Mean Foveal Avascular Zone Research Articles

The Relationship of Serum Diabetes Antibodies With the Development of Early Diabetic Retinopathy Findings in Children With Type 1 Diabetes Mellitus

Purpose To explore how serum diabetes autoantibodies are related to the development of early diabetic retinopathy in children with type 1 diabetes mellitus. Methods In this prospective and observational study, 62 patients with type 1 diabetes mellitus who had not yet developed clinical diabetic retinopathy were followed up for at least 5 years. Healthy volunteers aged 10 to 20 years were also included. Insulin, pancreatic islet cells, and glutamic acid decarboxylase (GAD) autoantibodies were measured with an RIA kit at the time of type 1 diabetes mellitus diagnosis. Optical coherence tomography angiography (OCTA) was used to evaluate the foveal avascular zone (FAZ) and parafoveal vascular density (PVD) for the development of early diabetic retinopathy among the groups. Patients' OCTA findings were compared with those of healthy volunteers. The obtained data were analyzed via IBM SPSS Statistics for Windows, version 27.0. Spearman's rank correlation test and regression analysis were performed to determine independent predictors of OCTA and type 1 diabetes mellitus parameters. Results Eighteen boys and 44 girls with type 1 diabetes mellitus with a median age of 15.6 years (range: 10.08 to 20.88 years) were evaluated. Healthy control participants with a median age of 15.3 years (range: 14.2 to 18.2 years) were also included. The mean FAZ was greater in the type 1 diabetes mellitus group than in the healthy control group ( P = .013 and .119, respectively). The mean PVD was significantly lower in the type 1 diabetes mellitus group than in the healthy control group. There was no significant correlation between serum diabetes autoantibodies (GAD and insulin autoantibodies) and FAZ or PVD (FAZ and GAD; r = 0.138, P = .286, FAZ and anti-insulin; r = 0.100, P = .441, PVD and GAD; r = −0.151, P = .24, PVD and anti-insulin; r = −0.087, P = .499). Conclusions Type 1 diabetes mellitus in children without clinically detectable diabetic retinopathy is associated with impaired retinal microcirculation and irregularities at the FAZ margin. Impaired retinal microcirculation and irregularities were associated with glycated hemoglobin levels in the study group. Thus, studies with larger patient series are needed. [ J Pediatr Ophthalmol Strabismus . 20XX;X(X):XXX–XXX.]

Internal Limiting Membrane Peeling for Large Macular Holes Induces Only Structural Remodeling without Functional Impairment Over 12 Years

To evaluate the very long-term functional and structural outcomes of internal limiting membrane (ILM) peeling for full-thickness macular holes (FTMH). Observational case series nested within a multicenter, randomized, controlled clinical trial (RCT) (ClinicalTrials.gov: NCT00190190). Patients who underwent vitrectomy with or without ILM peeling for an idiopathic large FTMH in a tertiary ophthalmology center, with a minimum follow-up of 10 years after surgery. Review of charts, spectral-domain OCT (SD-OCT) scans, OCT angiography (OCTA) scans, and microperimetry of patients originally enrolled in the RCT. Primary outcome was functional assessment in both groups (ILM peeling or not) including the retinal sensitivity (RS), distance and near best-corrected visual acuity (BCVA), and number of eyes achieving ≥0.3 logarithm of the minimum angle of resolution >10 years after surgery. Secondary outcomes were structural assessment in the entire 3× 3-mm and 6× 6-mm areas, and regionally in the different areas of the ETDRS grid: OCT and OCTA biomarkers in both groups and fellow eyes. Thirteen eyes of 13 patients with a mean follow-up of 12 ± 0.73 years were included. The mean RS and BCVA, or visual improvement did not differ between ILM peeling (n= 8) and no peeling (n= 5) (all P > 0.05). The dissociated optic nerve fiber layers on en face OCT were only observed in eyes with ILM peeling, predominantly in temporal parafoveal (20%) and perifoveal (19%) rings. The mean total retinal thickness and inner retinal thickness in the parafoveal ring were significantly lower in peeled eyes (309 ± 11 μm and 94 ± 9 μm respectively) versus nonpeeled eyes (330 ± 21 μm and 108 ± 11 μm respectively; P= 0.037 and P= 0.040), without significant difference in ganglion cell or retinal nerve fiber layers. Accordingly, the mean superficial capillary plexus density in the parafoveal ring was significantly lower in eyes with peeling versus without (39.65 ± 3.76 % versus 47.22 ± 4.00; P= 0.005). The mean foveal avascular zone area was smaller in eyes with peeling versus without (0.24 ± 0.05 mm2 vs. 0.42 ± 0.13 mm2, respectively, P= 0.005). Despite persistent structural changes especially in the parafoveal ring, ILM peeling for idiopathic large FTMH did not seem to impact long-term RS or BCVA over 12 years. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Investigation of factors that may affect the foveal avascular zone: An optical coherence tomography angiography study

