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

Purpose: To evaluate the effects of low blood magnesium levels on the optic nerve, retina, and retinal vascular structure. Methods: This observational and cross-sectional study was conducted between June 2019 and May 2020 with participants aged 20–39 years, who had a visual acuity of ≥20/20, the axial length of 22–24.5 mm, refractive defect spherical equivalent of ≤±3D, and intraocular pressure of ≤21 mm Hg. All participants had a complaint of twitching in their eyes. The participants with normal serum magnesium levels constituted the control group, and patients with hypomagnesemia constituted the patient group. Updated AngioScan software (Navis ver. 1.8.0.) of Nidek’s RS-3000 Advance system was used to analyze the spectral domain-optical coherence tomography (SD-OCT) and optical coherence tomography-angiography (OCT-A) images. Results: A total of 100 right eyes of 100 individuals was included in the study. The mean retinal nerve fiber layer (RNFL) thickness was 108.52 ± 12.46 μm in the control group, and 97.3 ± 9.7 μm in the hypomagnesemia group (P < .001). In the control group, the global superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel densities (VDs) were 41.92 ± 2.29, and 37.54 ± 3.83, respectively. In the patient group, the global SCP and DCP VDs were 37.66 ± 3.14, and 32.95 ± 5.57, respectively. The SCP and DCP VD percentages were significantly lower in the patient group. The mean foveal avascular zone (FAZ) area, perimeter and circularity index (CI) were 0.32 ± 0.13 mm2, 2.89 ± 0.59 mm, and 0.52 ± 0.09, respectively, for the control group and 0.38 ± 0.11 mm2, 2.99 ± 0.64 mm, and 0.38 ± 0.1, respectively, for the patient group. The FAZ area and perimeter were significantly higher (P = .013 and P = .001) and FAZ CI was significantly lower (P < .001) in the patients with hypomagnesemia. Conclusion: Our study revealed that OCT and OCT-A measurements may be used in the determination of the optic nerve and retinal vascular structure changes in hypomagnesemia.

Background and objective Vascular endothelial growth factor-A (VEGF-A) plays an important role in the development of diabetic macular edema (DME). In this study, we aimed to correlate optical coherence tomography angiography (OCTA) parameters with serum VEGF-A levels in DME. Methodology We conducted a prospective study, which examined 44 eyes of 32 DME patients (mean age: 56.0 ±9.1 years) for visual acuity (VA), defective colour vision (CV), and contrast sensitivity (CS). The OCT was done for central foveal thickness (CFT), sub-foveal choroidal thickness (SFCT), neurosensory detachment (NSD), epiretinal membrane (ERM), and disorganized retinal inner layers (DRIL). The OCTA was used to study the foveal avascular zone (FAZ) in superficial capillary plexus (SCP) and vessel density (VD) in six retino-choroidal layers, including SCP, deep capillary plexus (DCP), outer retina (OR), outer retinal chorio-capillaries (ORCC), chorio-capillaries (CC), and choroid. The serum VEGF-A levels were measured using an enzyme-linked immunosorbent assay (ELISA) kit. The eyes were treated with a single intravitreal injection of 0.3 mg/0.05 ml ranibizumab biosimilar (RbB). The subjects were re-examined after a short period of one month for visual, OCT, and OCTA parameters and serum VEGF-A levels. A correlation between OCTA parameters and serum VEGF-A was done on both occasions. Results At baseline, the logarithm of the minimum angle of resolution(logMAR) best-corrected visual acuity (BCVA) was 0.82 ±0.13, CFT 464.60 ±173.06 microns, SFCT 238.02 ±42.88 microns, and the serum VEGF-A level was 487.94 [interquartile range (IQR): 305 to 775.52] pg/ml. There was a positive correlation of serum VEGF-A level with LogMAR BCVA (r=0.15), CFT (Rho=0.02) and SFCT (Rho=0.14), while there was a negative correlation with FAZ area (Rho=-0.20), perimeter (Rho=-0.19) and VD of SCP (Rho=-0.22), DCP (Rho=-0.02), OR (Rho=-0.10), ORCC (Rho=-0.12), CC (Rho=-0.10) and choroid (Rho=-0.17). After a short follow-up of one month following intravitreal injection, LogMAR BCVA was 0.53 ±0.22, CFT 350.07 ±153.02 microns, SFCT 232.40 ±44.30 microns, and the serum VEGF-A level measured 404.02 (IQR 204.61 to 750.87) pg/ml. There was a positive correlation of serum VEGF-A level with LogMAR BCVA (r=0.48), CFT (Rho=0.19), and SFCT (Rho=0.11), while there was a negative correlation of serum VEGF-A levels with FAZ area (Rho=-0.01), perimeter (Rho=-0.06), and VD of SCP (Rho=-0.22), DCP (Rho=-0.13), OR (Rho=-0.10), ORCC (Rho=-0.25), CC (Rho=-0.18), and choroid (Rho=-0.29). The correlation coefficient values indicated that all observed correlations were weak. Conclusion In our study, the BCVA decreased while CFT and SFCT increased, along with an increase in serum VEGF-A levels. The higher serum VEGF-A was related to smaller FAZ and lower retino-choroidal VD. The observed weak correlation of ocular, OCT, and OCTA features with serum VEGF-A levels may limit the predictive value and clinical utility of these biomarkers in the management of DME.

