Quantitative optical coherence tomography angiography assessments in the fellow eyes of those with central serous chorioretinopathy.

BACKGROUND: To analyze the vessel density (VD) of the retina and choriocapillaris (CC) layer and the structure of the foveal avascular zone (FAZ) in the fellow eyes of central serous chorioretinopathy (CSC) patients by using optical coherence tomography angiography (OCTA). METHODS: This was a case-control study. Unilateral CSC patients and age-matched healthy subjects were recruited from the Affiliated Eye Hospital of Wenzhou Medical University between July 2016 and July 2021. All eyes were divided into three groups: acute CSC (aCSC), chronic CSC (cCSC), and healthy controls. Both aCSC and cCSC were again divided into two subgroups: the affected eyes and the fellow eyes. In this study, all parameters of VD and FAZ were measured by self-software of OCTA. RESULTS: A total of 231 eyes of 137 subjects were included, with 47 aCSC patients, 47 cCSC patients, and 43 healthy controls. In the fellow eyes of CSC, the retinal VD was significantly lower (all P < 0.05), and the FAZ was significantly larger (all P < 0.05) in the cCSC group than in healthy controls, while no difference was detected in the CC layer. There was no significant difference between the aCSC group and healthy controls in all OCTA parameters. In the affected eyes of CSC, the superficial retinal vessel density (SRVD) was significantly higher (all P < 0.05) in healthy controls than in the aCSC and cCSC groups, while the deep retinal vessel density (DRVD) was significantly lower (all P < 0.05) and the FAZ was larger (all P < 0.05) in the cCSC group than in the aCSC group and healthy controls. A liner regression equation was established: Y (BCVA, best corrected visual acuity) = 3.692-0.036✱X1 (DRVD-Fovea)-0.031✱X2 (FD-300, vessel density around the 300 µm width of the FAZ), R2 = 0.427. CONCLUSION: Based on OCTA measurements, this study revealed that the retinal microvascular network was impaired even in the fellow eyes of those with cCSC, which should arouse attention to the observation of unilateral CSC.

The Framework of Quantifying Biomarkers of OCT and OCTA Images in Retinal Diseases.

Despite the significant advancements facilitated by previous research in introducing a plethora of retinal biomarkers, there is a lack of research addressing the clinical need for quantifying different biomarkers and prioritizing their importance for guiding clinical decision making in the context of retinal diseases. To address this issue, our study introduces a novel framework for quantifying biomarkers derived from optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images in retinal diseases. We extract 452 feature parameters from five feature types, including local binary patterns (LBP) features of OCT and OCTA, capillary and large vessel features, and the foveal avascular zone (FAZ) feature. Leveraging this extensive feature set, we construct a classification model using a statistically relevant p value for feature selection to predict retinal diseases. We obtain a high accuracy of 0.912 and F1-score of 0.906 in the task of disease classification using this framework. We find that OCT and OCTA's LBP features provide a significant contribution of 77.12% to the significance of biomarkers in predicting retinal diseases, suggesting their potential as latent indicators for clinical diagnosis. This study employs a quantitative analysis framework to identify potential biomarkers for retinal diseases in OCT and OCTA images. Our findings suggest that LBP parameters, skewness and kurtosis values of capillary, the maximum, mean, median, and standard deviation of large vessel, as well as the eccentricity, compactness, flatness, and anisotropy index of FAZ, may serve as significant indicators of retinal conditions.

Assessment of macular microvascular changes in children following treatment of anisometropic myopic amblyopia using optical coherence tomography angiography.