SIGNIFICANCE An understanding of factors that affect the foveal avascular zone (FAZ) in healthy eyes may aid in the early identification of patients at risk of retinal pathology, thereby allowing better management and preventive measures to be implemented. PURPOSE The size and shape of the FAZ can change due to retinal diseases associated with oxidative stress, including diabetic retinopathy, glaucoma, and macular degeneration. This study aimed to assess the relationship, if any, between factors that may affect the superficial FAZ (i.e., vessel density, vessel perfusion, overweight/obesity) and possible links with macular pigment optical density in young, healthy participants. METHODS One hundred thirty-nine participants aged 18 to 35 years were recruited to this cross-sectional study. The superficial FAZ area, foveal vascularity, and central macular thickness (CMT) were assessed using the Cirrus 5000. Health parameters, body mass index, trunk fat %, and macular pigment were analyzed to determine possible associations with the superficial FAZ. RESULTS Mean FAZ area was 0.23 ± 0.08 mm2. Females had a significantly larger mean FAZ area than males (p=0.002). The FAZ area was positively correlated with body mass index (Pearson's r = 0.189, p=0.026). Significant correlates of the FAZ area in the multivariate model included vessel perfusion (central), CMT, and trunk fat %, collectively explaining 65.1% of the overall variability. CONCLUSIONS Study findings suggest that reduced vessel perfusion, thinner CMT, and higher trunk fat % are plausible predictors of a larger FAZ area in healthy Caucasian adults. Low macular pigment optical density was, however, not associated with increased FAZ size in young healthy eyes. Noninvasive optical coherence tomography angiography testing, in association with these predictors, may aid in the early detection and monitoring of retinal diseases associated with oxidative stress.

Dark Adaptometry and Optical Coherence Tomography Angiography in Huntington Disease.

Huntington's Disease (HD) is a fully penetrant neurodegenerative disease leading to cognitive and motor disturbances. The retina may serve as a structural and functional extension of the central nervous system to identify biomarkers of HD using noninvasive imaging technology such as optical coherence tomography angiography (OCTA) and dark adaptometry. This case-control study included 12 HD participants (24 eyes) recruited from the Huntington's Disease Society of America Center of Excellence at Washington University in St. Louis along with 16 control participants (31 eyes). Disease-positive participants underwent imaging testing of retinal capillary density and foveal avascular zone utilizing OCTA along with dark adaptometry testing. Data were collected from November 2020 to February 2022. Individuals with HD had a lower mean age-adjusted superficial foveal capillary density and a higher mean deep foveal capillary density compared to control subjects. There was no significant difference in the mean foveal avascular zone or in dark adaptometry testing between the two groups. This study suggests that changes in retinal biomarkers may exist in patients with HD and that additional investigations using multimodal techniques are warranted.

Evaluation of Optical Coherence Tomography Angiography in Degenerative and Tractional Lamellar Macular Hole.

This study aims to evaluate the optical coherence tomography angiography (OCTA) findings in cases with degenerative and tractional lamellar macular holes (LMH). Two subtypes of LMH cases were included. Seventeen patients had the degenerative subtype, whereas 18 patients had the tractional subtype of LMH. Twenty healthy individuals were enrolled as the control group. The foveal avascular zone (FAZ) and retinal vascular densities in the superficial, deep capillary, and choriocapillary plexuses were analyzed and compared with fellow eyes and healthy controls using OCTA. The mean FAZ area was wider in the degenerative subtype (0.33 ± 0.14 mm2) compared to the tractional subtype (0.24 ± 0.10 mm2) (p=0.04) and control eyes (0.26 ± 0.10 mm2) (p=0.03). Foveal vessel densities in the superficial and deep capillary plexuses were lower in the degenerative group than in the tractional group, (21.7 ± 9.8% vs. 26.8 ± 6.9%, p=0.01 and 28.5 ± 5.1% vs. 36.9 ± 6.2%, p=0.01). Choriocapillary vascular density in the parafoveal area was also lower in degenerative lamellar macular holes compared to the tractional group (60.4 ± 4.7% vs. 63.7 ± 3.9%, p=0.03). Compared to control eyes, eyes with degenerative and tractional LMH showed lower vessel densities in the parafoveal and perifoveal areas of the SCP, DCP, and all layers of CC (p < 0.05). In the foveal area, the LMH groups showed higher foveal vascular density (FVD) in the SCP than control eyes, while in the DCP, FVD was lower in the degenerative LMH eyes relative to the other groups. The finding of microvascular changes between degenerative and tractional LMH subtypes highlights their distinct pathologies and supports recent changes in the classification and terminology of this macular condition.

