Foveal Avascular Zone Area Research Articles

Correlation between optical coherence tomography angiography-based data and postoperative visual acuity in patients that underwent surgery for macula-on RRD and macula-off RRD

Background: Despite advances in surgical techniques for rhegmatogenous retinal detachment (RRD) repair, patients are still at high risk for low functional outcomes. Given the above, it is important to find reasons for disappointment at the outcomes of vitreoretinal surgery for RRD. Impaired retinal microcirculation is a possible cause of insufficiently good functional outcomes in surgery for RRD. Purpose: To compare postoperative optical coherence tomography angiography (OCTA)-based changes in retinal microcirculation in the eyes of patients that underwent surgery for macula-on RRD versus the eyes of patients that underwent surgery for macula-off RRD and (2) to establish a relationship between OCTA data and best-corrected visual acuity (BCVA). Material and Methods: This prospective study included 116 patients. Of these, 65 underwent surgery for macular-on RRD (group 1) and 51, surgery for macular-off RRD (group 2). OCTA-based retinal vasculature parameters (foveal avascular zone (FAZ) area, parafoveal superficial capillary plexus (SCP) density and deep capillary plexus (DCP) density, vessel diameter, and vessel tortuosity index (VTI)) and their correlation with BCVA were assessed. Follow-up duration was 12 months. Results: In group 1, there was a negative correlation between the FAZ area and the macular thickness (r = - 0.299, p = 0.025) at month 12. The final BCVA was associated with the parafoveal DCP density (r = - 0.340, p = 0.010) and FAZ area (r= 0.390, p = 0.003). At 12 months, in group 2, the BCVA negatively correlated with the FAZ area (r = - 0.408, p = 0.012) and parafoveal SCP density (r = - 0.451, p = 0.005). In addition, there was a negative correlation between the parafoveal DCP density and the postoperative BCVA (r = - 0.418). There was no correlation between the FAZ area and the macular thickness (r = - 0.282, p = 0.080). Conclusion: The poorer vessel tortuosity index and parafoveal vessel density and diameter, the lower was postoperative visual acuity.

Does thalassemia truly cause microvascular changes without us noticing? An optical coherence tomography angiography study of the children with beta-thalassemia.

It was aimed to evaluate the retinochoroidal microvascular alterations of pediatric beta-thalassemia patients and investigate the effect of blood transfusion on perfusion among transfusion-dependent thalassemia (TDT), by means of optical coherence tomography angiography (OCTA). In this multicentered, prospective, cross-sectional study, 56 TDT, 14 non-TDT (NTDT), and 63 healthy children were evaluated. The vessel density (VD) in superficial capillary plexus (SCP), deep capillary plexus, radial peripapillary capillarynetwork, choriocapillaris, and the foveal avascular zone area (FAZ) were evaluated by OCTA. Before and after transfusion values ​​of the TDT group were compared, and correlations were made with blood values ​​and iron accumulation. Foveal and parafoveal zones were significantly thinner among TDT patients, with larger FAZ area. Macula VD of SCP and ppVD was lowest in NTDT group. In the TDT group, a decrease in retinal nerve fiber thickness and ppVD values was detected ​​after transfusion. A negative significant relationship was found between both hemoglobin (Hb), hematocrit (Htc), and ppVD. OCTA provides a better insight into retinal and choriocapillaris vascular impairment influenced by tissue hypoxia and oxidative stress in different clinical phenotypes of beta-thalassemia.

Comparison of posterior segment ocular parameters of Familial mediterranean fever with homozygous M694V mutation and carriers with heterozygous M694V mutation in children

PurposeThe aim of this study is to comparatively evaluate the posterior segment ocular parameters of Familial Mediterranean fever (FMF) patients, asymptomatic FMF carriers, and the healthy controls in the pediatric age group. MethodsThe study included 30 FMF patients with homozygous M694V mutation in remission under colchicine therapy, 12 asymptomatic FMF carriers with heterozygous M694V mutation, and 41 age-sex-matched healthy controls. All patients underwent detailed eye examination, and peripapillary retinal nerve fiber layer (pRNFL) thickness, central macular thickness (CMT), subfoveal choroidal thickness (SCT), macular vascular densities, and foveal avascular zone (FAZ) areas were measured using swept-source optical coherence tomography angiography. ResultsIn this study, the mean pRNFL thickness was statistically significantly thinner (p = 0.010) in the FMF patients group compared to the FMF carriers group and the healthy control group, especially in the inferior quadrant of pRNFL (p = 0.042). The CMT in asymptomatic FMF carriers group was statistically significantly thicker than in FMF patients group (p = 0.037), especially the superior and inferior quadrants of macula were affected (p = 0.024; p = 0.020, respectively). In addition, this study showed that the changes of pRNFL thickness and CMT in pediatric patients with FMF were moderately correlated with the duration of diagnosis. There was no significant difference between the groups in terms of macular vascular densities and FAZ values. ConclusionFMF is a hereditary autoinflammatory disease that causes multi-organ involvement, and this study showed that posterior segment ocular parameters could be affected not only in FMF patients but also in asymptomatic FMF carriers.