PURPOSE: To evaluate macular microvascular changes in the form of foveal avascular zone (FAZ) area and vessel density in the superficial, deep capillary plexuses, and choriocapillaris using optical coherence tomography angiography (OCTA) in children with anisometropic myopic amblyopia before and after treatment. METHODS: This prospective observational study included 32 patients younger than 12 years old with anisomyopic amblyopia. OCTA was done before patients' treatment with optical correction with or without patching and was repeated after successful amblyopia treatment. Outcomes included superficial, deep, and choriocapillaris vessel density (VD) and superficial and deep FAZ areas. RESULTS: The study included 13 males (40.6%) and 19 females (59.4%), and the mean age was 9.52 ± 1.33 years. Fifty-three percent (53%) of patients needed only optical correction, and the remaining 47% needed additional patching therapy. After successful treatment, there was a significant improvement in amblyopic eyes in best-corrected visual acuity (p < 0.001), with higher VD values in superficial capillary plexuses (p < 0.001), deep capillary plexuses (p < 0.001), and foveal choriocapillaris (p = 0.030). In the glasses with patching subgroup, the difference between pre-treatment and post-treatment parameters revealed a significant improvement in vessel density in superficial retinal plexuses (foveal and parafoveal; p values 0.023 and < 0.001, respectively) and deep retinal plexuses (whole image, foveal, and parafoveal; p values 0.003, < 0.001, and 0.002, respectively). While amblyopic eyes treated with glasses alone had a significantly greater difference in choriocapillaris foveal VD (p value = 0.022). CONCLUSION: After effective amblyopia treatment, amblyopic eyes exhibited improved best-corrected visual acuity and better macular perfusion along the superficial, deep vascular density, and choriocapillaris foveal VD. CLINICAL TRIAL REGISTRATION: CinicalTrials.gov Identifier: NCT05223153.

The Influence of Myopia on the Foveal Avascular Zone and Density of Blood Vessels of the Macula-An OCTA Study.

Background and Objectives: Myopia is the most common refractive eye anomaly with a prevalence that is constantly increasing. High myopia is associated with numerous complications that can lead to permanent vision loss. It is believed that the basis of these complications lies in changes in the microvasculature of the retina caused by an increase in the longitudinal axis of the eye. Materials and Methods: Optical coherence tomography angiography (OCTA) was used to analyze differences in macular zone vascular and perfusion density and foveal avascular zone (FAZ) parameters in myopic subjects. The following OCTA parameters were analyzed: the vessel and perfusion density of retinal blood vessels in the superficial plexus; the area, perimeter, and index of circularity of the foveal avascular zone (FAZ); and foveal and ganglion cell complex (GCC) thickness. Results: Subjects with low myopia did not show statistically significant differences compared to the control for any of the analyzed parameters. Groups with moderate and high myopia showed a significant decrease in vessel and perfusion density in the parafoveal and the entire 3 × 3 mm analyzed field. Foveal vessel and perfusion densities in the myopic groups were similar to those of the control regardless of the degree of myopia. The area and perimeter of the FAZ, as well as foveal and mean GCC thickness, did not differ significantly no matter the degree of myopia, while the index of circularity was lower in highly myopic subjects. The minimal thickness of the GCC was also lower in the high myopia group. Conclusions: High and moderate myopia led to a loss of blood vessels in the macular region. Perfusion and vascular densities were preserved in the foveal region and were not affected by different degrees of myopia. The FAZ was not significantly larger in myopic subjects, but its circularity was lower in subjects with high myopia.

Quantitative Parameters Relevant for Diabetic Macular Edema Evaluation by Optical Coherence Tomography Angiography.

Diabetic macular edema (DME) is one of the main ocular complications of diabetes mellitus (DM) that can lead to important vision loss in diabetic patients. In clinical practice, there are cases of DME with unsatisfying treatment responses, despite adequate therapeutic management. Diabetic macular ischemia (DMI) is one of the causes suggested to be associated with the persistence of fluid accumulation. Optical coherence tomography angiography (OCTA) is a non-invasive imaging modality, able to give in-depth information about retinal vascularization in a 3-dimensional manner. The OCTA devices currently available can provide various OCTA metrics that quantitatively assess the retinal microvasculature. In this paper, we reviewed the results of multiple studies that investigated the changes in OCTA metrics in the setting of DME and their possible contribution to the diagnosis, therapeutic management, follow-up and prognosis of patients with DME. We analyzed and compared relevant studies that investigated OCTA parameters related to changes in macular perfusion in the setting of DME and we evaluated the correlations between DME and several quantitative parameters, such as vessel density (VD), perfusion density (PD), foveal avascular zone (FAZ)-related parameters, as well as complexity indices of retinal vasculature. The results of our research showed that OCTA metrics, evaluated especially at the level of the deep vascular plexus (DVP), are useful instruments that can contribute to the assessment of patients with DME.

Morphological Changes in the Foveal Avascular Zone after Panretinal Photocoagulation for Diabetic Retinopathy Using OCTA: A Study Focusing on Macular Ischemia.

