Foveal Avascular Zone Perimeter Research Articles

Race/Ethnicity Analysis of Vascular Alterations in Optical Coherence Tomography Angiography in Diabetic Patients

ABSTRACT Purpose Racial and ethnic minorities have a higher prevalence of diabetic retinopathy (DR) and present at advanced stages of disease. In an urban hospital population, we investigated microvascular differences in optical coherence tomography angiography (OCTA) between racial/ethnic groups while adjusting for socioeconomic status (SES). Methods 3 × 3 mm2 macular OCTA scans were obtained for analysis of foveal avascular zone (FAZ) area, FAZ perimeter as well as superficial (SCP) and deep capillary plexus (DCP) vessel density (VD), vessel length density (VLD), and adjusted flow index (AFI). SES was measured using the Area Deprivation Index. Multivariable regression models were used to adjust estimates for relevant confounders. Results 217 non-diabetic and 1,809 diabetic patients were included in the study, consisting of 42.2% Hispanic, 24.9% non-Hispanic (NH) Asian, 6.8% NH Black, 9.7% NH White and 16.3% Other patients. NH White was used as the reference group. Hispanic, NH Asian, and NH Black patients had significantly greater FAZ areas and FAZ perimeters, and lower DCP VD and VLD, among both non-diabetic and diabetic patients (Benjamini-Hochberg adjusted P-values <0.05). The addition of SES scores in the models did not modify any regressions significantly. Conclusions In patients with and without diabetes, racial and ethnic minorities have significant retinal microvasculature differences when compared to NH White patients, regardless of SES. These differences are pronounced in DCP and may predispose racial/ethnic minorities to worse outcomes in DR, thus widening disparities in ophthalmic care.

Effect of hydroxychloroquine blood concentration on the efficacy and ocular toxicity of systemic lupus erythematosus.

In the absence of evidence-based guidance on the impact of hydroxychloroquine (HCQ) blood concentration on efficacy and ocular toxicity in systemic lupus erythematosus (SLE), the clinical monitoring of HCQ blood concentration is not yet widely performed, which raised concerns about the necessity of conducting HCQ blood concentration monitoring. In this retrospective study, we consecutively enrolled 135 patients with SLE who received HCQ treatment for more than 6months from July 2022 to December 2022. Ocular toxicity was evaluated by collecting relevant retinal parameters using optical coherence tomography angiography (OCTA). Therapeutic efficacy was evaluated using the SLE disease activity index (SLEDAI) and relevant clinical parameters. HCQ blood concentration was determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Spearman correlation analysis revealed that the cumulative dose of HCQ was positively correlated with the foveal avascular zone (FAZ) perimeter and FAZ area (r = 0.734, P < 0.001; r = 0.784, P < 0.001). Meanwhile, the treatment duration of HCQ was positively correlated with FAZ perimeter and FAZ area (r = 0.761, P < 0.001; r = 0.882, P < 0.001). The univariate and multivariate logistic regression analyses indicated that HCQ blood concentration was associated with the disease activity of patients with SLE (odds ratio 0.994, 95% CI 0.990-0.999). HCQ blood concentration may be an important factor in assessing the therapeutic effectiveness of SLE patients. The HCQ-related ocular toxicity was a long-term effect related to long term exposure, rather than the blood concentration of HCQ at the time of testing. More importantly, when addressing HCQ-related ocular toxicity, it may be crucial to pay attention to the cumulative dose and treatment duration of HCQ.

A classification of idiopathic epiretinal membrane based on foveal avascular zone area using optical coherence tomography angiography

Objective To evaluate the characteristics and prognoses of idiopathic macular epiretinal membrane (iERM) using a classification based on the foveal avascular zone (FAZ) area. Method IERMs were classified into four stages based on the FAZ area. Baseline FAZ-related parameters, pre-and postoperative central macular thickness (CMT), and best corrected visual acuity (BCVA) were observed and compared between different stages. The correlations of structural parameters with pre-and postoperative logMAR BCVA were analyzed. Results 162 iERM eyes were enrolled, including 105 eyes followed up for 12 months after surgery. The preoperative BCVA was better at the early stage. Postoperative BCVA at Stages 2 and 3 were better compared to Stage 4. The early stage was associated with thinner CMT pre-and postoperatively. However, there was no significant difference in CMT between postoperative Stages 1 and 2 or Stages 3 and 4. Preoperative logMAR BCVA was negatively correlated with FAZ area, perimeter, and FD-300 and was positively correlated with CMT and acircularity index (AI). CMT correlated positively with BCVA for each stage, except Stage 4; FAZ area, perimeter, and FD-300 had a negative correlation at Stage 1. Baseline BCVA and CMT positively correlated with BCVA at the last follow-up, while FAZ area and FD-300 were negatively correlated. Baseline BCVA had a positive correlation for each stage, except Stage 1; FD-300 had a negative correlation at Stages 2 and 3; CMT had a positive correlation at Stage 3. Conclusion A classification based on the FAZ area was established innovatively. This classification can reflect the progression of iERM and is helpful to the postoperative prognosis.