Retinal and choroidal microvascular changes during pregnancy detected with OCTA

ObjectifExaminer les variations du débit sanguin dans la choroïde et la rétine de même que l’épaisseur de ces structures grâce à la tomographie par cohérence optique (OCT, pour optical coherence tomography) et à l'angiographie-tomographie par cohérence optique (OCTA, pour optical coherence tomography angiography) pendant la grossesse. NatureÉtude cas-témoins prospective réalisée entre juin 2020 et juin 2021. MéthodesLa présente étude prospective portait sur 41 yeux de 41 femmes enceintes et sur 45 yeux de 45 femmes non enceintes en bonne santé. La pression de perfusion oculaire, l’épaisseur de la rétine, l’épaisseur de la choroïde, l'aire de la zone fovéale avasculaire (ZFA), les plexus capillaires superficiel et profond (PCS et PCP, respectivement), la densité vasculaire (DV) et la DV de la choriocapillaire (CC) ont été évalués par OCT et OCTA. RésultatsOn n'a pas observé de différence significative au chapitre de la pression de perfusion oculaire, de l’épaisseur de la rétine et de l’épaisseur de la choroïde pendant la grossesse. L'aire de la ZFA augmentait à mesure que la grossesse progressait (p = 0,011). Pendant le premier trimestre, l'aire de la ZFA était significativement plus petite que chez les patientes du groupe témoin (p = 0,029). Cependant, on a noté une diminution de la DV du PCS et du PCP pendant le troisième trimestre et une augmentation de la DV de la CC pendant toute la grossesse (p = 0,01; p < 0,001 et p < 0,001, respectivement). Il s'est produit une hausse de la DV moyenne tant dans le PCS que dans le PCP pendant le deuxième trimestre (p = 0,02 et p = 0,027, respectivement). La DV du PCS et du PCP était significativement plus élevée pendant le deuxième et le troisième trimestre que chez les témoins. Enfin, une élévation significative de la DV de la CC a été enregistrée pendant la grossesse. ConclusionIl s'agit de la première étude prospective publiée à faire appel à l'OCTA pour évaluer ces mesures pendant les trois trimestres de la grossesse. Nous avons observé des modifications microvasculaires significatives dans la rétine et la choroïde entre les différents trimestres de la grossesse, de même qu'entre les femmes enceintes et les femmes en bonne santé qui n’étaient pas enceintes.

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.

Morphologic analysis of the foveal avascular zone for prediction of postoperative visual acuity in advanced idiopathic epiretinal membrane

To investigate the preoperative morphology of the foveal avascular zone (FAZ) for prediction of the postoperative visual acuity in advanced idiopathic epiretinal membrane (ERM). 28 patients (28 eyes) with unilateral idiopathic ERM who underwent pars plana vitrectomy with internal limiting membrane peeling were included. Superficial FAZ was measured preoperatively in both eyes using optical coherence tomography angiography. Area, perimeter, and circularity of FAZ were achieved, and the differences between the ERM eyes and the contralateral eyes were evaluated to analyze the degree of FAZ distortion in diseased eyes. The best-corrected visual acuity (BCVA) and central foveal thickness (CFT) were measured at baseline and more than 6 months after surgery. The correlations of the preoperative FAZ with BCVA and CFT were assessed. The FAZ in the eyes with ERM was significantly reduced, and the BCVA was significantly correlated with the FAZ area (FAZa) (P = 0.001) and the FAZ perimeter (FAZp) (P < 0.001) before surgery. LogMAR BCVA and CFT were significantly improved from 0.550 ± 0.221 to 0.354 ± 0.229 (P = 0.008), and from 524.393 ± 93.575 µm to 400.071 ± 75.979 µm (P < 0.001) after surgery. The preoperative FAZa and FAZp were significantly associated with letter score gain (P < 0.001, P < 0.001) and the postoperative final BCVA (P = 0.026, P = 0.006). The preoperative FAZp had correlation with ratio of postoperative to preoperative CFT (P = 0.016). The preoperative FAZp is a predictor of visual acuity and morphological prognosis after surgery in advanced idiopathic ERM.