Background and objectives: This study aimed to analyze the morphological changes in the foveal avascular zone (FAZ) after panretinal photocoagulation (PRP) in patients with diabetic retinopathy, with a particular focus on the presence or absence of comorbid diabetic macular ischemia (DMI), using optical coherence tomography angiography (OCTA). Materials and Methods: Treatment-naïve 25 eyes of 16 patients who received PRP were examined in this retrospective case series. FAZ area, perimeter, and circularity were calculated on a 3 × 3-mm en-face OCTA image before PRP (baseline) and 1 and 3 months after PRP. The patients were divided into two groups according to coexisting DMI, and each group was statistically analyzed. Results: In patients with DMI (9 eyes), FAZ area significantly decreased from the baseline to 3 months after PRP (0.86 ± 0.56 to 0.61 ± 0.31 mm2, p = 0.018), whereas FAZ perimeter and circularity remained unchanged following treatment (p = 0.569 and 0.971, respectively). In patients without DMI (16 eyes), FAZ parameters did not show statistically significant changes across the 3-month follow-up period. Conclusion: PRP significantly reduces FAZ area in patients with DMI.

Macular microvascular changes in children with transfusion-dependent beta-thalassemia.

BACKGROUND: To investigate the effect of iron overload on macular perfusion among transfusion-dependent thalassemia (TDT) patients using optical coherence tomography angiography (OCTA) METHODS: The study is a prospective observational case-control study. It included 27 eyes from 27 children with transfusion-dependent ß-thalassemia and 25 eyes from 25 age-matched controls. All participants were evaluated clinically and with OCTA Avanti RTVue-XR system (Optovue) to assess macular microvascular changes, by measuring vessels density (VDs) and foveal avascular zone (FAZ) area, at both superficial and deep retinal plexuses and at choriocapillaris level. RESULTS: Foveal and parafoveal zones were significantly thinner among thalassemia patients, with significantly larger FAZ area at the level of both superficial and deep retinal plexuses when compared with control group. The thalassemia group showed significant lower values compared with the controls regarding whole-image, foveal, and parafoveal deep VD. There were significant negative correlations between serum ferritin and deep (whole image and parafoveal) VD (r = - 0.429, P = 0.026, and r = - 0.452, P = 0.018, respectively). Choriocapillaris VDs (whole image and foveal) showed significant negative correlations with serum ferritin levels (r = - 0.390, P = 0.044 and r = - 0.401, P = 0.038, respectively) CONCLUSIONS: Macular microvascular changes were detected by OCTA examination in patients with TDT, mostly due to iron overload effect, as we selected patients on iron-chelating agent with the least harmful effect on the retina. The most affected layer is the DCP. Changes at the deep layer could be used as a sensitive biomarker for early macular perfusion changes in those patients. TRIAL REGISTRATION: Study registration number is UMIN000042657, date of registration: 2020/12/04 (retrospectively registered).

Evaluation of radiation maculopathy after treatment of choroidal melanoma with ruthenium-106 using optical coherence tomography angiography.

BACKGROUND: To assess the impact of brachytherapy on macular microvasculature utilizing optical coherence tomography angiography (OCTA) in treated choroidal melanoma. METHODS: In this retrospective observational case series, we reviewed the recorded data of the patients with unilateral extramacular choroidal melanoma treated with ruthenium - 106 (106Ru) plaque radiotherapy with a follow-up period of more than 6 months. Automatically measured OCTA retinal parameters were analysed after image processing. RESULTS: Thirty-one eyes of 31 patients with the mean age of 51.1 years were recruited. Six eyes had no radiation maculopathy (RM). From 25 eyes with RM, nine eyes (36%) revealed a burnout macular microvasculature with imperceptible vascular details. Twenty-one non-irradiated fellow eyes from the enrolled patients were considered as the control group. Foveal and optic disc radiation dose had the highest value to predict the burnout pattern (ROC, AUC: 0.763, 0.727). Superficial and deep foveal avascular zone (FAZ) were larger in irradiated eyes in comparison to non-irradiated fellow eyes (1629 µm2 vs. 428 µm2, P = 0.005; 1837 µm2 vs 268 µm2, P = 0.021; respectively). Foveal and parafoveal vascular area density (VAD) and vascular skeleton density (VSD) in both superficial and deep capillary plexus (SCP and DCP) were decreased in all irradiated eyes in comparison with non-irradiated fellow eyes (P < 0.001). Compared with non-irradiated fellow eyes, irradiated eyes without RM had significantly lower VAD and VSD at foveal and parafoveal DCP (all P < 0.02). However, these differences at SCP were not statistically significant. CONCLUSION: The OCTA is a valuable tool for evaluating RM. Initial subclinical microvascular insult after 106Ru brachytherapy is more likely to occur in DCP. The deep FAZ area was identified as a more critical biomarker of BCVA than superficial FAZ in these patients.