We aim to find an association between neovascularization (NVn) and optical coherence tomography angiography (OCTA) parameters in proliferative diabetic retinopathy (PDR). In a prospective study, 41 subjects including 28 (68%) males and 13 (32%) femaleshaving PDR were examined for neovascularization disc (NVD) and neovascularization elsewhere (NVE) clinically and with fundus fluorescein angiography (FFA). A total of 79 eyes were found to be involved. We examined OCTA parameters including foveal avascular zone (FAZ) size, perimeter and circularity, and vessel density (VD) in the superficial capillary plexus (SCP), deep capillary plexus (DCP), outer retina (OR), outer retinal chorio-capillaries (ORCC), chorio-capillaries (CC), and choroid (C) in these subjects. In eyes with NVD, the central foveal thickness (CFT) (p=0.83) and sub-foveal choroidal thickness (SFCT) (p=0.08) were higher, the FAZ area was significantly larger (p=0.005), and the VD was lower in all retino-choroidal layers. However, it was significantly lower in SCP foveal (p=0.005) and ORCC foveal (p=0.05) than in eyes not having NVD. For NVE, the CFT (p=0.03) and SFCT (p=0.01) were more in affected eyes. The eyes without NVE had a better circularity index (p=0.07) and the highest VD in OR slab (p=0.02) than those eyes that had NVE < ½ disc area (DA) and NVE > ½ DA. On comparing eyes without NVE, NVE < ½ DA, and NVE > ½ DA, the latest had the highest VD in SCP (p=0.59) and lowest VD in DCP (p=0.43) and OR (p=0.02). The VD in ORCC, CC, and choroid was highest in the no NVE group, followed by the NVE > ½ DA and NVE < ½ DA groups in that order. The subjects having vitreous hemorrhage (VH) and intra-retinal microvascular abnormalities (IRMA) had higher values for CFT and SFCT than eyes without these. An increased CFT and SFCT are associated with the appearance of NVD, NVE, VH, and IRMA. The presence of NVD, VH, and IRMA is associated with a larger FAZ area, while that of IRMA and NVE is associated with reduced FAZ circularity. Eyes with NVD, VH, and IRMA had lesser VD in all the retino-choroidal layers. Eyes with NVE > ½ DA had the highest VD in SCP and lowest in DCP and OR; this pattern of VD foretells severer affection in NVE. IRMA was associated with a larger FAZ area, larger FAZ perimeter, and lesser circularity, indicating the presence of central ischemia.

OCT Angiography Metrics Predict Progression of Diabetic Retinopathy and Development of Diabetic Macular Edema: A Prospective Study

To investigate optical coherence tomography angiography (OCT-A) findings of foveal avascular zone (FAZ) metrics and macular & peripapillary vessel densities (VD) in subjects with multiple sclerosis (MS). The study design was prospective and cross-sectional. FAZ metrics and VDs of the superficial capillary plexus (SCP), deep capillary plexus (DCP), retinal peripapillary capillary plexus (RPCP) along with the structural OCT measurements were scanned by using the Nidek's RS-3000 Advance in MS patients and healthy controls. All subject also underwent an assessment of visual evoked potentials (VEPs). The relationships between the OCT-A parameters with other clinical findings were analysed. Forty-seven MS patients (94 eyes) and 61 healthy volunteers (122 eyes) were included in this study. Thirty-five eyes of the MS patients had an ON history. The structural OCT measurements were significantly differed between the groups (P < 0.001). All FAZ metrics were inversely correlated with central foveal thickness (CFT) (P < 0.001). The FAZ area and perimeter were inversely correlated with the VD of both SCP and DCP (P < 0.05). The VDs of SCP and DCP were significantly differed between the study groups (P < 0.001). The VEP latency was inversely correlated with the retinal nerve fibre layer, macular and ganglion cell layer thicknesses, the VD of SCP, and the VD of the DCP (P < 0.001). Based on OCT angiography, VDs of macular and peripapillary area may be useful in detecting damage from ON in patients with MS.