Efficacy and safety of subthreshold micropulse laser in the treatment of acute central serous chorioretinopathy.

To analyze the efficacy and safety of subthreshold micropulse laser (SML) in the treatment of acute central serous chorioretinopathy (CSC). This is a retrospective case analysis study. Totally 58 eyes of 58 patients were enrolled, and they were divided into different groups. And 39 patients were treated with SML (SML group) and 19 patients were only observed (observation group). The follow-up period was 3mo after diagnosis. The best corrected visual acuity (BCVA), central retinal thickness (CRT), superficial retinal vascular density (SRVD), deep retinal vascular density (DRVD), the superficial and deep foveal avascular zone (FAZ) area, retinal light sensitivity (RLS), perfusion area of choroidal capillary layer (CCL), subfoveal choroidal thickness (SFCT) and fundus autofluorescence (FAF) were investigated. The BCVA, CRT, SRVD, DRVD, the superficial and deep FAZ area, RLS, SFCT of SML group were significantly improved at 3mo (all P<0.05). In the observation group, only CRT, DRVD and SFCT were improved (all P<0.05). Other research items in the observation group were not significantly different from baseline (all P>0.05). At the last follow-up, the BCVA and RLS in the SML group were better than those in the observation group, and CRT was lower, SRVD and DRVD, perfusion area of CCL were larger (all P<0.05). On FAF, no change of treatment spots was found after treatment. No structural laser damage was observed on optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA), and no choroidal neovascularization was observed. SML treatment of acute CSC can improve BCVA, RLS, and perfusion area of CCL, reduce CRT, increase SRVD and DRVD, and is safe.

Optical coherence tomography angiography aspects of the retinal and optic disc microvascular morphology in erythemato-telangectatic rosacea

BackgroundTo investigate retinal and optic disc (OD) microvascular morphological changes in erythemato-telangiectatic rosacea (ETR) patients using optical coherence tomography angiography (OCTA), and compare the findings to age- and gender-matched healthy individuals. MethodsThis study included newly diagnosed 31 ETR patients (31 right eyes, group 1) who were clinically diagnosed by two experienced dermatologists. A control group had 32 healthy individuals (32 right eyes, group 2). Demographic data, including age and gender were collected, followed by a thorough ophthalmologic exam. A 6 × 6 mm macular OCTA analysis of superficial and deep capillary plexus (SCP and DCP) vessel densities (VDs), as well as foveal avascular zone (FAZ) area, FAZ perimeter (PERIM), foveal VDs 300 µm area around FAZ (FD-300), and flow areas in the outer retinal and choriocapillaris, was then performed. ResultsMean age in groups 1 and 2 was 43.70 ± 13.02 and 43.62 ± 12.30 years, respectively (p=0.979). Male-to-female ratio in group 1 was 4:27 and 4:28 in group 2. Capillary flow analysis revealed slightly higher values in group 1 than in group 2, with the former having a significantly higher select area in the outer retinal layer (p=0.001) and flow area in the choriocapillaris (p=0.002). Despite slightly higher values in group 1, there were no significant differences in SCP and DCP VDs (p > 0.05), FAZ area (p=0.471), PERIM (p=0.778), or FD-300 (p=0.527). ConclusionsETR appears to be associated with posterior segment changes, especially retinal microvascular morphology, even in asymptomatic ocular conditions. Given the disease's high rate of misdiagnosis, understanding rosacea-induced ocular manifestations is critical for ophthalmologists

The Characteristic of Optical Coherence Tomography Angiography and Retinal Arteries Angle in Familial Exudative Vitreoretinopathy with Inner Retinal Layer Persistence