Impacts of Camellia sinensis fermentation end-product (black tea) on retinal microvasculature: an updated OCTA analysis.

BACKGROUND: Tea, second only to water, is one of the most regularly consumed drinks in the world. Its potentially beneficial effects on general health may be enormously important. Optical coherence tomography angiography (OCTA) now allows clinicians to examine the acute retinal morphological changes caused by black tea consumption. The purpose of this study was to investigate the acute impacts of a Camellia sinensis fermentation end-product (black tea) on retinal microvasculature in healthy individuals using OCTA. RESULTS: In this study, 60 healthy people were divided into two groups: group 1 (n = 30) received black tea (2 mg/250 mL of water) and group 2 (n = 30) received only 250 mL of water. Following consumption, AngioVue Analytics software automatically analyzed the foveal, parafoveal, perifoveal macular superficial and deep vascular plexus densities, foveal avascular zone (FAZ) area, FAZ perimeter and foveal vessel density in a 300 µm wide region around the FAZ (FD-300). Male-to-female ratios were 19:11 and 15:15 in groups 1 and 2, respectively (P = 0.217). Mean age was 33.27 ± 7.92 years in group 1 and 31.00 ± 7.30 years in group 2 (P = 0.254). Changes in foveal, perifoveal and parafoveal macular vessel density between groups 1 and 2 were not statistically significant. In addition, no significant differences regarding FAZ, FAZ perimeter and FD-300 were observed. CONCLUSION: There were no acute effects of black tea on macular microcirculation in healthy individuals. The authors, however, believe that this study could serve as a model for future research on the relationship between regular tea consumption and general ocular physiology. © 2021 Society of Chemical Industry.

Evaluation of retinal vascular structure after epiretinal membrane surgery by optical coherence tomography angiography.

PURPOSE: To evaluate the retinal vascular structure before and after the epiretinal membrane (ERM) surgery by optical coherence tomography angiography (OCTA). METHODS: Twenty-two eyes with ERM (study eyes) had been evaluated by OCTA for superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density (VD) at foveal and parafoveal regions and foveal avascular zone (FAZ) before and after ERM removal surgery. Twenty-two fellow eyes were selected as control group. RESULTS: Preoperative VD of SCP and DCP were significantly lower in ERM eyes than in controls in both foveal and parafoveal areas (p < 0.05, for all). The difference regressed in SCP (fovea: 18.04 ± 3.1 vs 19.98 ± 18 p = 0.002 and parafovea: 47.33 ± 3.54 vs 49.71 ± 28 p = 0.001), but persisted in DCP (fovea: 17.25 ± 3.52 vs 17.57 ± 4.01 p = 0.856 and parafovea: 50.12 ± 4.35 vs 50.93 ± 3.24 p = 0.791) in study eyes, postoperatively. Superficial and deep FAZ areas were significantly smaller in study eyes than controls. Postoperatively, superficial FAZ area enlarged (0.288 ± 0.10 vs 0.307 ± 0.08 p = 0.012), whereas deep FAZ area did not (0.324 ± 0.09 vs 0.338 ± 0.07 p = 0.435). FAZ area was correlated with the best-corrected visual acuity in ERM eyes. CONCLUSION: Vascular damage in SCP and DCP was demonstrated by OCTA in eyes with ERM. ERM removal surgery mainly improves superficial changes caused by ERM. Changes in deep retinal flow may be associated with visual outcomes after ERM removal surgery.

Giant FAZ10 is required for flagellum attachment zone stabilization and furrow positioning in Trypanosoma brucei.