To determine normal macular vessel density (VD) and foveal avascular zone (FAZ) values using optical coherence tomography angiography (OCTA) analysis in healthy adults. As part of the Prospective Epidemiological Research Studies in Iran (PERSIAN) Organizational Cohort study at Mashhad University of Medical Sciences (POCM), we conducted a cross-sectional study using 3 × 3 and 6 × 6 mm OCTA scans to evaluate the VD of the macular superficial capillary plexus (SCP), deep capillary plexus (DCP), and the FAZ area in healthy adults. The study included 792 participants, with a mean age of 39.8 ± 6.8 years. There were 359 males with a mean age of 39.9 ± 7.8 years and 440 females with a mean age of 39.4 ± 6 years. The mean values of various parameters were measured, including the right eye whole image SCP and DCP VDs, FAZ area, FAZ perimeter, and fovea VD in a 300 µm wide zone around FAZ (FD). These values were found to be 45.9 ± 2.6%, 50.2 ± 3%, 0.3 ± 0.1mm2, 2.1 ± 0.4 mm, and 50.4 ± 3.3%, respectively. Females and younger participants had significantly higher mean values of whole image SCP and DCP VDs. Additionally, all FAZ parameters had significantly higher values in females, while younger participants had significantly higher mean FD values. Simple linear regression analyses showed that age was negatively correlated with right eye SCP and DCP VDs. Our study established standard SCP and DCP VD values influenced by age and gender. Age correlates negatively with both, DCP VDs correlate negatively with height and weight, and SCP VDs correlate positively with diastolic blood pressure.

Purpose: To provide clinical evidence of the associations between retinal neuronal degeneration and microvasculopathy in diabetic retinopathy (DR).Methods: This case-control study included 76 patients (76 eyes) with type 2 diabetes mellitus (DM), and refraction error between −3.0 and +3.0 D. The eyes were assigned into DM (without DR), non-proliferative DR (NPDR), and proliferative DR (PDR) groups. Age-, sex-, and refractive error-matched normal subjects were enrolled as controls. The mean retinal thickness (mRT), the relative mean thickness of the retinal nerve fiber layer (rmtRNFL, mtRNFL/mRT), ganglion cell layer (rmtGCL), ganglion cell complex (rmtGCC) layer, foveal avascular zone area (FAZa), FAZ perimeter (FAZp), FAZ circularity index (FAZ-CI), and vessel density (VD) in superficial capillary plexus (SCP) and deep capillary plexus (DCP) were assessed by swept-source optical coherence tomography (OCT) and OCT angiography (OCTA). Group comparison and Spearman's partial correlation coefficient analysis were applied to evaluate the correlation between these morphological parameters.Results: rmtRNFL, FAZa, and FAZp in SCP and DCP increased with the DR severity (prmtRNFL < 0.001; pFAZa, SCP = 0.001; pFAZa, DCP = 0.005; pFAZp, SCP < 0.001; pFAZp, DCP < 0.001). The rmtGCL, FAZ-CI in SCP and DCP, and VD in DCP decreased with the DR severity (prmtGCL = 0.002, pFAZ−CI, SCP = 0.002; pFAZ−CI, DCP < 0.001, pVD, DCP < 0.001). After controlling age, sex, duration of diabetes, and hypertension, the rmtRNFL, FAZa in SCP and DCP, and FAZp in SCP and DCP were correlated with the severity of DR (p < 0.05), while VD in SCP and DCP, FAZ-CI, and rmtGCL were negatively correlated with the severity of DR (p < 0.05). The rmtGCL was negatively correlated with the FAZa in SCP (r = −0.34, p = 0.002) and DCP (r = −0.23, p = 0.033), and FAZp in SCP (r = −0.37, p = 0.001) and DCP (r = −0.32, p = 0.003), but positively correlated with VD in SCP (r = 0.26, p = 0.016), VD in DCP (r = 0.28, p = 0.012), and FAZ-CI in DCP (r = 0.31, p = 0.006).Conclusions: rmtRNFL, FAZ-CI in SCP and DCP, and FAZp in SCP are strong predictors of the severity of DR. The ganglion cell body loss is highly correlated with increased FAZp and FAZa, decreased FAZ-CI, and reduced VD with the severity of DR.

