Superficial Capillary Plexus Foveal Avascular Zone Area Research Articles

The Effect of Reduced Oxygen Saturation on Retinal Microvascularization in COVID-19 Patients with Bilateral Pneumonia Based on Optical Coherence Tomography Study.

The aim of the study was to evaluate changes in the retinal thickness and microvasculature based on optical coherence tomography (OCT) depending on baseline oxygen saturation (SpO2) in patients hospitalized due to COVID-19 bilateral pneumonia. The prospective study was carried out among 62 patients with COVID-19 pneumonia who underwent ophthalmic examination after hospital discharge. They were divided into three groups depending on the oxygen saturation (SpO2) on admission: ≤90% (group 1), >90% and ≤95% (group 2), and >95% (group 3). The following parameters were assessed in the ophthalmological examination and correlated with the baseline SpO2: ganglion cell layer (GCL), the retinal nerve fiber layer (RNFL) in the macular area, RNFL in the peripapillary area, the foveal avascular zone (FAZ) in superficial capillary plexus (SCP) and deep capillary plexus (DCP), vessel density (VD) in SCP, in DCP, and in the choriocapillaris plexus (CC). Baseline saturation ≤90% in COVID-19 patients caused a decrease of VD in some areas of SCP and DCP and an increase in FAZ area in SCP and DCP. In the group of patients with SpO2 ≤ 90% statistically significant thinning of the retina in the inner superior ring (ISR) (p = 0.029), the inner temporal ring (ITR) (p = 0.34), the outer superior ring (OSR) (p = 0.012), and the outer temporal ring (OTR) (p= 0.004)] was observed. The statistically significant thickening of RNFL optic disc and thinning of RNFL retina in some macular areas in patients with SpO2 ≤ 90% were reported. The size of FAZ area in SCP and vessel density were significantly greater in some areas of SCP, DCP, and CC in patients with SpO2 ≤ 90% (p = 0.025). Baseline oxygen saturation ≤90% has been found to influence the ocular parameters of OCT in COVID-19 patients. We noticed a widened FAZ zone in SCP and increased VD in some regions of the retina and choroid as a response to systemic hypoxia.

Comparison between optical coherence tomography angiography and fundus fluorescein angiography for early detection of diabetic retinopathy

Purpose This work studied the ability of optical coherence tomography angiography (OCTA) to detect and analyze microvasculature changes in the retina in early nonproliferative diabetic retinopathy (NPDR) compared with fluorescein angiography (FA) regarding the posterior pole. The study compared two groups of patients with NPDR, a group with diabetic macular edema (DME) and another group without DME, with a group of health individuals as the control. The study compared foveal avascular zone (FAZ) size, capillary perfusion (CP), and vessel density in the superficial capillary plexus (SCP) in both the control and the two groups of patients with NPDR with and without DME. The number of microaneurysms (MAs) was also analyzed in the SCP and deep capillary plexus of OCTA and compared with FA. Patients and methods The study included 40 eyes of patients with NPDR and 20 eyes of volunteers as control. FA, OCT, and OCTA were done for all 40 eyes of NPDR, and only OCTA was done for the control group. OCTA parameters were as follows: ‘vessel density (mm/mm2), CP (%) (in SCP), and FAZ area (mm2) in SCP of macular area.' OCTA was performed using both 3×3 mm and 6 × 6 mm scans of the OCTA and with production of an OCT macular map. Digital color fundus photography and FA photographs were analyzed in relation to NPDR with evaluation of;Deg;MA;Deg;s, FAZ appearance, and late dye leakage. For;Deg;MA;Deg; counting, a 3×3 mm section centered on the fovea was manually delimited on FA images. Results MA count comparison between FA and OCTA (SCP and deep capillary plexus) showed highly a statistically significant differences between them, with P value less than 0.001 in all cases. DMI appeared early in all eyes with NPDR, presented with vessel density, CP, and the FAZ area in the SCP in both groups of patients with NPDR (in group A without DME and in group B with DME), with no significant statistical difference between the two groups of NPDR. Group A had a mean±SD vessel density of 9.95±2.805 mm/mm2, mean±SD of CP 18.97±4.754%, and mean±SD FAZ size of 0.59±0.228 mm2, whereas in group B, mean±SD vessel density was 10.19±3.152 mm/mm2, mean±SD CP was 20.14±6.131%, and mean±SD FAZ size was 0.63±0.270 mm2. When comparing groups A and B of patients with NPDR with the control group (group C), the control group showed a mean±SD vessel density of 13.23±2.454 mm/mm2, mean±SD of CP 27.89±5.627%, and mean±SD FAZ size of 0.36±0.097 mm2. A highly significant difference was found between patients with NPDR (both groups A and B) and healthy participants (group C). Conclusions MAs are more prominent in FA than in OCTA. Superficial vessel density and CP of macular region in NPDR eyes with and without DME are both decreased, in correlation to control group. The FAZ region of patients with NPDR is also enlarged when compared with healthy participants. CP and vessel density cannot be evaluated by FA, which is an advantage of OCTA over FA, but by using FA, we can evaluate the periphery, which cannot be evaluated by OCTA up till now.

