-source OCTA images were reviewed and compared between DME and non-DME groups. Microaneurysms, intraretinal microvascular abnormalities (IRMA), areas of capillary non perfusion, foveal avascular zone (FAZ), and capillary vascular density (CVD) were analyzed in the superficial capillary plexus (SCP) and the deep capillary plexus (DCP).

Results

Compared to the non-DME eyes, DME eyes had more microaneurysms in the SCP and the DCP (p = 0,039 and p = 0,024 respectively), more IRMA in the SCP (p = 0,005), larger areas of capillary non perfusion in the SCP and the DCP (p = 0,026 and p = 0,02 respectively) and larger FAZ in both plexuses (p = 0,048 in the SCP and p = 0,012 in the DCP). The CVD in the DCP was lower in DME eyes compared to non-DME eyes (p = 0,007). The severity of DME was significantly correlated to the number of microaneurysms and to the FAZ surface. Central macular thickness was significantly correlated with the number of microaneurysms in the DCP, the surface of capillary non perfusion areas and the FAZ area in both plexuses.

Conclusions

OCTA with a 9 × 9 mm field of view showed that the retinal vascular integrity regarding the number of microaneurysms, the number of IRMA, the surface of capillary non perfusion areas, the FAZ area and the CVD, was significantly more impaired in DME eyes compared to diabetic eyes without DME. The DCP seemed to be more affected in diabetic eyes with and without DME than the SCP.

Macular and peripapillary optical coherence tomography angiography metrics in thyroid-associated ophthalmopathy with chorioretinal folds

PURPOSE

To evaluate macular and radial peripapillary capillary (RPC) microvascular densities and the thickness of the retinal nerve fiber layer (RNFL) in thyroid-associated ophthalmopathy (TAO) with chorioretinal folds (CRFs) and the associations of these characteristics with visual function.

METHOD

A cross-sectional study was performed at the Ophthalmology Department of the Sun Yat-sen Memorial Hospital from March 2018 to August 2021. All patients underwent ocular examination, ophthalmic function tests and optical coherence tomography angiography (OCTA). The microvascular densities in the macula and optic papilla in the TAO with CRFs or without CRFs. Correlation analyses were used to examine the association of microvascular density and visual function.

RESULTS

Ten TAO patients with CRFs (CRF group, 20 eyes) and 10 TAO patients without CRFs (NCRF group, 20 eyes) were recruited for the study. Visual function measurements, including best-corrected visual acuity (BCVA), were found to be worse in the CRF group (all p < 0.05). The macular whole-image vessel density in the superficial layer (SLR-mwiVD) was significantly decreased in the CRF group (p < 0.05). The RPC whole-image vessel density (RPC-wiVD) was significantly decreased in the CRF group (p < 0.05), particularly in the temporal subfields. The P100 amplitude of visual evoked potentials (VEPs) was positively associated with SLR-mwiVD and RPC-wiVD. The thickness of RNFL in the CRF group was obviously thicker than that in the NCRF group (p < 0.05).

CONCLUSIONS

Our study showed decreased microvascular density of the macula and RPC and thicker RNFL in TAO patients with CRFs. CRFs with decreased microvascular density should be regard as an indicator of visually threatening conditions.

Quantitative vessel density analysis of macular and peripapillary areas by optical coherence tomography angiography in adults with primary nephrotic syndrome

PURPOSE

To compare the microvascular parameters of macular and peripapillary areas in adults with primary nephrotic syndrome (PNS) and healthy controls (HCs).

METHODS

In this cross-sectional study, optical coherence tomography angiography (OCTA) was used to evaluate the changes in retinal microvascular in 37 adult patients with PNS and 30 HCs in this study. All subjects underwent OCTA for measuring vascular density (VD), perfusion density (PD), and foveal avascular zone (FAZ) in the superficial capillary plexus (SCP) and optical coherence tomography (OCT) for measuring central macular thickness (CMT) and retinal nerve fiber layer (RNFL) thickness. The following clinical data of the PNS group were collected: hemoglobin, platelet, total protein, albumin, prealbumin, creatinine, urea nitrogen, glomerular filtration rate, blood lipid, urinary protein, urine microalbumin, urine microalbumin/creatinine, 24-h urine volume, and 24-h urine protein quantification. The OCTA data were compared between patients with PNS and HCs, and the correlation between the OCTA data and clinical data was analyzed in the PNS group.

RESULTS

VD and PD in the macular area of the PNS group were significantly lower than those in the HC group (VD: 17.025 ± 2.229 vs. 18.290 ± 0.721, P = 0.001; PD: 0.417 ± 0.058 vs. 0.450 ± 0.019, P = 0.003). No significant differences in the FAZ area and perioptic disc microvascular parameters were observed between the two groups, and patients in the PNS group showed consistent changes in the left and right eyes. VD and PD in the central macular area were positively correlated with plasma prealbumin level (VD: ρ = 0.541, P = 0.001; PD: ρ = 0.562, P < 0.001) and negatively correlated with urinary protein level (VD: ρ = -0.579, P < 0.001; PD: ρ = -0.596, P < 0.001).

CONCLUSIONS

In adult patients with PNS, the decrease in VD and PD was mainly occurred in the macular area. Partly vascular density of the macular area was positively correlated with plasma prealbumin level and negatively correlated with urinary protein level. OCTA provides a convenient, non-invasive and effective method for evaluating and monitoring retinal microcirculation damage in patients with PNS.

Evaluation of macular vascular density and foveal avascular zone changes by optical coherence tomography angiography (OCT-A) after intravitreal dexamethasone implant in diabetic macular edema resistant to Anti-VEGF treatment

PURPOSE

Analysis of foveal avascular zone (FAZ) width and vascular density (VD) changes before and after intravitreal dexamethasone implant (IDI) treatment in diabetic macular edema (DME) patients resistant to anti-VEGF treatment.