Clinical Features Related to OCT Angiography Artifacts in Patients with Diabetic Macular Edema

To investigate the frequency and type of artifacts on OCT angiography (OCTA) images and the relationship with clinical features in eyes with diabetic macular edema (DME). Retrospective, cross-sectional comparative study. One hundred ninety-two eyes of 140 patients with DME were included. Medical records, OCT and OCTA images (Spectralis), and ultrawidefield color fundus photographs (Optos plc) were evaluated. The frequency of artifact types (segmentation, motion, projection artifact, and low signal) was determined. The relationships between artifact types and clinical features such as best-corrected visual acuity (BCVA), mean central retinal thickness (CRT), foveal avascular zone (FAZ) area, perimeter, circularity index, perfusion density (PD), vessel density (VD), fractal dimension (FD) in the superficial capillary plexus, intermediate capillary plexus (ICP), and deep capillary plexus (DCP), flow voids (FVs) in the choriocapillaris, presence of hard exudate (HE), and cataract were determined. The mean age was 71.6 ± 11.4 years, and 86 (61.4%) out of 140 were men. Artifacts were present in 63 (32.8%) of 192 eyes. Twenty-nine (15.1%) eyes had segmentation artifacts, 12 (6.3%) had motion artifacts, 11 (5.7%) had projection artifacts, and 18 (9.4%) had low signal. Best-corrected visual acuity, PD, VD, and FD in ICP and DCP were significantly lower; and CRT, FAZ area and perimeter in ICP and DCP, and presence of cystoid macular edema, HE, and cataract were higher in eyes with artifacts versus eyes without artifacts (P < 0.05 for each). Multivariate linear regression analysis showed a significant association between segmentation artifacts and decreased BCVA (odds ratio [OR],5.277; P= 0.02), increased CRT (OR, 1.015; P < 0.001), increased area of FAZ in DCP (OR, 6.625; P= 0.02), and increased perimeter of FAZ in DCP (OR, 1.775; P < 0.04); there was also a significant association between projection artifacts and presence of HE (OR, 2.017; P= 0.02) and between motion artifacts and presence of cataract (OR, 4.102; P= 0.01). OCT angiography artifacts were present in one third of DME eyes, with segmentation artifacts being the most frequent type. Determining OCTA artifacts is crucial to ensure accurate clinical evaluation. These data could help in developing more standardized clinical protocols for image acquisition and interpretation used in clinical practice and research. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Detection of Retinal Microvascular Changes with Optical Coherence Tomography Angiography in Patients with Acute Leukemia Without Retinopathy.

Acute leukemia often affects microcirculation perfusion. This study aimed to investigate retinal microvascular changes in patients with acute leukemia without retinopathy during clinical remission using optical coherence tomography angiography (OCTA) and to determine the correlation of these changes with systemic laboratory values. Thirty-eight patients in remission from acute leukemia with no retinopathy (NLR group) and 36 age-matched healthy individuals (control group) were included in this cross-sectional study. OCTA parameters, including the central foveal thickness (CFT), foveal avascular zone (FAZ) area, FAZ perimeter, acircularity index (AI), foveal density (FD300), and the vessel densities (VDs) of the superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris were analyzed in a 6 × 6 mm2 macular scan. Correlation and multiple linear regression analyses were conducted to identify potential systemic characteristics associated with these OCTA metrics. AI (P = 0.034) and FD300 (P < 0.001) differed significantly between the NLR and control groups. The VD of SCP in the parafovea (P = 0.001) and of DCP in both the parafovea (P = 0.011) and perifovea (P = 0.001) were significantly lower in the NLR group than in the control group. In a multiple linear regression analysis, the reduced VD of the perifoveal DCP was significantly correlated with the increased international normalized ratio (standardized beta [STD β] = - 0.356; P = 0.047). Macular microvascular changes can be observed during remission from acute leukemia antecedent to clinically visible retinal lesions. Hematological disturbances may be associated with microvascular impairments in preclinical leukemic retinopathy.