Associations Between Diabetic Retinal Microvasculopathy and Neuronal Degeneration Assessed by Swept-Source OCT and OCT Angiography.

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.

Foveal avascular zone analysis by optical coherence tomography angiography in patients with type 1 and 2 diabetes and without clinical signs of diabetic retinopathy.

To analyze the early macular microvascular alterations in patients with type 1 and 2 diabetes mellitus (DM) without diabetic retinopathy (DR), using optical coherence tomography angiography (OCT-A), and compare these with nondiabetic patients. This prospective study involved 93 patients with type 1 diabetes (DM1), 104 patients with type 2 diabetes (DM2) without signs of DR, and 71 healthy subjects for the control group. The foveal avascular zone (FAZ) area and the vessel density (VD) at the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were evaluated. The SCP and DCP FAZ areas were significantly larger in the DM1 group in comparison with the controls (p = .001), while no significant differences were observed between the DM2 group and the healthy control group (p = .12). Additionally, no significant differences in FAZ area were found between the DM1 and DM2 groups (p = .26). The VD was significantly reduced in DM1 and DM2 groups compared to controls. A direct correlation was found between the duration of diabetes and SCP FAZ area (r = 0.44; R2 = 0.19; p = .0001). Statistically significant differences in the FAZ area at SCP and DCP were observed when comparing patients with a diabetes duration > 10years and < 10years in the DM2 group (p = .0001, respectively) and only in the FAZ area at the DCP in the DM1 group (p = .0001). Diabetic patients without DR demonstrate early microvascular alteration in the macular area on OCT-A, which is more pronounced in type I DM, and correlates with the duration of the disease.

Functional and Structural Outcomes at the Foveal Avascular Zone with Optical Coherence Tomography Following Macula off Retinal Detachment Repair.

BackgroundVisual recovery following macula involving rhegmatogenous retinal detachment remains poorly understood. The aim of this work is to correlate the functional and the anatomical changes in retinal vasculature in the foveal avascular zone using optical coherence tomography angiography (OCTA) after successful retinal reattachment repair and correlate this data with retinal thickness and post-operative visual recovery.MethodsA prospective, comparative observational study of 28 eyes of 14 patients with 14 eyes undergoing macula off retinal detachment repair with pars plana vitrectomy, endo-laser and silicone oil-based tamponade compared with 14 fellow healthy eyes at 1, 6 and 12 weeks post-operative period. The study was conducted at the Research Institute of Ophthalmology, Giza, Egypt between February 2018 and August 2018.ResultsThe foveal avascular zone (FAZ) area in the patients group was not significantly different compared to the control group and was found to be negatively correlated with the central retinal thickness in both the study and control group. The superficial capillary plexus (SCP) area at the FAZ was significantly larger than the deep capillary plexus (DCP) area at the FAZ in both the study and control group over the follow-up period. The DCP area at the FAZ was significantly larger at the 3rd follow-up than the 1st follow-up. The SCP FAZ area was significantly larger than the DCP FAZ area in both the study and control group over the follow-up period. BCVA was found to be negatively correlated to the retinal thickness of the temporal 3 mm paracentral quadrant with no correlation with central foveal thickness (CFT) and the FAZ area.ConclusionOptical coherence tomography (OCT) and OCTA are valuable noninvasive imaging tools to monitor and predict the structural changes at the foveal avascular zone during the recovery phase after successful retinal reattachment involving macula.