The flagellum and flagellum attachment zone (FAZ) are important cytoskeletal structures in trypanosomatids, being required for motility, cell division and cell morphogenesis. Trypanosomatid cytoskeletons contain abundant high molecular mass proteins (HMMPs), but many of their biological functions are still unclear. Here, we report the characterization of the giant FAZ protein, FAZ10, in Trypanosoma brucei, which, using immunoelectron microscopy, we show localizes to the intermembrane staples in the FAZ intracellular domain. Our data show that FAZ10 is a giant cytoskeletal protein essential for normal growth and morphology in both procyclic and bloodstream parasite life cycle stages, with its depletion leading to defects in cell morphogenesis, flagellum attachment, and kinetoplast and nucleus positioning. We show that the flagellum attachment defects are probably brought about by reduced tethering of the proximal domain of the paraflagellar rod to the FAZ filament. Further, FAZ10 depletion also reduces abundance of FAZ flagellum domain protein, ClpGM6. Moreover, ablation of FAZ10 impaired the timing and placement of the cleavage furrow during cytokinesis, resulting in premature or asymmetrical cell division.

Evaluation of retinal vasculature before and after treatment of children with obstructive sleep apnea-hypopnea syndrome by optical coherence tomography angiography.

PURPOSE: To evaluate the effect of adenoidectomy on the brains of children with obstructive sleep apnea-hypopnea syndrome (OSAS) through observation of the alteration of retinal perfusion by optical coherence tomography angiography (OCTA). METHODS: Sixty-two children with OSAS (124 eyes; 5.94 ± 1.64 years old; 53.2% boys) were enrolled in this study. Their retinal vascular network density indices, including vascular diameter (VD), vascular area density (VAD), vessel skeleton density (VSD), vessel perimeter index (VPI) on the macular superficial/deep capillary plexus (SCP/DCP), and the size of the foveal avascular zone (FAZ) were analyzed by OCTA before treatment and at 1 month after the adenoidectomy. RESULTS: After the adenoidectomy, the values of VD, VAD, VSD, and VPI in the SCP/DCP of the parafovea were significantly increased (p < 0.01). The FAZ was significantly diminished in the SCP (t = 4.50, p < 0.05) and increased in the DCP (t = - 4.43, p < 0.05). The peripapillary indices in the SCP/DCP were not significantly changed (p > 0.05). CONCLUSION: By improvement of hypoxia, the response of the parafoveal vessels was more sensitive than that of the peripapillary region in children with OSAS. Therefore, OCTA may be an ideal method to evaluate the changes of the retinal vascular system, which could be an effective parameter for the early evaluation of adenoidectomy on cases of pediatric OSAS.

Enlargement of the foveal avascular zone detected by optical coherence tomography angiography in diabetic children without diabetic retinopathy.

PURPOSE: Evaluation of foveal avascular zone (FAZ) in children with diabetes (DM) using OCTA. METHODS: We examined 112 diabetic children without DR aged 6-18 years and 30 age-matched controls using Topcon OCT Angiography and measured FAZ in superficial (SCP) and deep capillary plexus (DCP). The study group was divided into three subgroups depending on DM duration group 1: < 5 years (n = 40), group 2: 5-10 years (n = 42), group 3: > 10 years (n = 30). RESULTS: The mean DCP FAZ increased with DM duration from 502.2 µm2 (SD 137.8) in group 1 to 523.9 µm2 (SD 159.2) in group 2 and 539.7 µm2 (SD 189.1) in group 3. Control group differed significantly from group 1 (p = 0.0120), group 2 (p = 0.0019) and group 3 (p = 0.0011). The mean DCP to SCP FAZ surface ratio was 1.88 (SD 0.68) in the study vs 1.58 (SD 0.48) in the control group (p = 0.0232). The DCP and SCP FAZ surface difference was 217.6 µm2 (SD 100.8 µm2) in diabetics vs. 124.2 µm2 (SD 72.8 µm2) in controls (p < 0.0001). In the control group, it was significantly smaller than in group 1 (p < 0.006), group 2 (p < 0.0001) and group 3 (p < 0.0001). CONCLUSIONS: Changes can be detected in FAZ of diabetic children before DR development which can be vital for screening.

Macular vessels density in diabetic retinopathy: quantitative assessment using optical coherence tomography angiography.