METHODS

In this retrospective study, patients who were regularly treated with at least 5 doses of intravitreal Anti-VEGF (bevacizumab, ranibizumab or aflibercept) for DME and whose DME continued were considered resistant to Anti-VEGF and were treated with IDI for the first time. Thirty-four eyes of 34 patients were included in the study. FAZ and VD values of optical coherence tomography angiography (OCT-A) scans at 0, 1 and 3 months were examined.

RESULTS

In OCT-A measurements, the pre-IDI superficial plexus FAZ (SFAZ) area (0.350 ± 0.120 mm²) was decreased at 1 (0.292 ± 0.132 mm², p < 0.001) and at 3 months (0.311 ± 0.153 mm², p = 0.017). Pre-IDI deep plexus FAZ (DFAZ) area (0.651 ± 0.313 mm²) was decreased at 1-month post-IDI (0.481 ± 0.247 mm², p < 0.001) while no significant change was observed at 3 months (0.575 ± 0.259 mm², p = 0.197). There was no significant change in the mean post-IDI total VD rate in both superficial (pre 39.2% ± 2.4; 1st month 39.2% ± 2.6%; 3rd month 39.5% ± 3.4%) and deep retinal plexus (pre 43.3% ± 2.6%; 1st month 43.5 ± 2.8%; 3rd month 43.6% ± 4.6%) (p = 0.408 and p = 0.607, respectively).

CONCLUSION

The study showed that IDI caused a significant decrease in the FAZ area without any change in VD in patients with DME resistant to the anti-VEGF agents. IDI might be related to a decrease in the macular ischemia secondary to diabetic retinopathy.

Histology and Vascular Architecture Study of Keloid Tissue to Outline the Possible Terminology of Keloid Skin Flaps

BACKGROUND

Using the keloid "epidermis" to cover a wound is widely used during treatment for keloids. Many flap terminologies have been used in literature. However, the definition of the flap is not well established. Here, we refined the definition of the flap and associated terminology and explored the survival mechanism of the 'flap' through histological analysis and blood supply studying.

METHODS

Histology and vascular study of keloid was carried out with keloid and its surrounding normal skin tissue which were collected from keloid patients following keloid resection operations. The histological structures and thicknesses of epidermal and subepidermal of the keloids were analyzed and measured using hematoxylin & eosin (H&E) staining. Vascular density and blood perfusion in the subepidermal layer of keloids (KDS) were analyzed using CD31 immunohistochemical staining and a laser speckle contrast imaging system (LSCI), respectively. The vascular network in KDS was visualized by CD31 immunofluorescence staining and three-dimensional reconstruction.

RESULTS

29 pieces of keloid and its surrounding normal skin tissue sample from ten patients were collected. Keloid samples were about 2 cm wide and 5 cm long. The normal skin samples were about 2 to 3 mm in width. The thickness of epidermal layer of keloids was (136.4 ± 35.3) μm, and the thickness of epidermal layer of surrounding normal skin was (78.8 ± 13.9) μm. There was statistical thickness difference between the two layers, t(20) = 7.469, P < 0.001. The total thickness of keloid epidermal and subepidermal layers was 391.4 ± 2.3 μm. The vascular density (13.9 ± 3.4/field) and blood flow perfusion (132.7 ± 31.3) PU in KDS were greater than that of surrounding normal skin (7.8 ± 2.3/field, 73.9 ± 17.9 PU), P < 0.001. Horizontally distributed vessels with several vertical branches were observed in 3D vascular network reconstruction.

CONCLUSION

The epidermal layer of keloid is thicker than that of surrounding normal skin. There is a vascular network structure under it. The vessels mainly locate at a depth of about 150 to 400 μm from the surface of keloid epidermis, randomly distribute and run parallel to the epidermis. Based on these characteristics which may ensure an adequate blood supply, we propose the concept of a "keloid subepidermal vascular network flap."

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Optical coherence tomography angiography in healthy children: normative data and age-related changes in microvascular structure of the optic disk and macula

PURPOSE

To determine normative data and reference ranges according to age groups by measuring the foveal avascular zone (FAZ), superficial capillary plexus vascular density (SCP-VD), deep capillary plexus vascular density (DVP-VD), radial peripapillary capillary plexus vessel density (RPC-VD), and peripapillary retinal nerve fiber layer (ppRNFL) in healthy children and to determine the age and sex-related changes of these values.

METHODS

This prospective study included data from 370 eyes of 370 healthy children (202 girls, 168 boys) aged 7-18 years. Participants were divided into four groups according to their age. Optical coherence tomography angiography (OCTA) measurements were taken using AngioVue (Avanti; Optivue).

RESULTS

No statistically significant difference was observed in terms of FAZ, SCP-VD, DCP-VD, RPC-VD, and ppRNFL thickness values according to the age groups (except the RPC-VD superior) (p > 0.05 for all). VDs in all deep parafoveal regions in groups 1 and 2 were higher in girls. While FAZ values were higher in girls in all age groups (statistically significant in groups 1, 3, and 4), ad SPD and DPD values were higher in boys in all age groups (statistically significant in group 1 and 2 for SPD, and group 1 and 3 for DPD).

CONCLUSIONS

We report normal reference ranges for macula and disk vessel density and ppRNFL parameters in healthy children aged 7-18 years using OCTA. These normative values could be useful in diagnosing retina and optic disk disease early in childhood.

Analysis of Retinal Layers' Thickness and Vascular Density after Successful Scleral Buckle Surgery

Purpose:

To investigate retinal layers’ thickness and vascular density after successful scleral buckle surgery using the optical coherence tomography angiography (OCTA) method.

Methods:

In this prospective interventional case-control study, 24 patients with macular-off rhegmatogenous retinal detachment (RRD) were included after performing successful reattachment by scleral buckling. Retinal layers’ thickness and vascular density were assessed in the patients using the OCTA method compared to normal fellow eyes as controls 10 months postoperation.