Purpose To compare the angle of retinal arteries and macular vessel density and foveal avascular zone (FAZ) in early stage familial exudative vitreoretinopathy (FEVR) patients with inner retinal layer (IRL) persistence with FEVR patients without IRL persistence and normal people. Methods This study enrolled 113 early stage FEVR patients and 55 age-matched normal subjects. FEVR patients were divided into IRL group and non-IRL group based on the presence or absence of IRL in fovea. The angle of superior temporal and inferior temporal branch retinal arteries on ultra-wide-field fundus images were measured. Superficial and deep vessel density of whole image, fovea and parafovea, the area and perimeter of FAZ, A-circularity index (AI, perimeter/standard circle perimeter with equal area) and vessel density around the 300-μm width of the FAZ (FD), central macular thickness (CMT) on 3 mm × 3mm OCTA were measured. Results 30 FEVR patients in IRL group, 83 FEVR patients in non-IRL group, 55 normal people in control group were evaluated. BCVA were worst in IRL group (p < .001). The angle of retinal arteries was smaller in FEVR groups (p < .001) and were smallest in IRL group (p < .001). Superficial and deep vessel density of whole and parafovea area in FEVR patients were significantly lower than that in normal people (p < .05), AI were biggest (p = .01) and FD were smallest in IRL group (p < .001). CMT in IRL group were thicker than non-IRL group and control group (p < .05). Conclusion Worse BCVA, smaller angle of retinal arteries (more vessels traction), lower macular vessel density, smaller and more irregular FAZ and thicker CMT were observed in FEVR patients with IRL persistence even in early stage.

Right versus left eye asymmetry of microvasculature in diabetes revealed by optical coherence tomography angiography

In this study, we explored inter-ocular asymmetry (between the two eyes of the same patient) using optical coherence tomography angiography (OCTA) in patients with diabetes mellitus (DM) at different retinopathy stages. A total of 258 patients were divided into four groups: no DM, DM without diabetic retinopathy (DR), non-proliferative DR (NPDR), and proliferative DR (PDR). Superficial and deep vessel density (SVD, DVD), superficial and deep perfusion density (SPD, DPD), foveal avascular zone (FAZ) area, perimeter and circularity were calculated, and asymmetry index (AI) was used to evaluate the asymmetry of two eyes of the same subject. AIs of SPD, SVD, FAZ area and FAZ perimeter in the PDR group were larger than all other 3 groups (all p < 0.05). The AIs of DPD, DVD, FAZ area and FAZ perimeter in males were larger than in females (p = 0.015, p = 0.023, p = 0.006 and p = 0.017). Hemoglobin A1c (HbA1c) was positively correlated with AI of FAZ perimeter (p = 0.02) and circularity (p = 0.022). In conclusion, PDR patients’ eyes were significantly asymmetric in both vascular density and FAZ metrics. Male sex and HbA1c are risk factors that influenced symmetry. This study highlights that right-left asymmetry should be taken into account in DR-related studies, particularly those analyzing microvascular changes with OCTA.

Association of OCT and OCT angiography measures with the development and worsening of diabetic retinopathy in type 2 diabetes.

To assess if optical coherence tomography (OCT) and OCT angiography (OCTA) measures are associated with the development and worsening of diabetic retinopathy (DR) over four years. 280 participants with type 2 diabetes underwent ultra-wide field fundus photography, OCT and OCTA. OCT-derived macular thickness measures, retinal nerve fibre layer and ganglion cell-inner plexiform layer thickness and OCTA-derived foveal avascular zone area, perimeter, circularity, vessel density (VD) and macular perfusion (MP) were examined in relation to the development and worsening of DR over four years. After four years, 206 eyes of 219 participants were eligible for analysis. 27 of the 161 eyes (16.7%) with no DR at baseline developed new DR, which was associated with a higher baseline HbA1c and longer diabetes duration. Of the 45 eyes with non-proliferative DR (NPDR) at baseline, 17 (37.7%) showed DR progression. Baseline VD (12.90 vs. 14.90 mm/mm2, p = 0.032) and MP (31.79% vs.36.96%, p = 0.043) were significantly lower in progressors compared to non-progressors. Progression of DR was inversely related to VD ((hazard ratio [HR] = 0.825) and to MP (HR = 0.936). The area under the receiver operating characteristic curves for VD was AUC = 0.643, with 77.4% sensitivity and 41.8% specificity for a cut-off of 15.85 mm/mm2 and for MP it was AUC = 0.635, with 77.4% sensitivity and 25.5% specificity for a cut-off of 40.8%. OCTA metrics have utility in predicting progression rather than the development of DR in individuals with type 2 diabetes.