Quantitative microvascular analysis in different stages of retinitis pigmentosa using optical coherence tomography angiography

As retinitis pigmentosa (RP) is chronic and progressive, the chronological sequence of microvascular changes is important for understanding its pathophysiology. We aimed to investigate retinal and choroidal microvascular changes according to the RP stages. The stages of RP were classified into three stages according to the integrity and width of the inner segment ellipsoid zone: early, ≥ 2500 μm; moderate, < 2500 μm; advanced, absence. Using optical coherence tomography angiography, quantitative microvascular parameters were analyzed. In total, 91 eyes from 49 patients were included. For the superficial capillary plexus (SCP) and deep capillary plexus (DCP), perfusion densities (PDs) in the early stage (SCP: 37.32 ± 8.11%; DCP: 21.19 ± 9.15%) were greater than those in moderate (SCP: 34.16 ± 6.65%, P = 0.011; DCP: 15.67 ± 8.85%, P = 0.031) and advanced stages (SCP: 33.71 ± 9.02%, P = 0.030; DCP: 12.83 ± 6.29%, P < 0.001). The choroidal vascularity index in the early stage (0.58 ± 0.03) was greater than those in the moderate (0.57 ± 0.02, P = 0.017) and advanced stage (0.56 ± 0.02, P = 0.033). The area and perimeter of foveal avascular zone (FAZ) in advanced stage (0.44 ± 0.26 mm2, 2.96 ± 0.86 mm, respectively) were larger than those in early (0.26 ± 0.11 mm2, P = 0.020; 2.19 ± 0.53 mm, P = 0.006, respectively) and moderate stage (0.28 ± 0.13 mm2, P = 0.043; 2.24 ± 0.67 mm, P = 0.013, respectively). During RP disease progression, retinal and choroidal microvascular vessel density decreases in the early stage, followed by FAZ enlargement in the advanced stage.

Macula vs periphery in diabetic retinopathy: OCT-angiography and ultrawide field fluorescein angiography imaging of retinal non perfusion.

To investigate the association between peripheral non-perfusion index (NPI) on ultrawide-field fluorescein angiography (UWF-FA) and quantitative OCT-Angiography (OCT-A) metrics in the macula. In total, 48 eyes with UWF-colour fundus photos (CFP), UWF-FA (California, Optos) and OCT-A (Spectralis, Heidelberg) were included. OCT-A (3 × 3 mm) was used to determine foveal avascular zone (FAZ) parameters and vessel density (VD), perfusion density (PD), fractal dimension (FD) on superficial capillary plexus (SCP). NPI's extent and distribution was determined on UWF-FA within fovea centred concentric rings corresponding to posterior pole (<10 mm), mid-periphery (10-15 mm), and far-periphery (>15 mm) and within the total retinal area, the central macular field (6×6 mm), ETDRS fields and within each extended ETDRS field (P3-P7). Macular PD was correlated to NPI in total area of retina (Spearman ρ = 0.69, p < 0.05), posterior pole (ρ = 0.48, p < 0.05), mid-periphery (ρ = 0.65, p < 0.05), far-periphery (ρ = 0.59, p < 0.05), P3-P7 (ρ = 0,55 at least, p < 0.05 for each), central macula (ρ = 0.47, p < 0.05), total area in ETDRS (ρ = 0.55, p < 0.05). Macular VD and FD were correlated to NPI of total area of the retina (ρ = 0.60 and 0.61, p < 0.05), the mid-periphery (ρ = 0.56, p < 0.05) and far-periphery (ρ = 0.60 and ρ = 0.61, p < 0.05), and in P3-P7 (p < 0.05). FAZ perimeter was significantly corelated to NPI at posterior pole and central macular area (ρ = 0.37 and 0.36, p < 0.05), and FAZ area to NPI in central macular area (ρ = 0.36, p < 0.05). Perfusion macular metrics on OCT-A correlated with UWF-FA's non-perfusion (NP), particularly in the retina's mid and far periphery, suggesting that OCT-A might be a useful non-invasive method to estimate peripheral retinal NP.