Results:

Inner retinal layers showed no significant difference, but there was a significant reduction in outer central 1-mm retinal layers’ thickness. Outer plexiform-Bruch's membrane (153.1 ± 24.3 μm vs. 166.2 ± 15.1 μm, P = 0.003) and ellipsoid zone to Bruch's membrane (51.25 ± 9.3 μm vs. 57.35 ± 3.8 μm, P = 0.009) were thinner in the operated eyes compared to fellow eyes. Vascular density within a 300 μm wide region around the foveal avascular zone (FAZ) (foveal density-300) was significantly lower in the detached eyes (46.28% ± 7.12% vs. 51.01% ± 4.73%, P = 0.016), however, there was no difference in superficial and deep vascular density at 1-mm central circle. Superficial parafoveal vascular density was lower in the operated eyes (46.24% ± 5.30% vs. 49.52% ± 5.93%, P = 0.026) with no significant difference in deep parafoveal vascular density (49.93 ± 4.29% vs. 51.88% ± 4.79%, P = 0.137). There was no difference in FAZ area and perimeter between the two groups.

Conclusions:

Complete recovery of retinal thickness and vascular density did not achieve in the patients with RRD even after 10 months of reattachment by scleral buckling surgery. Superficial capillary vascular density was more affected than deep vascular density almost in the parafoveal area.

Quantification of macular perfusion in healthy children using optical coherence tomography angiography

Background

This study aimed at defining the variance of vessel density (VD) characteristics in the macula of children with normal eyes.

Methods

This was a cross-sectional study in which subjects with normal eyes aged 3–18 years were enrolled. The macula was scanned by optical coherence tomography angiography (OCTA). Four age groups as under 7 years, 7–10 years, 11–14 years and more than 14 years of age were defined. The influences of age, gender, and body mass index on VD were analyzed.

Results

A total of 108 normal eyes from 54 participants with a mean age of 10.9 years were enrolled in the study. At the superficial and deep retina capillary plexus (SCP and DCP) and choriocapillaris (CC), respectively, the mean VD of the fovea was 20.10%, 36.99%, and 75.67%; at parafovea, these measurements were 53.12%, 55.81%, and 69.76%; and at perifovea, these measures were 51.38%, 52.46%, and 73.47%. The median foveal avascular zone (FAZ) was 0.30 mm². No significant differences between superior-hemi VD and inferior-hemi VD were found in the studied plexuses. The VD at parafovea and perifovea CC differed significantly between groups. There was no variation in VD of macular retina and CC between eyes or sex. FAZ areas were different between genders.

Conclusions

No difference between eyes and genders in the retina and CC VD of macular area was noted. FAZ area was larger in male. Even though this is not a longitudinal study, it may provide us with hints about macular vascular development during puberty and clinical implications of OCTA in children.

Evaluation of retinal and optic nerve vasculature by optic coherence tomography angiography in Migraine with Aura

PURPOSE

This study aimed to evaluate the retina by optic coherence tomography angiography (OCTA) in patients with migraine with aura (MA) in comparison with healthy controls.

MATERIALS AND METHODS

A total of 60 patients with MA and 56 control subjects who applied to the Ophthalmology Clinic of Dicle University between January 2020 and February 2020 were included in this study. In all patients, the vascular density (VD) of the radial peripapillary capillaries (RPCs) and optic nerve head (ONH), the VD of deep and superficial macular vascular networks, and foveal avascular zone (FAZ) were measured.

RESULTS

Patients with MA showed reduced VD measurements of the nasal and inferotemporal ONH, inferonasal RPCs, and deep macular plexus. No statistically significant difference was observed in the superficial macular VD values between the study groups. The majority of patients with MA showed hypertrophy in the deep FAZ.

CONCLUSION

There was a decrease in VD measurements in the deep macular capillary plexus, ONH, and peripapillary capillaries and hypertrophy in the deep FAZ in patients with MA. According to these results, patients with MA may have an increased risk of developing ocular and systemic vascular complications. Therefore, OCTA can be used to evaluate systemic and ocular hypoperfusion in patients with MA.

Evaluation of parafoveal vascular density using optical coherence tomography angiography in patients with central serous chorioretinopathy

Using optical coherence tomography angiography (OCTA), we sought to evaluate parafoveal vascular density (VD) in patients with central serous chorioretinopathy (CSCR). Our study included 43 patients with a diagnosis of CSCR and 40 healthy controls. Ophthalmologic examination findings and OCTA measurements of the participants were retrospectively analysed. Of the 43 patients with CSCR, 31 were males (72%) and 12 were females (28%); the control group was 30 males (75%) and 10 females (25%) (p = 0.657). There were significant differences between affected eyes, unaffected eyes and healthy control eyes for all parameters in the superficial capillary plexus (SCP) VD and deep capillary plexus (DCP) VD (p < 0.05 for all values). It was also determined that the affected eyes had lower SCP-VD and DCP-VD than the unaffected eyes and that the unaffected eyes had lower SCP-VD and DCP-VD than the healthy control eyes (p < 0.05 for all values). While there were no significant differences in the deep foveal avascular zone (FAZ) area, the superficial FAZ area was larger in affected eyes than in both unaffected eyes and healthy control eyes (p < 0.05). In most areas, the SCP-VD and DCP-VD values were lower and the FAZ larger in the chronic group than in the acute group (p < 0.05). Retinal vascular changes were found in patients with both acute and chronic CSCR, and the fellow eyes of these patients were also affected. OCTA can therefore be considered an easily applicable, non-invasive screening option for evaluating the microvascular structure in these patients.

Change in retinal and choroidal microvascular structures after rhegmatogenous retinal detachment surgery and effects on visual recovery

PURPOSE

To investigate changes in retinal and choroidal microvascular structures in the macular region after surgery for rhegmatogenous retinal detachment (RRD) and their relationship to visual function at 3months.