A cross-sectional study of macular displacement after macular hole surgery with ILM peeling in patients with idiopathic macular hole.

To examine the retinal displacement and change in mean superficial foveal avascular zone (FAZ) after successful closure of macular hole (MH) with vitrectomy with internal limiting membrane peeling (ILM) and gas tamponade. A total of 45 patients with idiopathic MH who underwent 23G pars plana vitrectomy with ILM peeling and tamponade with 20% SF6/14% C3F8 were included. Follow-up visits were performed at 2, 4, and 8 weeks. OCT and OCT-A scans were performed along with detailed ocular examination. Distance between optic disc and an easily identifiable vascular bifurcation nasal and temporal to fovea, FAZ, was noted. Chi-square test (categorical data) and Mann-Whitney U test and t tests for other parameters were performed for statistical analysis. The mean displacement (µm) of an easily identifiable vascular bifurcation in the nasal quadrant was 96.58 ± 36.55 at 8 weeks and in the temporal quadrant was 273.07 ± 85.51 at 8 weeks. The change was statistically significant in the temporal quadrant (P = <0.001). The mean BCVA changed from a minimum of 0.08 at the preoperative timepoint to a maximum of 0.23 at 8 weeks (P = <0.001). The mean FAZ area (mm²) decreased from a maximum of 0.37 at the preoperative timepoint to a minimum of 0.19 at 8 weeks (p = <0.001). The retina in the temporal quadrant is displaced significantly more than nasal quadrant after successful closure of macular hole. The mean superficial FAZ also decreases suggesting a centripetal movement of the foveal tissue postoperatively.

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

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). This cross-sectional study included 100eyes of 100patients 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. 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. 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.

LONGITUDINAL ANALYSIS OF MICROVASCULAR CHANGES IN SICKLE CELL DISEASE USING SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

To analyze the changes in macular vascular densities (VDs) and foveal avascular zone (FAZ) over a 6-year period using swept-source optical coherence tomography angiography in patients with sickle cell disease compared with unaffected control subjects. Thirty eyes of patients with sickle cell disease and 12 eyes of unaffected control subjects matched for age and ethnicity were examined at a 6-year interval using the same imaging protocol, including ultra-wide-field angiography, swept-source OCT, and 3 × 3-mm optical coherence tomography angiography. The macular VD and FAZ were measured on ImageJ software according to previously reported algorithms. In sickle cell eyes, the mean FAZ significantly increased ( P < 0.01), and the VD decreased in the foveal (within a circle of 1.5 mm in diameter around the foveal center) and temporal areas in both the superficial and the deep capillary plexuses ( P < 0.01). The VD did not change over time in the parafoveal area (annulus between two circles of 1.5 and 3 mm in diameter) and in the superior, inferior, and nasal sectors. No worsening of peripheral retinopathy was observed in the cohort during the follow-up, except for one eye that developed sea-fan. In the control eyes, no microvascular change was observed over time in FAZ size and VD. These longitudinal optical coherence tomography angiography findings in patients with sickle cell disease showed an enlargement of the FAZ and a decrease in VD in the temporal and perifoveal regions despite the absence of progression of peripheral retinopathy, suggesting a worsening of the macular nonperfusion over time in sickle cell disease.