Morphological characteristics of the foveal avascular zone in pathological myopia and its relationship with macular structure and microcirculation.

To explore the characteristics of macular structure, microcirculation, and foveal avascular zone (FAZ) morphology in pathological myopia and to research the associations between these factors and pathological myopia. This is a cross-sectional study. The study included 103 eyes with non-high myopia and 206 eyes with high myopia (139 with simple high myopia and 67 with pathological myopia). Macular structural and microcirculation parameters were determined using optical coherence tomography angiography (OCTA). The FAZ morphological parameters were measured manually using Image J software. Correlations between pathological myopia and various factors were analyzed. Patients with pathological myopia had a thinner retinal thickness (RT) and choroidal thickness (CT) and a lower retinal superficial vascular density (SVD), retinal deep vascular complex density (DVD), choriocapillaris perfusion area (CCPA), and choroidal vascularity index (CVI) (all P < 0.05). Patients with pathological myopia had a larger FAZ area, perimeter, major axis, minor axis, acircularity index (AI), and lower circularity index (CI) (all P < 0.01). The axial length (AL), the major axis of the superficial FAZ, CI, and AI were significantly correlated with myopia severity (all P < 0.05). Patients with pathological myopia exhibited worse macular microcirculation and thinner macular retina and choroid. The FAZ in pathological myopia was larger and more irregular. The AL, CI, and AI were significantly associated with myopia severity. Thus, CI and AI might serve as new indicators for monitoring the progression of myopia. Further investigations should be performed. Clinical Trials.gov Identifier: ChiCTR2100046590.

Correlations between Retinal Microvascular Parameters and Clinical Parameters in Young Patients with Type 1 Diabetes Mellitus: An Optical Coherence Tomography Angiography Study

Objectives: In the current study, we investigated the correlations between retinal microvascular parameters using optical coherence tomography angiography (OCTA) and clinical parameters for a group of 69 young patients with type 1 diabetes mellitus (T1DM). Materials and Methods: This retrospective, exploratory study enrolled 69 patients between 5 years old and 30 years old who met the inclusion criteria. All the study participants underwent a comprehensive ophthalmic examination and OCTA scans for the evaluation of the retinal microcirculation. The retinal OCTA parameters were correlated with the following clinical parameters: the patient’s age at the onset of the disease, the duration of T1DM, the BMI at the time of enrollment in the study, the HbA1C values at onset, the mean values of HbA1C over the period of monitoring the disease and the degree of DKA at onset. Results: For the study group, the foveal avascular zone (FAZ) area and perimeter correlated positively with the mean value of HbA1C (Pearson correlation, Sig.2-Tailed Area: 0.044; perimeter: 0.049). The total vessel density in the superficial capillary plexus (SCP) correlated negatively with the duration of T1DM, based on the superior and inferior analyzed areas (Spearman correlation, Sig.2-Tailed SCP in total region: 0.002; SCP in the superior region: 0.024; SCP in the inferior region: 0.050). The foveal thickness also correlated negatively with the levels of diabetic ketoacidosis (DKA) at onset (Spearman correlation, Sig.2-Tailed: 0.034) and the levels of HbA1C at onset (Spearman correlation, Sig.2-Tailed: 0.047). Further on, the study patients were distributed into two groups according to the duration of the disease: group 1 included 32 patients with a duration of T1DM of less than 5 years, and group 2 included 37 patients with a duration of T1DM of more than 5 years. Independent t-tests were used to compare the OCTA retinal parameters for the two subgroups. While the FAZ-related parameters did not show significant statistical differences between the two groups, the vessel densities in both the SCP and DCP were significantly lower in group 2. Conclusions: Our data suggest that specific alterations in OCTA imaging biomarkers correlate with various clinical parameters: the FAZ area and perimeter increase with higher mean values of HbA1C, leading to poor metabolic control. Moreover, the SCP total vessel density decreases as the duration of T1DM increases. Regarding the vessel densities in the SCP and the DCP, they decrease with a duration of the disease of more than 5 years.

Comparative analysis of optical coherence tomography angiography (OCTA) results between Behçet's disease patients and a healthy control group.