METHODS

This prospective, cross-sectional study included 37 eyes of 37 patients who underwent surgery for RRD (pneumatic retinopexy and/or pars plana vitrectomy). All patients underwent a comprehensive ophthalmologic examination, including measurement of best-corrected visual acuity (BCVA, logMAR), anterior segment and fundus examination, and optical coherence tomography angiography (OCTA) imaging 3months postoperatively. The healthy fellow eyes formed the control group. OCTA was used for the assessment of macular vessel density (VD), foveal avascular zone (FAZ), central macular thickness, and choroidal and outer retinal flow rates.

RESULTS

The findings showed that the VD of the superficial and deep capillary plexuses were lower in the RRD group compared to the control group (P=0.012; P<0.001). The FAZ was larger in the RRD group (P=0.035). The choroidal flows in the 1 and 3mm² were lower in the RRD group (P<0.001). Superficial FAZ area and choroidal flow rate (1 and 3mm² areas) were moderately negatively correlated with BCVA (P=0.008; P=0.035; P=0.008).

CONCLUSIONS

Our study demonstrated that the FAZ was larger, and the choroidal flow rate was lower, in the RRD group compared to the control group. Choroidal flow rate was negatively correlated with postoperative BCVA. Ischemic events resulting from the RRD were likely the reason for these changes.

Early effects of viper envenomation on retina and optic nerve blood flow: An optical coherence tomography angiography study

In this study, the early retinal and optic nerve blood flows of patients exposed to Viper bite were evaluated with non-invasive optical coherence tomography angiography (OCTA) and compared with healthy controls. The retinal and optic disc OCTA data of 31 victims of viper bite (group S) without systemic envenomation clinical symptoms and 31 healthy controls (group C) were compared. Only patients with early signs of envenomation were included in the study. Optical coherence tomography angiographies were performed with RTVue XR Avanti with AngioVue software. Vascular densities in the whole image, foveal, parafoveal regions at the superficial and the deep capillary plexus segments were acquired and statistically analyzed. The flow area parameters were measured in the superficial retinal capillary plexus, deep retinal capillary plexus, outer retinal capillary plexus, and choriocapillaris layers of the macula in 1-mm and 3-mm diameter areas. The peripapillary flow areas were measured for the optic nerve head, vitreous, radial peripapillary capillary (RPC), and choroid in a 4.50-mm diameter area. Foveal and parafoveal thicknesses were also measured and compared. The average hospital admission time of the patients in group S was 1.24 ± 0.75 (0.50-3.00) hours. Age (p = 0.103) and gender (p = 0.714) were similar in both groups. Superficial (p = 0.010), deep flow areas (p = 0.034), and superficial parafoveal vascular density (p = 0.001) were significantly reduced in group S compared to group C. The outer retinal flow area (p < 0.001) increased significantly in group S. Nerve head flow area (p = 0.035), one of the optic disc flow areas, was found to be decreased in group S. Notably, foveal (p < 0.001) and parafoveal (p = 0.003) thicknesses and superficial (p = 0.001) and deep (p < 0.001) foveal vascular densities were greater in group S. Compared to group C, the superficial (p = 0.009) and deep (p = 0.009) foveal flow areas in the central foveal area with a diameter of 1 mm increased significantly in group S. Viper venom may cause blood flow changes in the retina and optic disc and an increase in retinal thickness in the early period although there are no signs of systemic envenomation.

Modifications of physical and functional integrity of the blood-brain barrier in an inducible mouse model of neurodegeneration

The inducible p25 overexpression mouse model recapitulate many hallmark features of Alzheimer's disase including progressive neuronal loss, elevated Aβ, tau pathology, cognitive dysfunction, and impaired synaptic plasticity. We chose p25 mice to evaluate the physical and functional integrity of the blood-brain barrier (BBB) in a context of Tau pathology (pTau) and severe neurodegeneration, at an early (3 weeks ON) and a late (6 weeks ON) stage of the pathology. Using in situ brain perfusion and confocal imaging, we found that the brain vascular surface area and the physical integrity of the BBB were unaltered in p25 mice. However, there was a significant 14% decrease in cerebrovascular volume in 6 weeks ON mice, possibly explained by a significant 27% increase of collagen IV in the basement membrane of brain capillaries. The function of the BBB transporters GLUT1 and LAT1 was evaluated by measuring brain uptake of d-glucose and phenylalanine, respectively. In 6 weeks ON p25 mice, d-glucose brain uptake was significantly reduced by about 17% compared with WT, without any change in the levels of GLUT1 protein or mRNA in brain capillaries. The brain uptake of phenylalanine was not significantly reduced in p25 mice compared with WT. Lack of BBB integrity, impaired BBB d-glucose transport have been observed in several mouse models of AD. In contrast, reduced cerebrovascular volume and an increased basement membrane thickness may be more specifically associated with pTau in mouse models of neurodegeneration.

Macular vascular changes in pregnant women with gestational diabetes mellitus by optical coherence tomography angiography

Background

Retinal capillary is vulnerable to diabetes, whether gestational diabetes mellitus (GDM) eyes without clinical retinopathy have capillary abnormalities has not been well studied. To observe the microvasculature changes in eyes of GDM women compared with normoglycemic pregnant women and non-pregnant women by optical coherence tomography-angiography (OCT-A).

Methods

GDM women, age-matched normoglycemic pregnant women and non-pregnant women were included in this study. All subjects were examined by OCT-A, vascular density and macular foveal parameters were measured automatically.

Results

Thirty eight non-pregnant women (NC group), thirty pregnant women without GDM (PC group), and thirty one GDM women (GDM group) were included in this study. There was a significant reduction of vascular density in superficial capillary layer, but an increase in deep capillary layer in PC and GDM groups (P < 0.001). When in terms of the average vascular density, the difference was insignificant among these three groups. Although all the measurements were similar between PC and GDM groups, more capillary “dropout” changes were detected in GDM group. Unexpectedly, the abnormal changes of central macular thickness thinning and foveal avascular zone enlargement seen during pregnancy were improved when compared to PC group.