Multimodal Structural and Functional Characterization of Retinal Vasculopathy with Cerebral Leukoencephalopathy

ObjectiveTo describe and quantify the structural and functional consequences of retinal vasculopathy and cerebral leukoencephalopathy (RVCL) on the neurosensory retina. DesignCross-sectional descriptive study from December 2021 to December 2022 ParticipantsRVCL patients (n=9, 18 eyes) recruited from the RVCL Research Center at Washington University in St. Louis MethodsRVCL patients underwent comprehensive ophthalmological evaluation including Optical Coherence Tomography (OCT), Optical Coherence Tomography Angiography (OCT-A), ultra-wide-field (UWF) fundus imaging, retinal autofluorescence, dark adaptation, electroretinography (ERG), Goldmann kinetic perimetry, and fluorescein angiography (FA). Main Outcomes MeasuresComprehensive characterization from various modalities including: best corrected visual acuity, central subfield thickness (μm) from OCT, foveal avascular zone (mm2) from OCT-A, dark adaptation rod intercept (sec), cone response in ERG, and presence or absence of vascular abnormalities, leakage, neovascularization, and nonperfusion on FA. ResultsA total of 18 eyes from 9 individuals were included in this study. The best-corrected visual acuity ranged from 20/15 to 20/70. The mean central subfield thickness from OCT was 275.8 μm (range 217-488 μm). The mean foveal avascular zone (FAZ) from OCT-A was 0.65 mm2 (range 0.18-1.76 mm2). On dark adaptometry, the mean time was 5.02 minutes (range 2.9 - 6.5 min) with 1 individual with impaired dark adaptation. ERG demonstrated mild cone response impairment in 4 eyes. On FA, there was evidence of macular and peripheral capillary non-perfusion in 16 of 18 eyes and notable areas of vascular leakage and retinal edema in 5 of the 18 eyes. ConclusionsThis study illustrates the phenotypic spectrum of disease and may be clinically valuable for aiding diagnosis, monitoring disease progression, and further elucidating the pathophysiology of RVCL to aid in the development of therapies.

Comparative study between fundus fluorescein angiography and optical coherence tomography angiography in evaluation of diabetic maculopathy

Background Diabetic maculopathy is a serious consequence of diabetic retinopathy (DR) that greatly affects the visual acuity. Diabetic macular edema (DME) and diabetic macular ischemia (DMI) are major causes of vision affection in diabetic patients. Purpose The aim of this study was to compare fluorescein angiography (FA) and optical coherence tomography angiography (OCTA) in evaluation of diabetic maculopathy. Patients and methods This comparative cross-sectional study was performed on 87 eyes of 54 patients with type I or type II diabetes, older than 18 years old with any diabetic retinal changes, and 108 eyes of 54 control subjects. An ocular examination was performed as well as color fundus photography, FA, and OCTA. Investigations were done on the same day. FA and OCTA findings were summarized and compared. Results The mean age of the patients was 59.4±8.5 years. OCTA was statistically significantly superior to FA in diagnosing DMI. The foveal avascular zone (FAZ) was ischemic (enlarged) in 74 (85.06%) eyes by OCTA compared with only 46 (52.87%) eyes by FA, with a statistically significant difference (P = 0.001). In addition, OCTA detected microaneurysms significantly more than FA (P = 0.001). The mean FAZ area of the control eyes by OCTA was significantly less than in the ischemic eyes (U = 56.602, P &lt; 0.001), while the superficial capillary plexus (SCP) vascular density (VD) and the deep capillary plexus (DCP) VD in the control eyes was statistically significantly higher than in the ischemic eyes (U = 36.984, P &lt; 0.001, and U = 35.955, P &lt; 0.001, respectively). FA showed diffuse leakage (edema) at the macula as the most common pattern of DME that was detected in 37.9% of the eyes followed by focal macular leakage in 18.4% of the eyes and cystoid leakage in 8% of the eyes while 35.5% of the eyes showed no macular edema. Conclusion OCTA is a cornerstone in DMI diagnosis both qualitatively and quantitatively. In addition, it is essential in evaluating the deep retinal vasculature, while FA is essential in diabetic retinopathy grading and in the diagnosis of DME in a qualitative manner. Both investigations are complementary to each other in diabetic maculopathy evaluation.

Evaluation of childhood developing via optical coherence tomography-angiography in Qamdo, Tibet, China: A prospective cross-sectional, school-based study.