This study aimed to compare optical coherence tomography angiography (OCTA) findings between patients with Behçet's disease (BD) and individuals with healthy eyes. A cross-sectional study. This cross-sectional study was conducted on patients (67 eyes) with BD who were referred to Feiz Hospital and healthy eyes (43 eyes). All subjects underwent Snellenvisualacuity, a slit-lamp examination, measuring intraocular pressure, conducting a dilated fundus examination, OCTA imaging, and spectral-domain (SD)-OCT imaging. OCTA retinal vascular measurements including optic nerve VD, macular-associated VD( superficial and deep), foveal avascular zone (FAZ) area, FAZ perimeter (PERIM), and vessel density within a 300-μm-wide region of the FAZ (FD) were compared between the groups. A significant difference was evident between the two groups (healthy one group and BD group) in terms of parafoveal and perifoveal total retinal thickness, total pRNFL VD in all quadrants except the inferior sector (P < 0.05), and macular superficial, and deep VD in all regions except temporal and superior perifoveal VD (P < 0.05) following adjustments for age, gender, and signal strength index. When comparing the two groups, ocular Behçet's disease (BD) and non-ocular BD, it was evident that peripapillary vessel density (VD) exhibited a significant decrease in ocular BD eyes in all sectors except for the superior and inferior ones, as compared to non-ocular BD eyes. In addition, the comparison of ocular BD and non-ocular BD showed superficial and deep VDs were lower in ocular BD than non-ocular BD in all regions. According to these findings, peripapillary and macular vessel density is affected in BD. Key Points • The study utilized OCTA to compare retinal features in Behçet's disease (BD) patients and healthy individuals, revealing significant differences in retinal thickness and vessel density. • Ocular BD demonstrated reduced peripapillary vessel density compared to non-ocular BD. • The demonstrated association between ADMA and cIMT in patients with early SSc may suggest a role of NO/ADMA pathway in the initiation of macrovascular injury in SSc.

Retinal capillary plexus in Parkinson's disease using optical coherence tomography angiography.

To evaluate the alterations of the retinal microvasculature and foveal avascular zone in patients with Parkinson's disease (PD) using optical coherence tomography angiography (OCT-A). A retrospective study of PD patients examined in the Ophthalmology Department of the General Hospital of Athens, "Georgios Gennimatas" from March 2021 to March 2022 was conducted. Totally 44 patients with PD were included and 18 healthy controls were examined, hence a total of 124 eyes were enrolled in the study. The foveal and parafoveal superficial and deep capillary plexus vascular density (fSCP-VD, fDCP-VD, pSCP-VD, pDCP-CD) and foveal avascular zone (FAZ) were quantified with OCTA. Optical coherence tomography (OCT) was used to measure macular thickness. Our statistical analysis was conducted by using a mixed effect linear regression model. After adjustment for age and gender, the mean parafoveal superficial capillary plexus vascular density (pSCP-VD) and mean parafoveal deep capillary plexus vascular density (pDCP-VD) were significantly decreased in individuals with PD (P<0.001 in both) by -2.35 (95%CI -3.3, -1.45) and -7.5 (95%CI -10.4, -4.6) respectively. fSCP-VD and fDCP-VD didn't approach statistical significance. The FAZ area and perimeter were significantly decreased (P<0.001 in both) by -0.1 mm2 (95%CI -0.13, -0.07) and -0.49 mm2 (95%CI -0.66, -0.32) respectively. Circularity didn't approach statistical significance. Central retinal thickness (CRT) was significantly decreased in individuals with PD (P<0.001) by -23.1 µm (95%CI -30.2, -16) and temporal retinal thickness (TRT) was decreased (P=0.025) by -11 µm (95%CI -22, -1.5) while nasal retinal thickness (NRT) only approached statistical significance (P=0.066). The mean pSCP-VD, pDCP-VD, CRT and TRT are significantly decreased and FAZ is altered in individuals with PD. These findings can be potentially used as biomarkers for the diagnosis and evaluation of early PD.

Evaluation of early retinal changes in patients on long-term hydroxychloroquine using optical coherence tomography angiography.