Differences in rate of change of retinal structural and microvasculature parameters in parkinson’s disease compared to controls

AbstractBackgroundPrior cross‐sectional studies have revealed decreased macular perfusion density (PFD) and increased peripapillary PFD in Parkinson’s disease (PD). We assess longitudinal rate of change of retinal microvascular and structural parameters in PD vs controls with normal cognition.MethodSubjects were imaged using Zeiss Cirrus HD‐5000 AngioPlex. Those with confounding medical or ocular comorbidities were excluded. Superficial capillary plexus (SCP) PFD and vessel density (VD) were assessed within ETDRS 6×6 circle, inner ring, outer ring and 3×3 circle and inner ring. SCP foveal avascular zone (FAZ) area was assessed. PFD, VD, FAZ, peripapillary retinal nerve fiber layer (RNFL), ganglion cell‐inner plexiform layer (GCIPL), and central subfield thickness (CST) were measured at 2 time points 1 year apart. Rate of change per year was calculated. Generalized estimating equations analyzed associations between rate of change of imaging parameters and PD.Result74 eyes of 40 patients with PD (60% male, mean age 67.47.9 years) &amp; 149 eyes of 78 controls (28% male, mean age 70.35.8 years) were included. No demographic differences were observed between groups except higher proportion of females in controls (p = 0.001). PD had a greater decline in PFD in 6×6 circle (mean change per year = 0.021, control = 0.00, p = 0.001), 6×6 inner ring (PD = 0.018, control = 0.001, p = .007), 6×6 outer ring (PD = 0.022, control = 0.00, p = 0.001), 3×3 circle (PD = 0.016, control = 0.002, p&lt;.001), 3×3 inner ring (PD = 0.016, control = 0.002, p&lt;0.001). PD had greater decline in VD in 6×6 circle (mean change per year in PD = 0.72/mm, control = 0.054/mm, p = 0.006), 6×6 inner ring (PD = 0.636/mm, control = 0.048/mm, p = 0.03), 6×6 outer ring (PD = 0.746/mm, control = 0.054/mm, p = 0.005), 3×3 circle (PD = 0.939/mm, control = 0.006/mm, p&lt;0.001), 3×3 inner ring (PD = ‐0.942/mm, control = 0.013/mm, p&lt;0.001). PD had greater decrease in GCIPL (mean change per year in PD = 0.403µm, control = 0.128µm control, p = 0.01). There were no significant differences in rate of change in FAZ area, RNFL thickness, CST, and no significant differences in rate of change when stratified by PD severity.ConclusionPD may be associated with more rapid loss of retinal microvascular perfusion and vessel densities and more rapid thinning of GCIPL compared to normal aging in controls with normal cognition.

Intrasession Repeatability of OCT Angiography Parameters in Neurodegenerative Disease.

To assess the intrasession repeatability of macular OCT angiography (OCTA) parameters in Alzheimer's disease (AD), mild cognitive impairment (MCI), Parkinson's disease (PD), and normal cognition (NC). Cross sectional study. Patients with a clinical diagnosis of AD, PD, MCI, or NC were imaged. Images with poor quality and of those with diabetes mellitus, glaucoma, or vitreoretinal disease were excluded from analysis. All participants were imaged using the Zeiss Cirrus HD-5000 with AngioPlex (Carl Zeiss Meditec, Software Version 11.0.0.29946) and repeat OCTA images were obtained for both eyes. Perfusion density (PFD), vessel density (VD), and Foveal avascular zone (FAZ) area were measured from 3×3 mm and 6×6 mm OCTA images centered on the fovea using an ETDRS grid overlay. Intraclass correlation coefficients were used to quantify repeatability of PFD, VD, and FAZ area measurements obtained from imaging. 3×3 mm scans of 22 AD, 40 MCI, 21 PD, and 26 NC participants and 6×6 mm scans of 29 AD, 44 MCI, 29 PD, and 30 NC participants were analyzed. Repeatability values ranged from 0.64 (0.49-0.82) for 6×6 mm PFD in AD participants to 0.87 (0.67-0.92) for 3×3 mm PFD in AD participants. No significant differences were observed in repeatability between NC participants and those with neurodegenerative disease. Overall, similar OCTA repeatability was observed between NC participants and those with neurodegeneration. Regardless of diagnostic group, macular OCTA metrics demonstrated moderate to good repeatability. The authors have no proprietary or commercial interest in any materials discussed in this article.