This study aimed to investigate subclinical retinal microvascular changes with optical coherence tomography angiography (OCTA) in patients with systemic lupus erythematosus (SLE) and healthy controls (HCs), and to evaluate the relationship between OCTA findings and Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K). In this study, 47 eyes of SLE and 41 eyes of healthy control (HC) were evaluated. The SLE patients were divided into two subgroups: low disease activity (LDA) (SLEDAI≤5) and high disease activity (HDA) (SLEDAI>6). The results of OCTA were compared between SLE patients and HCs as well as the SLE subgroups. The relationship between OCTA results and SLEDAI-2K was evaluated. There were no differences in foveal avascular zone (FAZ) areas between the SLE patients and HCs. Central foveal thickness (CFT) was lower in SLE patients (p = .046). Superficial capillary plexus (SCP) vessel density (VD) in SLE patients was significantly lower only in the foveal area compared to that in HCs (p = .006). Deep capillary plexus (DCP) VD in SLE patients was significantly lower in all areas except the temporal parafoveal area compared to that in the HCs. There was no statistically significant difference between SLE groups with LDA and HDA in FAZ or any of the other areas, including SCP and DCP. When the correlation between OCTA findings and SLEDAI-2K was examined, both SCP and DCP VD were found to be negatively correlated. It was observed that DCP VDs were affected in SLE patients with LDA, and SCP VDs were also affected in addition to DCP with HDA. This suggests that DCP may be the first capillary plexus to be comprised in SLE. VDs were negatively correlated with disease activity. It was concluded that OCTA can be a useful tool in assessing subclinical retinal microvascular pathology and disease activity in patients with SLE.

ABSTRACTPurpose: To establish a normative database for macular and peripapillary vessel densities (VD) and foveal avascular zone (FAZ) metrics in healthy subjects with the new version of AngioScan software of RS-3000 Advance (Nidek Co, Ltd) optical coherence tomography angiography (OCT-A) device.Methods: The study design was prospective and cross-sectional. VDs of the SCP, deep capillary plexus (DCP), retinal peripapillary capillary plexus (RPCP) and FAZ area, perimeter and circularity index (CI) along with the structural OCT measurements were scanned by using the Nidek’s RS-3000 Advance OCT-A device in healthy subjects. The new version of the AngioScan software was used for analytics. The relations between the OCT-A parameters with age, gender and OCT parameters were analyzed.Results: A total of 128 right eyes of 128 subjects (50% female) were included in this study. We divided subjects into 3 groups in accordance with age; 19–39 years to Group 1, 40–59 years to Group 2, >60 y. to Group 3. The mean SCP and DCP VDs were 41.25 ± 2.51% and 36.01 ± 5.07% respectively (P < .001). The DCP VD was significantly different between groups (P = .001). The mean FAZ area, perimeter and CI were 0.33 ± 0.12 mm2, 2.68 ± 0.6 mm and 0.47 ± 0.09 respectively. Only FAZ CI significantly differed between groups (P = .003). The FAZ area was significantly greater in female subjects than males (P = .025). The SCP and DCP VDs were inversely correlated with FAZ area and perimeter (P < .05).Conclusion: Our study provided for the first time the normative data of the recently updated AngioScan software of Nidek. Additional studies are needed to define pathological vascular changes in ocular and systemic diseases with this new software.