Connective tissue diseases (CTD), including systemic lupus erythematosus and rheumatoid arthritis (RA), have long been treated with hydroxychloroquine (HCQ). However, prolonged HCQ use poses a risk of adverse effects, particularly retinopathy. To detect early retinal changes assessed by optical coherence tomography angiography (OCTA) in CTD patients with long-term HCQ treatment and to explore the relationship between OCTA parameters and the concentrations of HCQ and its metabolites. A cross-sectional study conducted from March 2020 to October 2021 at the First Affiliated Hospital of Anhui Medical University. The area and perimeter of the foveal avascular zone (FAZ), the thickness of the fovea and parafovea, and the vascular density of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in each area of the macula were measured by OCTA in 43 CTD patients treated with HCQ for over 6 months. Meantime, blood concentrations of HCQ and its metabolites were determined by high-performance liquid chromatography-tandem mass spectrometry, and the clinical documents of all 43 involved patients were collected. There is no significant correlation between OCTA outcomes and the patient's age, disease duration, and weight-dependent dose. HCQ cumulative duration positively correlated with FAZ area and perimeter (r = 0.419, p = 0.005 and r = 0.407, p = 0.007, respectively) and negatively correlated with the foveal vessel density in DCP (r = -0.378, p = 0.012). HCQ cumulative dose had a positive correlation with FAZ area and perimeter (r = 0.445, p = 0.003 and r = 0.434, p = 0.004, respectively) and had a negative correlation with foveal vessel density in SCP and DCP (r = -0.383, p = 0.011 and r = -0.424, p = 0.005, respectively). OCTA outcomes did not correlate with HCQ and its metabolite concentrations. OCTA could be used to detect microvascular changes in the macula of CTD patients with long-term HCQ therapy. It was not found the concentrations of HCQ and its metabolites were associated with retinal vascular changes.

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.

Microvascular changes after pars plana vitrectomy for rhegmatogenous retinal detachment repair: A comparative study based on gas tamponade agent.

The purpose of this study was to investigate the effect of gas tamponade on microvascular changes in patients with rhegmatogenous retinal detachment (RRD), who underwent pars plana vitrectomy (PPV), using optical coherence tomography angiography (OCTA). Participants in this study were 48 patients with RRD, who were treated with PPV and gas tamponade without internal limiting membrane peeling. All participants underwent slit-lamp examination, fundoscopy, spectral domain-optical coherence tomography and optical coherence tomography angiography at month 6 postoperatively. The fellow untreated eyes were also examined and served as the control data. A statistically significant enlargement in the foveal avascular zone (FAZ) in both the superficial (p = 0.002) and the deep capillary plexus (p = 0.01) was noticed 6 months postoperatively in patients with RRD treated with PPV compared to the fellow eyes. The foveal avascular zone perimeter was increased in the operated eyes in the deep capillary plexus (p = 0.0003) and the foveal avascular zone circularity was decreased in both the superficial (p = 0.045) and the deep capillary plexus (p < 0.001) compared to the fellow eyes. The vessel density was not significantly different between the operated and the fellow eyes in the superficial and the deep capillary plexus. The vessel density and the foveal avascular zone parameters were comparable between the C3F8 and SF6 groups. Specific microvascular indices as measured by OCTA were statistically different between the operated and the fellow eyes in the superficial and deep capillary plexus. C3F8 and SF6 as gas tamponades did not seem to differ in their impact on the microvascular parameters.

Association of Male Sex and Microvascular Alterations on Optical Coherence Tomography Angiography in Diabetes.

Epidemiologically, men have a higher incidence, severity, and progression of diabetic retinopathy (DR) than women. We investigated microvascular differences between men and women with diabetes on optical coherence tomography angiography (OCTA). Three × 3 mm OCTA macula scans of non-diabetic and patients with diabetes were obtained. Vascular parameters included parafoveal vessel density (VD), vessel length density (VLD), and flow index (FI) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) as well as foveal avascular zone (FAZ) area and perimeter. Multivariable linear regression was used for statistical analysis. There were 1809 patients with diabetes and 217 non-diabetic participants that were included in this study. Diabetic individuals included those with no DR (n = 1356), mild non-proliferative DR (NPDR; n = 286), moderate NPDR (n = 126), and severe NPDR/proliferative DR (PDR; n = 41). Male sex was significantly associated with smaller FAZ area/perimeter and lower DCP VLD in both non-diabetic subjects and patients with diabetes. Male sex in the diabetic group was additionally associated with lower SCP VD/VLD and DCP VD. Addition of an interaction between male sex and diabetes status in the interaction analysis showed that being male and diabetic conferred increased reduction in DCP VD and VLD compared to sex-based changes in non-diabetics. Larger FAZ perimeter, lower SCP VD/VLD, and lower DCP VLD were associated with poorer visual acuity in diabetics. On OCTA, male patients with diabetes may have more severe microvascular disease especially in the DCP compared to women. Sex-based alterations in diabetic microvascular disease has the potential to influence future basic and clinical studies as well as the implementation of OCTA disease markers.