Optical coherence tomography angiography (OCTA) is a new and reliable machine used to evaluate retinal structure and macular perfusion in children. The use of OCTA under bad condition such as high altitude, low atmospheric oxygen, and low humidity, in children is rarely. To quantify the macular micro-vasculature in healthy children of various ages using OCTA in Qamdo. Design: Prospective cross-sectional, school-based study. Three hundred and forty-seven normal students from 9 schools in 4 different areas in Qamdo were included. OCTA was performed on a 3 mm × 3 mm area centered on the macular region and macular cube 512 × 128 showed details in macular. Early treatment of diabetic retinopathy study Vessel Flow Density (VD) of the macular central vascular plexus density (CVD), inner vascular plexus density (IVD), full vascular plexus density (FVD), and the size of the foveal avascular zone (FAZ) were measured. All these results corrected by t/s = 3.382 × 0.01306 × (axial length-1.82). The differences were compared among various ages, sexes and living environments. The mean FAZ area in all eyes was 0.27 mm2 ± 0.12 mm2. The mean foveal thickness (MFT) in the macular cube was 227.64 μm ± 23.51 μm. Compared with girls, boys had a lager FAZ (P = 0.0029). Among the different age groups, MFT (P < 0.001) and FVD (P < 0.0001), IVD (P < 0.0001), and CVD (P = 0.0050) increased with age. FAZ areas were not correlated with age (P = 0.8853) or others (MFT, area). OCTA can use to evaluate macular perfusion in children. Our data bridge the gap between structural OCT and perfusion density in children in high altitude. Even though these were not a longitudinal study, it may provide us with hints about retina development during puberty and clinical implications of OCTA in children.

Retinal and choroidal microvasculature in early and three months post COVID-19: A case-control study

To compare the retinal vascular density (VD), choroidal vascularity index (CVI), and choroidal thickness (CHT) between patients infected with COVID-19 and healthy subjects using non-invasive optical coherence tomography angiography (OCTA) and enhanced depth imaging OCT (EDI-OCT) technique.This case-control study was carried out on patients with COVID-19 and healthy controls. Patients’ data were acquired immediately after active infection and three months later. The diagnosis was based on clinical symptoms and a positive PCR test. VDs in superficial and deep capillary plexuses (SCP and DCP) and CHT and CVI were measured and compared between groups. A total of 160 eyes from 80 patients (55% female, mean age 51 ± 13 years) and 80 controls (55% female, mean age 49 ± 12 years) were enrolled. In acute phase infection, the mean foveal avascular zone (FAZ) area was 0.28 ± 0.06 mm2 and 0.22 ± 0.05 mm2 in patient and control groups, respectively (P < 0.001). CVI was 61.06 ± 2.59 µm and 72.28 ± 3.84 µm in patients and control groups, respectively (P < 0.001). After three months, the mean FAZ area was 0.28 ± 0.06 mm2 and 0.23 ± 0.05 mm2 in the patient and control groups, respectively (P < 0.001). CVI was 60.93 ± 2.11 µm and 72.46 ± 3.80 µm in patients and control groups, respectively (P < 0.001). Subfoveal CHT was not significantly different between groups (P = 0.69). SCP and DCP VDs were significantly less in the patients’ group (P < 0.001). In the patients’ group, the VDs in the DCP of the whole images and parafoveal DCP (P < 0.001) were reduced significantly after three months in comparison to the acute phase, while the FAZ area, subfoveal CHT, and CVI were not significantly different.COVID-19 infection may be associated with acute and long-term changes of VDs in the retinal and choroidal vasculature without significant effect on the subfoveal CHT.

Evaluation of Automated Measurement of Macular Ischemic Changes in Retinal Vein Occlusion With Optical Coherence Tomography Angiography.

The foveal avascular zone (FAZ) is altered in patients with retinal vein occlusion (RVO) and correlates inversely with visual acuity. Optical coherence tomography angiography (OCTA) is an imaging tool to visualize FAZ safely and easily. Automated measurements can facilitate interpretation of OCTA images. In this comparative cross-sectional study, we compare the results of manual measurement of the FAZ with automated measurement by built-in application (Metrix). The study included patients with RVO who underwent OCTA. Manual measurement was compared with automated evaluation by Metrix in 3 mm x 3 mm and 6 mm x 6 mm scan sizes and correlations of the circularity, circumference, and size of the FAZ were calculated. Forty-seven eyes were included in the study. A reliable measurement result in both Metrix 3 mm x 3 mm and 6 mm x 6 mm was found in only 25 of 47 eyes. The mean FAZ in these eyes by manual measurement was 0.50 mm2 compared with 0.20 mm2 and 0.24 mm2, respectively, by automated measurement. A statistically significant inverse correlation was found in both the automated 3 mm x 3 mm and 6 mm x 6 mm measurements for FAZ circumference with FAZ circularity but not FAZ area. The two automated measurements showed no significant bias regarding the size of the FAZ, but the plausibility of the data should be checked on a case-by-case basis. The manual measurements were higher, indicating limited agreement of manual and automated measurements. The information on circularity can point to ischemic maculopathy early in the course of the disease. [Ophthalmic Surg Lasers Imaging Retina 2023;54:462-469.].