Оценка макулярного кровотока с помощью оптической когерентной томографии-ангиографии у беременных женщин, страдающих сахарным диабетом

Purpose. To study retinal blood flow in pregnant women with disorders of carbohydrate metabolism using optical coherence tomography angiography (OCTA) in order to determine the criteria for the manifestation and progression of diabetic retinopathy (DR). Material and methods. 203 pregnant women in the third trimester were examined: 24 – with type 1 and 2 diabetes (T1D and T2D), 143 – with gestational diabetes (GD), and 36 apparently healthy women with physiological pregnancy, who consisted the control group. OCTA imaging was performed using the RTVue XR Avanti OCT 6 mm × 6 mm «Angio Retina» scan protocols (Optovue, USA). The whole image vessel density (wiVD), foveal vessel density (FVD), and foveal avascular zone (FAZ) area in the superficial capillary plexus were studied. Results. FVD in pregnant women with diabetes was significantly less than in pregnant women with GD and in the control group. In this connection, it can be assume changes of the retinal microvascular regulation, due to chronic disorders of carbohydrate metabolism in patients with diabetes, and development of microangiopathy. Enlargement of FAZ area and decrease of wiVD were revealed in patients with DR, relative to datas obtained in the group of pregnant women with diabetes and absence of DR, in the absence of differences in FVD indexes. In 2 patients with T1D and the absence of ophthalmoscopic signs of DR, OCTA revealed areas of nonperfusion in the posterior pole of the eye. Conclusion. OCTA helps to identify areas of retinal nonperfusion in the posterior pole of the eye in pregnant women with diabetes in the absence of ophthalmoscopic signs of DR and allows determining objective indications for timely retinal laser coagulation. Keywords: optical coherence tomography angiography, pregnancy, diabetic retinopathy, gestational diabetes, foveal avascular zone, retinal blood flow

Deep Capillary Plexus as Biomarker of Peripheral Capillary Nonperfusion in Central Retinal Vein Occlusion.

To identify the vascular biomarkers of peripheral capillary nonperfusion in patients affected by naive central retinal vein occlusion (CRVO), and to analyze their changes over the follow-up. Consecutive prospective case series with a planned follow-up of 2years. Thirty-five patients affected by CRVO and 35 healthy gender- and age-matched subjects were enrolled in the study. Ophthalmic examination included best corrected visual acuity (BCVA), ultrawidefield fluorescein angiography (UWFFA), OCT, and OCT angiography (OCTA). Vessel density (VD) at the superficial capillary plexus and deep capillary plexus (DCP) were calculated on OCTA images. The ischemic index (ISI) was calculated on UWFFA. The mean baseline ISI was 37%, increasing to 40% at the end of the follow-up, whereas it was 4.9% in the patients' fellow eyes and 4.5% in the control group with no change over the follow-up. OCT angiography revealed VD reduction in the DCP, considering both 3×3 mm and 12×12 mm scans. The correlation analyses revealed that DCP VD was the only parameter showing a statistically significant correlation with the foveal avascular zone (FAZ) area, BCVA, and ISI. Deep capillary plexus VD impairment is detectable in all CRVO cases, variably involving both the central retina (with enlarged FAZ) and the periphery (with VD reduction in the peripheral retina). The severity of DCP VD reduction has correlates with various clinical markers. Deep capillary plexus VD may represent a crucial biomarker to characterize CRVO, and further studies are necessary to identify the cutoff thresholds for the different clinicalmanifestations.

The Association of Neovascularization With Optical Coherence Tomography Angiography Parameters in Proliferative Diabetic Retinopathy.

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.

Effect of oral contraceptive pills on the retinal microvascular structure: An optical coherence tomography angiography study

BackgroundTo investigate the effect of oral contraceptive pills (OCPs) on foveal avascular zone (FAZ), peripapillary capillary plexus, and superficial and deep capillary plexus (SCP and DCP) measurements. MethodsThis cross-sectionally designed study included 32 healthy female participants using OCPs (3 mg drospirenone and 0.03 mg ethinylestradiol) for at least one year for contraception and 32 healthy controls that did not use any drugs. All subjects were evaluated using optical coherence tomography angiography (OCTA). Using OCTA, the measurements of SCP, DCP, radial peripapillary capillary (RPC) vessel density; FAZ area and perimeter; acircularity index (AI); and foveal density (FD) were undertaken. Each participant's measurements were taken while they were in the follicular phase of their menstrual cycles (day 3). ResultsAge and body mass index did not significantly differ between the groups (p = 0.56 and p = 0.15, respectively). The DCP vessel densities in all the regions were lower in the OCP group (p<0.05 for all). The vessel densities of SCP and RPC, FAZ area and perimeter, AI, and FD were similar between the two groups (p>0.05 for all). ConclusionWe determined that the DCP vessel density was reduced in women using this drug. OCPs can cause changes in retinal microvascular structures. Therefore, OCTA can be used in the follow-up of healthy women using OCP.