Evaluation of Choroidal and Retinal Features in Patients with Primary Vasculitis-An Original Optical Coherence Tomography and Optical Coherence Tomography Angiography Study.

Ocular manifestations have been described in the course of various types of vasculitis. However, there seems to be no routine ophthalmological examinations for patients suffering from those diseases. To ensure holistic care we aimed to investigate any retinal and choroidal abnormalities in patients suffering from primary vasculitis. The objective was to use non-invasive methods, which would not be time- and cost-consuming, yet would be helpful in routine tests. We conducted a prospective and observational study in 41 patients (78 eyes) with 5 types of primary vasculitis, including: Takayasu's arteritis; giant cell arteritis; Buerger's disease; granulomatosis with polyangiitis; and polyarteritis nodosa. A total of 44 healthy individuals were enrolled in the control group for comparison (88 eyes). With the use of optical coherence tomography, optical coherence tomography angiography, and MATLAB, the following parameters were assessed: choroidal thickness; vascularity index; area and perimeter of foveal avascular zone; and circularity index. The following parameters were lower in the study group compared to the control group: mean nasal and temporal CTs; mean central, temporal, and nasal CVI; and mean CI. In contrast, the results of mean central CT as well as the area and perimeter of FAZ were higher in the study group. The differences were statistically significant in the case of all parameters except for CI. Conducting routine ophthalmological examinations in patients diagnosed with vasculitis by assessment of the retina and choroid by measuring parameters like CT, CVI, area and perimeter of FAZ, and CI could be beneficial, as it may detect pathological changes before any ocular symptoms alarm the patients. CVI seems to be especially promising for choroidal evaluation, as it appears to be less influenced by various factors compared to CT.

Comparative study of widefield swept-source optical coherence tomography angiography in eyes with concomitant age-related macular degeneration and diabetic retinopathy

Background/aimsWe sought to evaluate widefield swept-source optical coherence tomography angiography (WF SS-OCTA) among eyes with concomitant age-related macular degeneration (AMD) and diabetes mellitus or diabetic retinopathy (DM/DR).MethodsThis cross-sectional, comparative study...

LONGITUDINAL MICROVASCULAR AND NEURONAL RETINAL EVALUATION IN PATIENTS WITH DIABETES MELLITUS TYPES 1 AND 2 AND GOOD GLYCEMIC CONTROL.

To evaluate microvascular and neuronal changes over 3 years in patients with Type 1/2 diabetes mellitus (DM1/DM2), good metabolic control, and no signs of diabetic retinopathy. In this prospective, longitudinal study, 20 DM1, 48 DM2, and 24 controls underwent macular optical coherence tomography and optical coherence tomography angiography at baseline and after 3 years. Following parameters were considered: thickness of the central macula, retinal nerve fiber layer, ganglion cell (GCL+/GCL++) complex; perfusion and vessel density and fractal dimension at the superficial and deep capillary plexuses; choriocapillaris flow deficits; and foveal avascular zone metrics. MATLAB and ImageJ were used for optical coherence tomography angiography scans analyses. The mean HbA1c was 7.4 ± 0.8% in DM1 and 7.2 ± 0.8% in DM2 at baseline, with no change at 3 years. No eye developed diabetic retinopathy. In longitudinal analyses, perfusion density at superficial capillary plexuses ( P = 0.03) and foveal avascular zone area and perimeter ( P < 0.0001) significantly increased in DM2 compared with other groups. No longitudinal changes occurred in optical coherence tomography parameters. In comparisons within groups, DM2 had a significant thinning of GCL++ in the outer ring, decreased perfusion density at deep capillary plexuses and choriocapillaris flow deficits, and increase in foveal avascular zone perimeter and area in deep capillary plexuses; DM1 had an increase in foveal avascular zone perimeter in deep capillary plexuses ( P < 0.001 for all comparisons). Longitudinal data showed significant microvascular retinal changes in DM2. No changes were detected in neuronal parameters and in DM1. Longer and larger studies are needed to confirm these preliminary data.