In vivo evaluation of macular microvasculature in childhood malnutrition using optical coherence tomography angiography.

To evaluate the microvascular alterations and foveal avascular zone (FAZ) changes in the foveal and parafoveal region in malnourished children. This cross-sectional study analyzed 168 eyes of 85 patients. The subjects were split into 3 groups based on their body mass index (BMI) percentiles and defined as Group 1 (BMI percentiles ≥95th, overnutrition group), Group 2 (BMI <5th percentile, undernutrition group) and Group 3 (BMI ≥5th and <85th percentile, control group). All subjects were examined with optical coherence tomography angiography (OCTA) to evaluate superficial capillary plexus (SCP), deep capillary plexus (DCP) vessel density (VD) and FAZ parameters. The retinal nerve fiber layer (RNFL), average macular ganglion cell-inner plexiform layer (GCL-IPL), inner limiting membrane-retinal pigment epithelium(ILM-RPE) thickness were evaluated using SD-OCT device. Age and gender did not statistically differ across groups (p=0.12 and p=0.92). Groups 1 and 2 were found to have significantly higher VD of the superior-hemisphere of the DCP levels than the control group (p=0.001). The control group's foveal VD of SCP was statistically higher than group 1's (p=0.012). Parafoveal VD was significantly increased in the superior of the SCP of group 1 and the lower hemisphere of the SCP of group 2 compared with the control group (p=0.02 and p=0.02, respectively). The mean FAZ perimeter, choriocapillaris flow area, RNFL, GCL-IPL and ILM-RPE thickness were similar between all groups. The childhood undernutrition and overnutrition may affect the density of retinal capillaries. Although the FAZ area and choriocapillary flow did not change, retinal capillary density tended to increase in malnutrition.

Microvasculature evaluation of anisometropic amblyopia children by Angio-OCT

To compare and assess the choroidal and retinal microstructural vascularity in amblyopic eyes with the fellow eyes in anisometropic amblyopic children using angiography optical coherence tomography (Angio-OCT). Twenty-seven children (54 eyes; 5.59 ± 1.08 years old; 59.3% girls) were enrolled in this study. Choroidal thickness (CT) was measured with the use of the enhanced depth imaging mode in Angio-OCT. Parafoveal/peripapillary vascular density indices and the foveal avascular zone (FAZ) size were analyzed by MATLAB code programming on Angio-OCT images. The mean FAZ size of the amblyopic eyes were larger both in superficial and deep capillary plexus layer (SCPL/DCPL). Compared with the contralateral eyes (BCVA were normal), all the vascular density indices of SCPL and DCPL in the parafoveal and peripapillary zones were lower in the amblyopic eyes, however, the difference was insignificant (p > 0.05). No significant decrease was observed in four quadrants analyses of the amblyopic eyes (p > 0.05). Except for the measurement at 2000 µm and 1500 µm from the fovea in temple, CT in amblyopic eyes were significantly thicken than the fellow eyes (p < 0.05). Compared with the fellow eyes, the CT of certain areas were thicker in the amblyopic eyes. Though the FAZ size of the amblyopic eyes was larger in SCPL/DCPL layers, the retinal vascular density indices in SCPL/DCPL were lower in amblyopia eyes without statistical difference. Angio-OCT may be an effective way to evaluate the status of the choroidal and retinal vascular system in amblyopic children.

Optical coherence tomography-based assessment of macular vessel density, retinal layer metrics and sub-foveal choroidal thickness in COVID-19 recovered patients.

The primary objective of the study was to assess the macular retinal vessel density, subfoveal choroidal thickness, and retinal layer metrics by optical coherence tomography angiography (OCTA), enhanced-depth imaging optical coherence tomography (EDI-OCT), and spectral domain optical coherence tomography (SD-OCT), respectively, in recovered COVID-19 patients and its comparison with the same in control subjects. The secondary objective was to evaluate differences in OCTA parameters in relation with the severity of COVID-19 disease and administration of corticosteroids. A case-control study was performed that included patients who had recovered from COVID-19 and age-matched healthy controls. Complete ocular examination including OCTA, SD-OCT, and EDI-OCT were performed three months following the diagnosis. Three hundred sixty eyes of 180 subjects were enrolled between the two groups. A decreased mean foveal avascular zone area in both superficial capillary plexuses (P = 0.03) and deep capillary plexuses (P < 0.01), reduced average ganglion cell layer-inner plexiform layer thickness (P = 0.04), and increased subfoveal choroidal thickness (P < 0.001) were observed among cases in comparison to the control group. A significant correlation was found between sectoral macular vessel density in relation to disease severity and a decrease in vessel density with greater severity of the disease. OCTA detected retinal microvascular alterations following SARS-CoV-2 infection in subjects with the absence of any clinical ocular manifestation or systemic thrombotic events. These parameters could be used to help identify patients with a higher incidence of systemic thromboembolism on longer follow-ups and identify the impact of corticosteroids on retinal architecture.