Conclusions

The changes of vascular density implied the redistribution of capillary network from superficial to deep layer under pregnancy and GDM states. Although the transient hyperglycemia aggravates the changes of capillary “dropout”, GDM group revealed the improvement of central macular thickness thinning and foveal avascular zone enlargement during pregnancy.

Macular vessel density in patients recovered from COVID 19

Purpose

The purpose is to evaluate macular vascular densities (VDs) using optical coherence tomography angiography (OCTA) in patients effected by coronavirus disease-2019 (COVID-19).

Methods

The superficial (SF) and deep macular VD of 50 patients with SARS CoV2 pneumonia who had positive polymerase chain reaction (PCR) tests and who recovered after receiving treatment and 55 healthy age- and gender-matched controls were compared using OCTA. Blood inflammation parameters were also recorded.

Results

There was no statistically significant difference between the two groups in terms of age and gender (p = 0.147 and p = 0.504, respectively). Nor was there a difference with respect to smokers between the two groups (p = 0.231). In COVID-19 patients, the VDs in superior hemi quadrant, superior quadrant and inferior quadrant, were significantly lower (p = 0.033, p = 0.029 and p = 0.042, respectively) in superficial plexus. It was also significantly lower in parafovea, superior hemi and superior quadrants (p = 0.026, p < 0.001 and p = 0.004, respectively) in deep plexus. In addition, white blood cell and neutrophil counts were significantly negatively correlated with the VD of the deep parafovea, deep superior quadrant and deep superior hemi quadrant (p < 0.05). There was no difference between the patient and control groups in both superficial and deep foveal avascular zone (FAZ) (p = 0.101 and p = 0.691 respectively).

Conclusion

In COVID-19 disease, VD is low in some sectors in both SF and deep layers, but no change in FAZ. The effect of COVID 19 disease on the retina and whether it makes the retina sensitive to damage can only be understood with long-term follow-up.

Quantitative assessment of vascular density in diabetic retinopathy subtypes with optical coherence tomography angiography

Background

Quantitative assessment of vascular density (VD) of retinal and choriocapillaris (CC) in various stages of diabetic retinopathy (DR) using spectral domain optical coherence tomography angiography (SD OCTA).

Methods

188 eyes of 97 participants were recruited in this cross-sectional study. The macular OCTA (3x3mm) scan was performed and the computer algorithm assessed VD at the level of superficial capillary plexus (SCP), deep capillary plexus (DCP) and CC.

Results

All measured parameters were decreased in retinal VD at the more extreme stages of DR, with the exception of SCP foveal VD. There was a constant pattern of decrease in VD of CC from normal cases to cases of NDR and NPDR and then a slight increase occurred in the PDR stage but never touching the normal quantities. Age, fasting blood sugar, and years of diabetes mellitus were correlated with reduced VD in different segments. Multivariate linear regression analysis showed that best-corrected visual acuity (BCVA) was positively correlated with parafoveal VD at SCP and VD of foveal area at CC. VD of all subfields of macular area except foveal DCP VD showed reduced levels in diabetic macular edema (DME) patients compared to those without DME.

Conclusions

The findings of the study endorse retina VD changes as a potential biomarker for DR development before retinopathy becomes clinically evident. It seems that parafoveal VD of SCP and foveal VD of CC are good biomarkers to predict VA in the diabetic patients.

Perifoveal capillary changes in diabetic patients and association between severity and type of diabetes, visual acuity, and enlargement of non-flow area in the retinal capillary plexuses

BACKGROUND

The goal of this study was to evaluate the perifoveal capillary bed and to analyze areas of non-flow using optical coherence tomography angiography (OCT-A) in patients presenting with diabetic retinopathy (DR), correlating them to the severity of DR, type of diabetes and visual acuity (VA).

PATIENTS AND METHODS

The non-flow area (NFA) and foveal avascular zone (FAZ) in the superficial (SCP) and deep capillary plexus (DCP) were calculated using OCT-A imaging of patients with DR followed between July 2015 and March 2016 at the Jules Gonin Eye Hospital (Lausanne, Switzerland). Disease severity was classified using the Early Treatment Diabetic Retinopathy Study (ETDRS) classification. Analysis of variance was used to correct for correlation between eyes.

RESULTS

Seventy-eight eyes of 53 patients were included (29 men; 44 right eyes). There were 45 eyes with non-proliferative DR (NPDR; stage 1 [n=14], stage 2 [n=7], and stage 3 [n=24]) and 33 with proliferative DR (PDR; stage 1 [n=17], stage 2 [n=16]) included, among which 26 had type I diabetes and 52 type II diabetes. The mean Best Corrected Visual Acuity (BCVA) was 78.5 letters. The mean NFA in the SCP differed according to diabetes type and stage of DR (type 1 diabetes: NPDR, 0.76±0.3, PDR, 1.24±0.7; type 2 diabetes: NPDR, 1.46±0.7, PDR, 1.57±0.7).

CONCLUSION

The NFA, measured by OCTA, may be a useful indicator of DR severity, especially in the superficial capillary plexus. Loss of visual acuity might be correlated with increasing NFA (excluding the FAZ or not), primarily among patients with type II diabetes and NPDR.