To evaluate pre- and postoperative microvasculature features in eyes with different idiopathic macular epiretinal membrane (iERM) classifications using optical coherence tomography angiography (OCTA). In this retrospective study, 100 eyes with iERM were enrolled; 62 eyes underwent pars plana vitrectomy (PPV). All iERM eyes were evaluated and graded using optical coherence tomography (OCT). According to the thickness of the fovea relative to the surrounding macula from OCT radial line scans, we classified iERM into three grades. Optical coherence tomography angiography (OCTA) was used to measure the foveal avascular zone (FAZ)-related parameters and the superficial and deep capillary plexus layers using 3×3mm scans. Measurements were taken at baseline and 3months postoperatively. Best corrected visual acuity (BCVA), vessel density (VD), FAZ area, FAZ perimeter (PERIM), acircularity index (AI), and foveal vessel density (FD) were evaluated. Idiopathic macular epiretinal membrane (iERM) eyes with a higher grade had a lower FAZ area and perimeter (p<0.0001), higher foveal vessel density (FVD) both in the superficial capillary plexus (SCP) (p<0.0001) and in the deep capillary plexus (DCP) (p<0.05), and a lower parafoveal vessel density (PRVD) in the DCP (p<0.0001). The macular vessel density ratio (MVR=FVD/PRVD) increased with an increase in grade both in the SCP and in the DCP (p<0.0001). For grade 1 iERM eyes, only PRVD in the DCP significantly changed before versus after the operation (p<0.05). For grade 2 iERM eyes, the FAZ area and perimeter became larger after the operation (p<0.05). The MVR of grade 2 iERM eyes decreased postoperatively both in the SCP (p<0.05) and in the DCP (p<0.001). For grade 1 and grade 2 iERM eyes, preoperative LogMAR BCVA was negatively correlated with the FAZ area (p<0.01) and perimeter (p<0.01), and was positively correlated with the MVR in the SCP (p<0.05). Postoperative LogMAR BCVA was positively correlated with the FVD in the DCP (p<0.05). Idiopathic macular epiretinal membrane (iERM) eyes of different grades have significant differences in microvasculature features. According to OCTA, eyes with higher grades have more serious microvascular changes. Grading plays a part in predicting postoperative microvascular characteristics, and grade 1 iERM eyes have a better visual outcome compared with grade 2 iERM eyes.

Purpose: To investigate retinal vascular changes in pregnant women using optical coherence tomography angiography (OCTA). Materials and Methods: This prospective, cross-sectional study included 97 pregnant women and age-matched 34 healthy control subjects. The OCTA parameters of one eye (left) of pregnancy group and control group were compared. Besides, the OCTA parameters of three trimesters were compared between themselves and the control group. The foveal avascular zone (FAZ) area and the vessel density percentages of the superficial capillary plexus (SCP), deep capillary plexus (DCP), and radial peripapillary capillary (RPC) of all the groups were evaluated by OCTA. Results: In the pregnancy group, the vessel density of DCP was higher in all regions than the control group except the foveal region, but this difference could not reach statistical significance. On the other hand, the vessel density of SCP in the pregnancy group did not show a manifest change in all regions except the foveal region as in DCP. Although the FAZ area was wider in pregnancy group, this difference was not statistically significant (p:0.661). There was no statistically significant difference observed in vessel density of SCP, DCP, and RPC between the different trimesters and the control group, and none of these data correlated with the gestational week. Conclusion: This study showed retinal vascular changes secondary to pregnancy, especially in the vessel density of DCP. These results can provide information that should be taken into account in the evaluation and investigation of pregnancy-specific retinal vascular pathologies.

Objective: To observe changes in foveal avascular zone(FAZ) and capillary plexus in idiopathic macular epiretinal membrane (IMEM) in optical coherence tomography angiography (OCTA) and analyze their correlation with the visual acuity. Methods: Cross-sectional study. 42 patients (15 Males and 27 females, age 64.8) from the Eye Hospital of Wenzhou Medical University were included with 51 eyes diagnosed as IMEM (IMEM group), and 23 normal eyes (9 Males and 14 females, control group). All patients received the examination of fissure lamp combined with fundus pre-set lens, best corrected visual acuity (BCVA), OCT angiography (OCTA) and fundus photo. OCTA was performed on 3 mm× 3 mm sections centred on the fovea. The software automatically measured the superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density(VD) and retinal thickness(RT) and FAZ area. The IMEM eyes were compared with the normal eyes and correlation between the parameters of OCTA and BCVA was analyzed in IMEM. Independent-sample t test and MannWhitney test were used for comparison between groups, and Spearman test was used for correlation analysis. Results: LogMAR BCVA in the IMEM group was 0.40(0.15, 0.70), in the control group was 0.10(0.05, 0.22). FAZ area of IMEM group was (0.09±0.05) mm(2), while that of control group was (0.34±0.13)mm(2).Compared with the control group, in IMEM group, the BCVA was worse (Z=-4.443, P<0.001), FAZ area was smaller (t=-9.198, P<0.001), RT was increased (P<0.001), The foveal DCP and SCP vessel density was increased (t=4.280, 9.079, P<0.01), The parafoveal DCP vessel density was decreased (P<0.05), The parafoveal SCP vessel density was decreased in superior, inferior and nasal side (t=-2.759, Z=-3.998, Z=-2.108; P<0.05). The BCVA was negatively correlated with FAZ area (r=-0.337, P=0.017), positively correlated with center macular thickness (r=0.324, P=0.020). The BCVA was no correlated with foveal VD and parafoveal DCP vessel density (P>0.05), but correlated with SCP vessel density(P<0.05). Conclusions: In the IMEM eyes the BCVA was worse, FAZ area was smaller, foveal vessel density was increased and the parafoveal vessel density was decreased compared with the normal eyes. The smaller the FAZ area, the smaller foveal SCP vessel density, the poorer BCVA. There was no correlation between BCVA and DCP vessel density. Changes in VD in IMEM eyes may lead to changes in vision. (Chin J Ophthalmol, 2019, 55:757-762).