Macular vascular features of different types of diabetic macular edema using ocular coherence tomography angiography- a comparative study

BackgroundTo compare the microvascular features of different subtypes of diabetic macular edema (DME) by optical coherence tomography angiography (OCTA).MethodsA cross-sectional study including treatment-naive patients with DME. Eyes were divided according to optical coherence tomography determined morphology into two groups: cystoid macular edema (CME) and diffuse retinal thickening (DRT), with further subdivision according to the presence of subretinal fluid. All patients underwent 3 × 3 and 6 × 6 mm OCTA scans of the macula to compare the foveal avascular zone (FAZ) area, vascular density (VD) of the superficial (SCP) and deep (DCP) capillary plexus and choriocapillaris flow (CF). Laboratory findings (HbA1C and triglyceride levels) were also correlated with the OCTA findings.ResultsThe study included 52 eyes, 27 had CME and 25 had DRT. There were no significant differences between the VD of the SCP (p = 0.684) and DCP (p = 0.437), FAZ of SCP (p = 0.574), FAZ of DCP (p = 0.563) and CF (p = 0.311). Linear regression analysis revealed that DME morphology was the strongest predictor for BCVA. Other significant predictors included HbA1C and triglyceride levels.ConclusionThe morphology of DME, irrespective of SRF, was most significantly correlated with BCVA in treatment-naive patients and CME subtype could be an independent predictor of poor BCVA in patients with DME.

Retinal Microvascular Changes after Intravitreal Triamcinolone Acetonide in Diabetic Macular Edema.

Intravitreal injection of triamcinolone acetonide (TA) is essential for clinical treatment in patients who insufficiently respond to vascular endothelial factor inhibitors for diabetic macular edema (DME). The aim of this study was to investigate microvascular changes treated with TA using optical coherence tomography angiography (OCTA). After TA in twelve eyes of eleven patients with central retinal thickness (CRT), there was a 20% or more reduction observed. Visual acuity, the number of microaneurysms, vessel density, and the foveal avascular zone (FAZ) area were compared before and at 2 months after TA. At baseline, the number of microaneurysms was 2.1 ± 1.1 in the superficial capillary plexuses (SCP) and 2.0 ± 1.1 in the deep capillary plexuses (DCP), with a significant decrease post-treatment to 1.0 ± 1.0 for SCP and 0.8 ± 0.8 for DCP (SCP; p = 0.018, DCP; p = 0.008). There was significant enlargement of the FAZ area from 0.28 ± 0.11 mm2 to 0.32 ± 0.14 mm2 (p = 0.041). There was no significant difference in the visual acuity and vessel density of SCP and DCP. Results indicated that OCTA was useful for the evaluation of qualitative and morphological retinal microcirculation and that intravitreal TA may decrease microaneurysms.

A Reliable Criterion for the Correct Delimitation of the Foveal Avascular Zone in Diabetic Patients.

Manual segmentation of the Foveal Avascular Zone (FAZ) has a high level of variability. Research into retinas needs coherent segmentation sets with low variability. Retinal optical coherence tomography angiography (OCTA) images from type-1 diabetes mellitus (DM1), type-2 diabetes mellitus (DM2) and healthy patients were included. Superficial (SCP) and deep (DCP) capillary plexus FAZs were manually segmented by different observers. After comparing the results, a new criterion was established to reduce variability in the segmentations. The FAZ area and acircularity were also studied. The new segmentation criterion produces smaller areas (closer to the real FAZ) with lower variability than the different criteria of the explorers in both plexuses for the three groups. This was particularly noticeable for the DM2 group with damaged retinas. The acircularity values were also slightly reduced with the final criterion in all groups. The FAZ areas with lower values showed slightly higher acircularity values. We also have a consistent and coherent set of segmentations with which to continue our research. Manual segmentations of FAZ are generally carried out with little attention to the consistency of the measurements. A novel criterion for segmenting the FAZ allows segmentations made by different observers to be more similar.