Morphological changes in and quantitative analysis of macular retinal microvasculature by optical coherence tomography angiography in hypertensive retinopathy

Hypertension is a serious global health problem. Hypertensive retinopathy is generally considered to be a predictor of vascular disease elsewhere in the human body. In the past few decades, a variety of grading systems have been proposed for hypertensive retinopathy. However, these grading systems have some limitations. This study utilized optical coherence tomography angiography (OCTA) to investigate the morphological changes and macular retinal microvasculature in depth among 100 patients with hypertensive retinopathy and 66 healthy participants. Five main pathological changes were discovered in hypertensive retinopathy, as follows: focal capillary sparsity, scattered microangioma, focal macular arch ring defects, focal capillary disorder, and focal capillary nonperfusion at the levels of the superficial and deep vascular networks. In addition, we have found that the number of various pathological changes shows an increasing trend as hypertensive retinopathy progresses and may be related to renal damage. Finally, deep vessel density tended to decrease with progressive stages of hypertensive retinopathy and could be the best indicator to predict the risk of hypertensive retinopathy. Our study, therefore, proposes 3 stages of hypertensive retinopathy without macular edema according to the pathophysiology found by OCTA: stage 1 (only focal capillary sparsity), taking the place of KWB grade I; stage 2 (focal capillary sparsity and scattered microangioma), taking the place of KWB grade II; and stage 3 (focal capillary sparsity, scattered microangioma, focal capillary disorder, and nonperfusion), taking the place of KWB grade III. Hence, OCTA may be a potentially useful tool for evaluating the pathophysiology and staging of hypertensive retinopathy. Further longitudinal prospective studies are needed to confirm our findings.

Choroidal vessel density in unilateral hyperopic amblyopia using en-face optical coherence tomography

Background

Structural changes of the choroid, such as choroidal thickening, have been indicated in amblyopic eyes with hyperopic anisometropia as compared to fellow or healthy eyes. The purpose of the present study was to investigate choroidal vascular density (CVD) in children with unilateral hyperopic amblyopia.

Methods

This study included 88 eyes of 44 patients with unilateral amblyopia due to hyperopic anisometropia with or without strabismus and 29 eyes of 29 age-matched normal controls. The CVD of Haller’s layer was quantified from en-face images constructed by 3-dimensional swept-source optical coherence tomography images flattened relative to Bruch’s membrane. The analysis area was a 3 × 3-mm square of macula after magnification correction. Relationships between CVD and other parameters [best-corrected visual acuity (BCVA), refractive error and subfoveal choroidal thickness (SFCT)] were investigated, and CVDs were compared between amblyopic, fellow, and normal control eyes.

Results

Mean CVD was 59.11 ± 0.66% in amblyopic eyes, 59.23 ± 0.81% in fellow eyes, and 59.29 ± 0.74% in normal control eyes. CVD showed a significant positive relationship with SFCT (p = 0.004), but no relationships with other parameters. No significant differences in CVD were evident among amblyopic, fellow, and normal control eyes after adjusting for SFCT (p = 0.502).

Conclusions

CVD was unrelated to BCVA, and CVD did not differ significantly among amblyopic, fellow and normal control eyes. These results suggest that the local CVD of Haller’s layer is unaffected in unilateral hyperopic amblyopic eyes.

Vascular density of optic nerve head in diabetic retinopathy using optical coherence tomography angiography

Purpose

To measure optic nerve head (ONH) blood perfusion using optical coherence tomography angiography (OCTA) at various stages of diabetic retinopathy (DR).

Methods

One hundred seventy six eyes of 94 patients included in this retrospective single-centre cross-sectional study. The subjects were studied in normal, no diabetic retinopathy (NDR), non-proliferative diabetic retinopathy (NPDR) and proliferative retinopathy (PDR) groups. The eyes were subjected to AngioDisc ONH imaging using OCTA for papillary (Disc) and peripapillary (RPC) vascular density (VD) evaluation.

Results

The mean age of the participants was 56.08 ± 8.87 years and 34 (36.2 percent) were male. With increased DR severity, a statistically significant decrease in peripapillary VD was found. The study showed that only VD of the whole RPC (W-RPC) could be a valid biomarker in the staging assessment. VD of RPC, in all subsections, was considerably different from normal cases in the PDR group. Visual acuity was correlated with whole image ONH VD. The duration of DM, FBS, hyperlipidemia and DME had no effect on the ONH perfusion.

Conclusions

The study showed that only the W-RPC VD could be a reasonable marker in the staging assessment. VDs assessed by OCTA can be useful for assessing and tracking early ONH changes in DR patients.

Optical coherence tomography angiography characteristics of optic disc melanocytoma

Background

Optic disc melanocytoma (ODMC) was a benign pigmented intraocular tumor with the rare potential malignant transformation. This study was designed to evaluate tumor vasculature with optical coherence tomography angiography (OCTA) in ODMC.

Methods

Eyes of healthy individuals in a control group and of patients with ODMC were imaged by OCTA systems operating at 840 nm wavelengths and examined. The main outcome measures were OCTA images, qualitative evaluation of optic disc and tumor vasculature, quantitative vascular density (VD) and perfusion density (PD).

Results

One eye of ten normal volunteers and ten patients with ODMC were imaged. Eyes affected by ODMC as compared to the eyes of the control group (all P < 0.05). The healthy optic disc had radially-oriented vessels within the retina on OCTA. Optic disc melanocytoma was characterized by globular, demonstrated tortuous blood vessels, uneven thickness, and relatively disorganized intratumoral vasculature. The VD and PD within ODMC were significantly higher (12.360% ± 4.175, 0.316% ± 0.119%, P < 0.0001) than in normal optic discs (4.160% ± 2.290, 0.102% ± 0.0, 56%, P < 0.0001). No significant differences were established of the VD and PD in each single measurement zone (P > 0.05) between the ODMC and the control eyes. At 840 nm, OCTA could provide sufficient visualization of the tumor vasculature and better penetration through thicker tumors. The full thickness was visualized even in thicker tumors and highly pigmented lesions (> 2 mm). Interpretable OCTA images were obtained in 96% of the participants in whom imaging was attempted.

Conclusions

OCTA may provide a noninvasive, safe, and efficient technique for evaluating a variety of neoplasms including the growth and vascularity in ODMC. OCTA could facilitate the evaluation of the vascular abnormalities of tumors and the effect of melanin on the penetration of the OCTA beam was not significant.