Changes of retinal vessel density in low to moderate myopic eyes with orthokeratology evaluated by optical coherence tomography angiography.

To explore the effect of orthokeratology (OK) fitting on retinal vessel density in low to moderate myopia adolescents by using optical coherence tomography angiography. Children aged 10 to 14y with a cycloplegic spherical equivalent refraction of -0.50 diopter (D) to -5.00 D and astigmatism with more than -1.50 D were recruited. The enrolled adolescents were divided into OK group and spectacle group. During regular follow-up, adolescents were measured respectively at pre-wear, 1, 3, and 6mo after treatment. The follow-up included uncorrected distance visual acuity (UDVA), axial length (AL), superficial capillary plexus density (SCPD), deep capillary plexus density (DCPD), central retinal thickness (CRT), foveal avascular zone area (FAZ-A), foveal avascular zone perimeter (FAZ-P) and foveal vessel density in a 300-µm-wide region around foveal avascular zone (FD-300). The collected data were analyzed using statistical methods. By one month, SCPD significantly increased in the fovea and superior retina, and DCPD significantly increased inferiorly in OK group compared to spectacle group (P<0.05). By three months, there were significant increases in SCPD in the fovea and inferior retina, and DCPD in the parafovea, superior, and inferior retina in OK group (P<0.05), while the increase in SCPD and DCPD in the fovea were observed by six months (P<0.05). The FD-300 significantly increased at every follow-up in OK group compared to spectacle group (P<0.05). No significant differences in the CRT, FAZ-A and FAZ-P and FD-300 were observed between two groups (P>0.05). OK group showed a significant improvement in UDVA after wearing OK, compared to spectacle group (P<0.01), while the AL did not show a significant difference between two groups (P>0.05). Short-term OK worn can increase local retinal vessel density in adolescents with low-to-moderate myopia.

The Relationship Between Artificial Intelligence–Assisted OCT Angiography–Derived Foveal Avascular Zone Parameters and Visual-Field Defect Progression in Eyes with Open-Angle Glaucoma

To investigate clinical factors associated with foveal avascular zone (FAZ) parameters obtained using OCT angiography (OCTA) with assistance from a previously developed artificial intelligence (AI) platform in eyes with open-angle glaucoma (OAG). Retrospective longitudinal. This study followed up 885 eyes of 558 patients with OAG for ≥ 2 years; all eyes underwent≥ 5 Humphrey visual-field (VF) tests and had 3.0×3.0 mm macular OCTA scans available. Average total deviation (TD) in the superior, superocentral, inferocentral, and inferior sectors of the Humphrey 24-2 program was calculated. We collected 3.0×3.0 mm macular OCTA images from each patient and used a previously developed AI platform with these images to obtain FAZ parameters, including FAZ area, FAZ circularity index (CI), and FAZ perimeter. Multivariable linear mixed-effects models were used to analyze the relationship between FAZ parameters, TD or TD slope in each quadrant, and systemic factors, adjusting for potential confounding factors, including axial length. Ophthalmic and systemic variables, FAZ parameters, and TD or TD slope in each quadrant. The multivariable model showed that FAZ parameters were correlated with both TD and TD slope in the inferocentral quadrant (β=-0.244 - 0.168, P < 0.001). Both upper-half and lower-half FAZ parameters were better associated with TD-inferocentral and TD-inferocentral slope than TD-superocentral or TD-superocentral slope in terms of β size and statistical significance, indicating that there was no evident vertical anatomical correspondence between TD in the central quadrant and FAZ parameters. Foveal avascular zone area enlargement was associated with female gender (β=0.242, P= 0.003). Loss of FAZ circularity was associated with both aging and comorbid sleep apnea syndrome (SAS) (yes: 1, no: 0) (β=-0.188, P < 0.001; β=-0.261, P= 0.031, respectively). Foveal avascular zone perimeter elongation was associated with aging and female gender (β=0.084, P= 0.040; β=0.168, P= 0.042, respectively). Artificial intelligence-assisted OCTA-measured FAZ enlargement and irregular shape might be good markers ofocular hypoperfusion and associated inferocentral VF defect progression in eyes with OAG. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.