Optical Coherence Tomography Angiography in Diabetic Macular Edema Treated with Intravitreal Aflibercept: A 48-Week Observational Study (the DOCTA Study)

Introduction: Central vision loss due to diabetic macular edema (DME) is related to the macular edema itself but also, in some cases, to alterations of the foveal avascular zone (FAZ). The aim of this trial was to study changes in macular vessels in eyes with DME treated with aflibercept using optical coherence tomography angiography (OCTA). Methods: This was a longitudinal, prospective, noncontrolled, single-arm study. The primary objective was the quantitative assessment of macular vessels over time in patients with DME treated with intravitreal aflibercept during a 48-week follow-up using OCTA. Results: Twenty-six DME eyes from 26 patients were included (mean age, 64.6 years; women, 53.8%; prior anti-VEGF treatment, 46.1%). Each eye received a mean (SD) of 7.2 (2.2) injections. The following parameters of the FAZ did not change during the 48-week follow-up: the mean (SD) FAZ area varied from 0.19 (0.19) mm² at baseline (n = 22) to 0.23 (0.20) mm² at week 48 (n = 15), boundary from 1.54 (1.21) to 2.04 (1.20) mm, and circularity from 0.45 (0.33)% to 0.57 (0.20)%. There was no change in perfusion density and vessel density of the macula in the 3-mm circle. As expected, mean central retinal thickness, macular volume, and visual acuity improved during follow-up. Conclusion: No change in macular perfusion was observed in eyes with DME during a 48-week follow-up after intravitreal injections of aflibercept. Randomized controlled trials using OCT angiography in large populations with extended observation periods are needed to assess changes in macular vessels after intravitreal anti-VEGF treatment.

Association Between Optical Coherence Tomography Angiography Findings and Inner Retinal Thickness in Diabetic Patients.

To investigate the association between optical coherence tomography angiography (OCTA) findings and inner retinal thickness (IRT) in diabetic patients. This retrospective study included 23 eyes of 23 diabetic patients with retinopathy (group 1), 30 eyes of 30 diabetic patients without retinopathy (group 2), and 27 eyes of 27 non-diabetic age-matched controls (group 3). Foveal avascular zone (FAZ) area (mm²), average vessel density (%) in the parafoveal region, and average IRT in the parafoveal region (μm) were calculated using 6x6 mm OCTA images. Correlations between IRT and OCTA findings were analyzed. The mean FAZ area was 0.32±0.11 mm² in group 1, 0.29±0.08 mm² in group 2, and 0.22±0.09 mm² in group 3. There were statistically significant differences between groups 1 and 3 (p&lt;0.001) and between groups 2 and 3 (p=0.001). Average IRT was 108.02±9.42 µm in group 1, 110.12±11.01 µm in group 2, and 114.41±5.21 µm in group 3, with statistically significant differences between groups 1 and 3 (p=0.003) and between groups 2 and 3 (p=0.014). In both group 1 and group 2, average IRT was correlated with FAZ area (r=-0.320 and -0.512, respectively). The inner retina is significantly thinner in diabetic patients with and without retinopathy compared to controls. Quantitative OCTA findings and IRT are correlated in diabetic patients, suggesting that both structures are compromised in patients with diabetes with or without retinopathy. Microvascular changes in FAZ detected by OCTA might precede neurodegenerative changes.

Reproducibility and Reliability of Spectralis II OCT Angiography Vascular Measurements.