Repeatability of Manual Measurement of Foveal Avascular Zone Area in Optical Coherence Tomography Angiography Images in High Myopia

PurposeTo analyze the repeatability of manual measurement of foveal avascular zone (FAZ) area in an optical coherence tomography angiography (OCTA) image in high myopia.MethodsThis study comprised patients with high myopia and controls. Two consecutive FAZ areas of the superficial and deep capillary plexus were obtained using OCTA. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) were assessed, and univariate and multivariate generalized linear mixed models were conducted to identify factors related to repeatability.ResultsThirty eyes with high myopia and 34 eyes of healthy subjects were included in the study. The mean age in high myopia and control subjects was 55.5 and 60.8 years, respectively, the mean spherical equivalent was −9.98 and −0.55 diopters, and the mean axial length was 28.0 and 23.9 mm. The ICCs of FAZ area of the superficial capillary plexus (SCP) were 0.891 and 0.919, while the CVs were 8.8% and 8.5%. In measurement of the deep capillary plexus, the ICCs were 0.788 and 0.907, while the CVs were 11.2% and 11.0%, which were acceptable but exhibited lower repeatability than those of SCP. Multivariate analyses showed that older age (p = 0.030) and greater axial length (p = 0.005) were significantly associated with lower repeatability of SCP FAZ area measurements. In addition, greater axial length (p = 0.044) was a significant factor for lower repeatability of deep capillary plexus FAZ area measurements.ConclusionsManual measurement of FAZ area using OCTA exhibited relatively good repeatability for high myopia. Age and axial length affected repeatability and should be considered when analyzing FAZ areas in high myopia patients.

Correlation between Findings of Optical Coherence Tomography And Optical Coherence Tomography Angiography in Patients with Diabetic Macular Ischemia

AbstractBackground: Diabetic Macular Ischemia (DMI) is a variant of diabetic maculopathy that can be overlooked but has serious implication on management of Diabetic Retinopathy (DR) and Diabetic Macular Edema (DME).Aim of Study: The aim of the study was to study the findings of OCT (optical coherence tomography) and OCTA (optical coherence tomography angiography) in patients with DMI and correlate them.Patients and Methods: A cross sectional study that included 30 eyes: 20 eyes with DMI as diagnosed by FFA (fundus fluorescein angiography) and 10 healthy eyes as control. Both groups underwent OCT and OCTA imaging. OCT images were assessed for thickness and structural abnormalities. Macular perfusion was quantified using OCTA images by 2 parameters: FAZ (foveal avascular zone) area and VAD (vessel area density) at 2 levels; SCP (superficial capillary plexus) and DCP (deep capillary plexus).Results: A statistically significant difference as regard values of FAZ area and VAD in both SCP and DCP, using OCTA, was found between patients and control groups.There was a statistically significant correlation between the retinal thickness of ischemic macular areas and SCP FAZ area, SCP VAD and DCP VAD. DRIL (disorganization of retinal inner layers) was found in 55% of patients. A statistically significant correlation was found between the presence of DRIL and both SCP FAZ area and SCP VAD (r=0.755, pConclusion: OCTA is able to detect and quantify DMI and it can substitute FFA for that purpose. OCT can detect ischemic areas of the macula as these areas appear to be thinner than normal and to show disorganization of its inner retinal layers.

Correlation between foveal avascular zone size and foveal morphology in patients with idiopathic macular epiretinal membrane