The microvascular extracellular matrix in brains with Alzheimer's disease neuropathologic change (ADNC) and cerebral amyloid angiopathy (CAA)

BACKGROUND

The microvasculature (MV) of brains with Alzheimer's disease neuropathologic change (ADNC) and cerebral amyloid angiopathy (CAA), in the absence of concurrent pathologies (e.g., infarctions, Lewy bodies), is incompletely understood.

OBJECTIVE

To analyze microvascular density, diameter and extracellular matrix (ECM) content in association with ADNC and CAA.

METHODS

We examined samples of cerebral cortex and isolated brain microvasculature (MV) from subjects with the National Institute on Aging-Alzheimer's Association (NIA-AA) designations of not-, intermediate-, or high ADNC and from subjects with no CAA and moderate-severe CAA. Cases for all groups were selected with no major (territorial) strokes, ≤ 1 microinfarct in screening sections, and no Lewy body pathology. MV density and diameter were measured from cortical brain sections. Levels of basement membrane (BM) ECM components, the protein product of TNF-stimulated gene-6 (TSG-6), and the ubiquitous glycosaminoglycan hyaluronan (HA) were assayed by western blots or HA ELISA of MV lysates.

RESULTS

We found no significant changes in MV density or diameter among any of the groups. Levels of BM laminin and collagen IV (col IV) were lower in MV isolated from the high ADNC vs. not-ADNC groups. In contrast, BM laminin was significantly higher in MV from the moderate-severe CAA vs. the no CAA groups. TSG-6 and HA content were higher in the presence of both high ADNC and CAA, whereas levels of BM fibronectin and perlecan were similar among all groups.

CONCLUSIONS

Cortical MV density and diameter are not appreciably altered by ADNC or CAA. TSG-6 and HA are increased in both ADNC and CAA, with laminin and col IV decreased in the BM of high ADNC, but laminin increased in moderate-severe CAA. These results show that changes in the ECM occur in AD and CAA, but independently of one another, and likely reflect on the regional functioning of the brain microvasculature.

Optical coherence tomography angiography changes in macula-off rhegmatogenous retinal detachments repaired with silicone oil

PURPOSE

To evaluate the changes on optical coherence tomography angiography (OCTA) in macula-off rhegmatogenous retinal detachments (RRD) treated with pars plana vitrectomy (PPV) and silicone oil (SO) 5000-cSt tamponade.

MATERIALS AND METHOD

Forty-five eyes with macula-off RRD treated with PPV and SO tamponade were enrolled with the fellow eye being used as a control. OCT-A was obtained using the RTVue XR 100 Avanti (Optovue, Inc., Fremont, CA, USA) at the 1-week, 1-month, and 3-month postoperative visit. Retinal vascular density, choroidal flow area, retinal thickness, and foveal avascular zone area were evaluated at each follow-up visit. Changes in these parameters in the postoperative eye were tracked at each follow-up visit as were the relative differences between the postoperative eye and the contralateral eye.

RESULTS

Vascular density of parafoveal superficial capillary plexus and total retina demonstrated significant decrease in the postoperative silicone-filled eye when compared to the fellow eye (P < 0.0001). Although there was some improvement in these values at subsequent follow-ups, they remained less than the fellow eye. Foveal (P = 0.002) and parafoveal (P < 0.0001) thickness were less than the fellow eye. Choroidal flow area did not show a significant change in operated eye compared with the fellow eye.

CONCLUSION

Eyes with macula-off RRD repaired with PPV and SO, at 3-month follow-up, demonstrated less retinal vascular density at parafoveal area as well as lower retinal thickness at fovea when compared to the healthy fellow eyes.

Multimodal Imaging in Retinitis Pigmentosa: Correlations among Microvascular Changes, Macular Function and Retinal Structure

Purpose:

To analyze microvascular changes in patients with retinitis pigmentosa (RP) with relatively preserved visual acuity (VA), using swept source optical coherence tomography (SS-OCT) angiography to correlate results to macular function and structure.

Methods:

This was a case–control study conducted over 70 eyes of 35 RP patients with relatively preserved VA. All patients underwent a complete ophthalmic examination, including SS-OCT, OCT angiography (OCT-A), fundus autofluorescence (FAF), and multifocal electroretinogram (mfERG). Thirty-four eyes of 34 healthy controls of age-, sex-, and axial length-matched (control group), were also analyzed. The main outcome measures were foveal and parafoveal vascular densities (FVDs and PFVDs) in the superficial capillary plexus (SCP) and deep capillary plexus (DCP), foveal avascular zone (FAZ) and its enlargement coefficient and their correlation with macular function (by means of VA and mfERG), and structure (by means of FAF and SS-OCT).

Results:

In the RP group, PFVD was 25.99 ± 5.2% in the SCP and 34.47 ± 2.37% in the DCP and were significantly lower as compared to control group (P < 0.0001; P = 0.0026, respectively). Enlargement coefficient of FAZ was 1.78 ± 0.79. We found a statistically significant correlation between VA and PFVD in the DCP (P < 0.0001), FAZ disruption in the SCP (P = 0.006) and enlargement coefficient of FAZ (P = 0.01). The parafoveal DCP density was significantly correlated with P1 amplitude (P = 0.005) in rings 2, 3, 4, and 5 of the mfERG. We found a statistically significant correlation between parafoveal density in the DCP, thickness of ganglion cell complex (GCC) (P = 0.001), and the width of ellipsoid band (P = 0.041). Parafoveal SCP density was also correlated to GCC (P = 0.033).

Conclusions:

We showed that vascular alteration in RP begins at the level of the DCP, which affects the outer retina and leads to a narrowing of the ellipsoid. The alteration of the SCP would occur later in the evolution of the disease. Vascular changes occur early during RP and were highly correlated to retinal function and structure. OCT-A seems to be a good tool to quantify vascular network loss and could play a central role in staging, prognosis, and monitoring disease progression.