Purpose: to investigate the reproducibility and reliability of OCT-A vascular measurements using Heidelberg Spectralis II OCT-A. Methods: a prospective study involving a single eye of patients aged 18 or older with no ocular disease. In order to investigate the reliability of the first and second OCT-A scans, the coefficient of variation of the foveal avascular zone (FAZ) and the vessel density (VD) in the superficial (SCP), intermediate (ICP) and deep capillary plexus (DCP) were calculated. Results: A total of 75 eyes were included in the study. The mean FAZ in the first and second scan was 0.36 × 0.13 mm2 and 0.37 × 0.12 mm2, respectively, in the SCP, 0.23 × 0.10 mm2 and 0.23 × 0.09 mm2 in the ICP, and 0.42 × 0.11 mm2 and 0.43 × 0.12 mm2 in the DCP. The overall VD was 36.05 × 9.01 and 35.33 × 9.92 at the first and second scan, respectively, in the SCP, 21.87 × 5.00 and 21.32 × 5.56 in the ICP, and 23.84 × 6.53 and 23.20 × 6.83 in the DCP. No statistically significant differences in FAZ measurements and VD in all sectors of each capillary plexus were observed between the first and second scan (p > 0.05). Conclusion: our study demonstrated the good reproducibility and reliability of OCT-A vascular measurements in the analysis of the FAZ and the quantification of VD in each capillary plexus of the retina.

Evaluating the Quantitative Foveal Avascular Zone and Retino-Choroidal Vessel Density Using Optical Coherence Tomography Angiography in a Healthy Indian Population.

Objective: The foveal avascular zone (FAZ) is the round capillary-free zone within the macula and is supplied only by a single-layered parafoveal capillary arcade. This study aimed to evaluate the quantitative FAZ and retino-choroidal vessel density (VD) using optical coherence tomography angiography (OCTA) in a healthy Indian population.Methods: This was a cross-sectional observational study that was conducted for evaluating the quantitative FAZ and retino-choroidal VD of 200 eyes of 100 healthy Indian subjects, including 62 males and 38 females (age range 17-50 years) having the best-corrected visual acuity (BCVA) of logMAR 0 (20/20; 6/6) and spherical equivalent refractive error of not more than 1 D. The subjects were examined using OCTA automated software on spectral-domain OCT (SD-OCT; Nidek RS 3000 Advance 2; Nidek, Inc., Fremont, CA) on a 3 x 3 mm OCTA macular scan centred on the fovea. The FAZ size, perimeter and circularity index, VD in superficial, deep, and outer retina (OR), outer retinal chorio-capillaries (ORCC), chorio-capillaries (CC) and choroid (C) were analysed in the circular and quadrant-segmented zones. A correlation was found between the FAZ size, perimeter and circularity, and VD in retino-choroidal layers, and between BCVA, age, central foveal thickness (CFT) and sub-foveal choroidal thickness (SFCT), and OCTA parameters.Results: The FAZ and surrounding vascular arcades were intact in all eyes, showing either a vertical or horizontal oval-shaped symmetrical formation without gaps, holes or interruption of the capillary network. The mean value of CFT was 237.5±26.0 microns and SFCT was 269.6±53.0 microns. The mean FAZ area was 0.42±0.23 mm2, FAZ perimeter was 3.3±1.0 mm and FAZ circularity index was 0.46±0.1. The mean VD in superficial capillary plexus (SCP) was 23.87±10.66, in deep capillary plexus (DCP) was 16.03±9.90, in OR was 13.22± 12.27, in ORCC was 39.74±14.32, in CC was 37.02±16.43 and in choroid was 37.43±16.76. The increasing order of VD in different retino-choroidal layers was OR<DCP<SCP<CC<C<ORCC. The FAZ area and perimeter had a statistically significant (SS) negative correlation with the VD in SCP, DCP and OR, while the FAZ perimeter additionally had a SS negative correlation with the VD in the choroid. The FAZ circularity had a SS positive correlation with VD in SCP, DCP and OR. There was no SS correlation between the age of subjects and OCTA parameters. The BCVA had a SS correlation with only one parameter, i.e. ORCC foveal (r=-0.15; p=0.03). There was a SS negative correlation between CFT and FAZ area and perimeter, and a SS positive correlation between the CFT and VD in SCP, DCP and OR. There was a SS positive correlation between the SFCT and VD in different layers including SCP, DCP, ORCC, CC and choroid.Conclusions: VD is the highest in the ORCC and lowest in the OR segment. A better VD in SCP, DCP and OR is associated with a reduced FAZ area/FAZ perimeter and an increased FAZ circularity index. A lower VD in the ORCC is associated with worse BCVA. In a healthy subject, a relatively thicker foveal region is likely to have better vascularity of SCP, DCP and OR and a smaller FAZ area/FAZ perimeter. In the absence of diseases, relatively thicker sub-foveal choroid is expected to have better vascularity of SCP, DCP, ORCC, CC and choroid.