Objective To analyze the correlation between foveal avascular zone (FAZ) size and foveal morphology in patients with idiopathic macular epiretinal membrane (IMEM) using OCT angiography (OCTA). Methods A retrospective case series study contained of 54 eyes of 54 patients affected with IMEM (IEM group) and 50 eyes of 50 normal persons as the control group. The BCVA was measured using the international standard visual acuity chart, and the results were converted to the logMAR visual acuity. The FAZ areas were evaluated with OCTA in both the superficial and deep capillary plexus layers by using 3 mm×3 mm images of the macular. The central macular thickness (CMT), inner retinal layer thickness (IRT), outer retinal layer thickness (ORT), subfoveal choroidal thickness (SFCT), and the status of ellipsoid zone (EZ) were assessed with spectral-domain optical coherence tomography. The differences of FAZ areas between the two groups were analyzed. The correlative analysis was performed to investigate the relationship between areas and foveal morphology. Results Compared with control group, the FAZ area in superficial and deep capillary plexus in the IMEM group were significantly smaller (t=−29.095, −28.743; P<0.001, <0.001); the mean CMT, IRT, ORT and SFCT were significantly thickening in the IMEM group (Z=−8.784, −8.524, −7.709, −7.535; P<0.001,<0.001, <0.001, <0.001). In the IMEM group, the FAZ area in superficial capillary plexus correlated inversely with the CMT, IRT, and the integrity of EZ (r=−0.464, −0.536, −0.293; P<0.001, <0.001, 0.039), no significant correlation of superficial plexus FAZ areas with ORT and SFCT (r=−0.218, −0.165; P=0.172, 0.157). The FAZ area in deep capillary plexus correlated inversely with the CMT, IRT, and the integrity of EZ (r=−0.306, −0.694, −0.468; P=0.037, <0.001, <0.001), no significant correlation with ORT and SFCT (r=−0.242, −0.227; P=0.079, 0.094). Conclusions The FAZ areas is significantly decreased in IMEM eyes compared with normal eyes. Both superficial and deep FAZ area are correlated with the CMT, IRT, and the integrity of EZ. Key words: Macula lutea; Membranes; Tomography, optical coherence; Foveal avascular zone

Sex-Related Variations of Retinal and Choroidal Thickness and Foveal Avascular Zone in Healthy and Diabetic Children Assessed by Optical Coherence Tomography Imaging

Purpose of the Study: The aim of this study was to investigate the presence of gender differences in the chorioretinal microvasculature of children with and without vascular pathology. Methods: Healthy and type 1 diabetic children without diabetic retinopathy underwent optical coherence tomography angiography (OCTA) and structural OCT. We measured the foveal avascular zone (FAZ) area in the superficial capillary plexus (SCP) and deep CP (DCP), central retina, and choroid thickness. Results: OCTA examination was conducted in 112 diabetic and 30 healthy children, and structural OCT in 121 diabetic children and 32 controls. DCP FAZ area in boys was significantly smaller than in girls both in diabetics (p = 0.0010) and healthy children (p = 0.0302). In diabetics, SCP FAZ area was significantly smaller in boys (p = 0.0006), analogically to controls (p = 0.0870). Central retinal thickness was significantly greater in boys compared with girls in diabetics (p = 0.0001) and controls (p = 0.1008). Conclusion: Significant differences exist in the FAZ area and retinal thickness between sexes, likely representing physiological differences. Different norms must be used for boys and girls regardless of diabetic status.

Early microvascular retinal changes in optical coherence tomography angiography in patients with type 1 diabetes mellitus.

Diabetic retinopathy (DR) can lead to significant vision loss and blindness and has a particularly high prevalence in patients with type 1 diabetes (DM1). In this study, we investigate quantitative differences in optical coherence tomography angiography (OCTA) data between DM1 patients with no or mild signs of retinopathy and non-diabetic subjects. Optical coherence tomography angiography (OCTA) imaging was performed on DM1 patients with no or mild nonproliferative diabetic retinopathy and healthy, age-matched controls. Parafoveal vessel density and foveal avascular zone (FAZ) area in the deep capillary plexus (DCP) and superficial capillary plexus (SCP) were calculated with automated quantification software and compared between patient cohorts. A significant decrease in parafoveal vessel density was seen in the DCP of DM1 patients compared to non-diabetic controls (57.0±3.3% versus 60.7±2.4%, p<0.001). There was no significant difference in SCP parafoveal vessel density, DCP FAZ area, or SCP FAZ area between cohorts. M1 patients with no or mild signs of retinopathy have reduced parafoveal vessel density in the DCP on OCTA when compared to non-diabetic controls. These OCTA findings suggest that parafoveal capillary nonperfusion is an early process in DM1-related retinal changes and occurs initially at the level of the DCP. Further investigation is needed to understand the prognostic role of these vascular changes.