Relationship between vascular densities of choriocapillaris and the whole choroid using OCTA

PURPOSE

To study the vascular density (VD) of choriocapillaris and the whole choroid using optical coherence tomography-angiography (OCTA).

METHODS

Cross-sectional study enrolling healthy individuals between 18 and 35 years old and with an axial length (AL) lower than 26 mm, who were examined with swept-source OCTA Triton DRI (Topcon). Color pictures of both VD were obtained from a fovea-centered 6 × 6 mm macular exam, which were divided into 900 squares and codified into numbers.

RESULTS

A total of 50 patients (100 eyes) with a mean age of 27.29 ± 3.90 years and a mean AL of 23.67 ± 0.74 mm were analyzed. The highest choroidal VD was found in juxtapapillary macula, being followed by the most temporal macula and fovea. The lowest was found in superior and inferior perifoveal areas. The highest VD in choriocapillaris was in the fovea. VD in this layer was uniform, with a decrease from temporal toward nasal. Both VD differed and but correlated, especially in the fovea and in inferior-temporal macula.

CONCLUSION

VD of choriocapillaris and the whole choroid are not similar. The former is maximal in the fovea, and the latter is maximal in the juxtapapillary macula. In general lines, choroidal VD is higher than that of choriocapillaris. Both VD are directly correlated.

Ethnic differences in normal retinal capillary density and foveal avascular zone measurements

BACKGROUND

The purpose of this study was to quantify retinal capillary density and foveal avascular zone (FAZ) area in healthy subjects according to their ethnicity, using optical coherence tomography angiography (OCTA).

METHODS

In this cross-sectional study, all eyes underwent swept-source OCTA (Triton, Topcon, Tokyo, Japan). Macular OCTA scans (3 × 3 mm) were obtained in healthy white Caucasian and black African subjects. The FAZ area and capillary density in both the superficial (SCP) and deep capillary plexuses (DCP) were automatically measured using a custom-made software combining vessel binarization and skeletonization.

RESULTS

Twelve eyes of 12 healthy Caucasians and 15 eyes of 15 healthy black Africans were included in the analysis. The mean FAZ area was significantly smaller, and the overall vessel density (VD) was higher in the SCP and DCP of Caucasians compared to black Africans. The mean FAZ area was 0.26 ± 0.008 mm² in the SCP and 0.25 ± 0.05 mm² in the DCP in Caucasians versus 0.33 ± 0.08 mm² in the SCP (p = 0.01) and 0.37 ± 0.1 mm² in the DCP (p = 0.03) in Africans. In the SCP and DCP, the mean VD was, respectively, 40.5 ± 0.8% and 47.1 ± 0.5% in Caucasians versus 34.3 ± 1% (p = 0.008) and 40.6 ± 0.9% in Africans (p < 0.001).

DISCUSSION/CONCLUSION

In the SCP and DCP, VD is lower in black Africans compared to Caucasians. In OCTA studies on vascular diseases, ethnicity-matched measurements from healthy subjects should be used for comparisons.

The role of vascularization on changes in ligamentum flavum mechanical properties and development of hypertrophy in patients with lumbar spinal stenosis

BACKGROUND CONTEXT

Ligamentum flavum (LF) induced lumbar spinal stenosis (LSS) is conditioned not only by its "gathering" but especially by hypertrophy. Previous studies have examined the pathophysiology and biochemical changes that cause the hypertrophy. Some studies have described a link between chronic LF inflammation and neovascularization but others have reported highly hypovascular LF tissue in LSS patients. Currently, there is no practical application for our knowledge of the pathophysiology of the LF hypertrophy. Considerations for future treatment include influencing this hypertrophy at the level of tissue mediators, which may slow the development of LSS. To our knowledge, there is no study of micromechanical properties of native LF to date.

PURPOSE

(1) To clarify the changes in vascularization, chondroid metaplasia, and the presence of inflammatory cell infiltration in LF associated with LSS. (2) To quantify changes in the micromechanical properties associated with LF degenerative processes.

STUDY DESIGN/SETTING

Vascular density analysis of degenerated and healthy human LF combined with measurement of micromechanical properties.

METHODS

The study involved 35 patients who underwent surgery between November 1, 2015 and October 1, 2016. The LSS group consisted of 20 patients and the control group consisted of 15 patients. LF samples were obtained during the operation and were used for histopathological and nanoindentation examinations. Sample vascularization was examined as microvascular density (L_v), which was morphometrically evaluated using semiautomatic detection in conjunction with NIS-Elements AR image analysis software. Samples were also histologically examined for the presence of chondroid metaplasia and inflammation. Mechanical properties of native LF samples were analyzed using the Hysitron TI 950 TriboIndenter nanomechanical testing system.

RESULTS

Vascular density was significantly lower in the LSS group. However, after excluding the effect of age, the difference was not significant. There was high association between L_v and age. With each increasing year of age, L_v decreased by 11.5 mm². Vascular density decreased up to the age of 50. Over the age of 50, changes were no longer significant and L_v appeared to stabilize. No correlation was observed between L_v and the presence of inflammation or metaplasia; however, LSS patients had a significantly increased incidence of chondroid metaplasia and inflammatory signs. The mechanical properties of control group samples showed significantly higher stiffness than those samples obtained from the LSS group.

CONCLUSION

This study showed that L_v changes were not dependent on LSS but were age-dependent. Vascular density was found to decrease up to the age of 50. A significantly higher incidence of chondroid metaplasia and inflammation was observed in LSS patients. The mechanical property values measured by nanoindentation showed high microstructural heterogeneity of the tested ligaments. Our results showed that healthy ligaments were significantly stiffer than LSS ligaments.

CLINICAL SIGNIFICANCE

Prevention of the loss of LF vascularization during aging may influence stiffness of LF which in turn may slow down the LF degenerative processes and delay onset of LSS.