Optical coherence tomography angiography (OCT-A) is a novel imaging modality for the diagnosis of chorioretinal diseases. A number of FDA-approved OCT-A devices are currently commercially available, each with unique algorithms and scanning protocols. Although several published studies have compared different combinations of OCT-A machines, there is a lack of agreement on the consistency of measurements across OCT-A devices. Therefore, we conducted a prospective quantitative comparison of four available OCT-A platforms. Subjects were scanned on four devices: Optovue RTVue-XR, Heidelberg Spectralis OCT2 module, Zeiss Plex Elite 9000 Swept-Source OCT, and Topcon DRI-OCT Triton Swept-Source OCT. 3 mm × 3 mm images were utilized for analysis. Foveal avascular zone (FAZ) area was separately and independently measured by two investigators. Fractal dimension (FD), superficial capillary plexus (SCP), and deep capillary plexus (DCP) vessel densities (VD) were calculated from binarized images using the Fiji image processing software. SCP and DCP VD were further calculated after images were skeletonized. Repeated measures ANOVA, post hoc tests, and interclass correlation coefficient (ICC) were performed for statistical analysis. Sixteen healthy eyes from sixteen patients were scanned on the four devices. Images of five eyes from the Triton device were excluded due to poor image quality; thus, the authors performed two sets comparisons, one with and one without the Triton machine. FAZ area showed no significant difference across devices with an ICC of > 95%. However, there were statistically significant differences for SCP and DCP VD both before and after skeletonization (p < 0.05). Fractal analysis revealed no significant difference of FD at the SCP; however, a statistically significant difference was found for FD at the DCP layer (p < 0.05). The results showed that FAZ measurements were consistent across all four devices, while significant differences in VD and FD measurements existed. Therefore, we suggest that for both clinical follow-up and research studies, FAZ area is a useful parameter for OCT-A image analysis when measurements are made on different machines, while VD and FD show significant variability when measured across devices.

PurposeTo investigate retinal thickness and vascular structure in patients with non-alcoholic fatty liver disease (NAFLD) using optical coherence tomography (OCT) and OCT angiography (OCTA) and to compare the results with healthy controls.MethodThe medical records of NAFLD patients were retrospectively reviewed. Macular thickness (MT) and peripapillary retinal nerve fibre layer (pRNFL) thickness were assessed. The vessel density (VD) of Superficial Capillary Plexus (SCP), Deep Capillary Plexus (DCP), foveal avascular zone (FAZ) area, FAZ circularity index (CI), and FAZ perimeter were also recorded.ResultsThe study included 64 patients with NAFLD and 64 healthy controls. Mean MT and pRNFLT were similar between groups. The study group showed a significant reduction in VD-DCP compared to the control group (36.0 ± 5.2 vs. 38.5 ± 4.1, p < 0.001). Total FAZ area was greater in the study group than in the control group (0.42 ± 0.10 vs. 0.33 ± 0.12mm2, p < 0.001). FAZ CI also differed between groups (0.47 ± 0.08 vs. 0.53 ± 0.08, p < 0.001). Enlarged FAZ area and decreased VD-DCP were significantly associated with NAFLD severity.ConclusionIndividuals with NAFLD have certain changes in the retinal microvasculature, including reduced VD-DCP, an increased FAZ area, and a decreased of FAZ CI. The variations in VD-DCP and FAZ area exhibit discrepancies according to the disease grade. There are some limitations, including its retrospective nature, the small number of participants, the lack of analysis of the peripapillary area, and the lack of examination of longitudinal changes.

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.