PURPOSE: The aim of this study was to evaluate macular perfusion using OCTA automated software algorithms; vessel area density (VD) and non-flow tool to measure FAZ area in treatment-naïve diabetic eyes with moderate or severe NPDR and having macular edema, and correlate these parameters with LogMAR (logarithm of the minimum angle of resolution) visual acuity. Diabetic eyes without macular edema were included, to detect and define differences within the parameters between diabetic eyes with and without macular edema. METHODS: Forty-five diabetic eyes with diabetic macular edema, forty diabetic eyes without macular edema, and forty eyes of healthy controls were examined using OCTA (RTVue-XR Avanti; Optovue, Inc, Fremont, CA). The macular vessel area density (VD) and foveal avascular zone (FAZ) area were assessed and statistically compared between the three groups and also correlated with the foveal thickness and visual acuity. Data were entered and analyzed by SPSS 19. Quantitative data were presented as mean and standard deviation, and qualitative data presented as frequency distribution; independent samples t test, Chi square test and Pearson correlation were done. RESULTS: Mean whole image VD was 44.4 ± 3.6 in diabetic eyes with DME, 45.6 ± 4.2 in diabetics without DME, and 49 ± 3.9 in control eyes (P = 0.001). Diabetic eyes with DME had significantly lower vessels density values at the level of the deep retinal plexus (in the parafoveal, superior hemi, inferior hemi, temporal, superior, and nasal areas), when compared with diabetic eyes without DME. In diabetic eyes with DME, significant fair negative correlation was found between whole image vessels density at the level of the superficial retinal plexus and LogMAR VA (r = - 0.313, P = 0.036). Also, a significant fair positive correlation was found between FAZ area (at both the superficial and deep retinal plexus) and LogMAR visual acuity, in diabetic eyes with DME, where eyes with larger FAZ area had worse vision (P = 0.005 and P = 0.016, respectively). Diabetic eyes with DME had significantly larger FAZ area at the level of the superficial capillary plexus (mean superficial FAZ ± SD 0.55 ± 0.25) than diabetic eyes without edema (mean superficial FAZ ± SD 0.41 ± 0.12) and control subjects (mean superficial FAZ ± SD 0.35 ± 0.09). CONCLUSION: Using OCTA machine with AngioAnalytics parameters (vessel area density and non-flow area) helped in objective quantification of macular perfusion and accurately measuring the FAZ area in diabetic eyes with macular edema. Both parameters were significantly correlated with visual function in treatment-naïve diabetic eyes with edema. These OCTA biomarkers could be used to predict visual function in such eyes, to monitor response to treatment.

Microvascular Density Analysis of Patients with Inactive Systemic Lupus Erythematosus-A Two-Year Follow-Up Optical Coherence Tomography Angiography Study.

Background/Objectives: This study aims to investigate the long-term effect of inactive systemic lupus erythematosus (SLE) on the retinal microcirculation measured via optical coherence tomography angiography (OCT-A). Methods: Twenty-four eyes of 24 patients with inactive SLE under hydroxychloroquine (HCQ) therapy were included. The OCT-A data (mainly vessel density (VD) and foveal avascular zone (FAZ) data of the superficial and of the deep capillary plexus (SCP, DCP) and the choriocapillaris (CC)) were analyzed and compared between the baseline examination (t0) and 2 years later (t1). Results: At t1, VD in the whole en face SCP and in the CC was notably reduced compared to t0 (SCP: p = 0.001, CC: p = 0.013). VD in the DCP, CRT and FAZ area showed no difference at t1 compared to t0 (DCP: p = 0.128, FAZ: p = 0.332, CRT fovea: p = 0.296). Correlation analysis between the increase in cumulative doses of HCQ between t0 and t1 and the VD of the whole en face SCP did not show any correlation (Spearman r = 0.062 (95% CI -0.367; 0.477). Conclusions: SLE patients demonstrated a decrease in the retinal VD of the SCP and CC over a 2-year period. There was no correlation with the change in cumulative doses of HCQ. These results suggest an ongoing effect of the disease on the retinal and choriocapillary microcirculation.

Macular Vascularity and Ganglion Cell Complex Parameters in the Young Adults with Myopia and Progressive Myopia.

Purpose: The purpose of this study is to determine the relationships between foveal avascular zone (FAZ), foveal vascular density (FD) and GCC (ganglion cell complex) parameters in a healthy myopic population using optical coherence tomography angiography (angio-OCT). Patients and Methods: Three hundred and eighty-one eyes of 381 healthy participants were included into this study and assigned to three groups according to their spherical equivalent (SE) values and an additional progressive myopia group. One randomly chosen eye from each patient was analyzed. GCC mean thickness, focal loss of volume (FLV), global loss of volume (GLV), FAZ area, FAZ perimeter, and FD parameters were obtained with the RTVue AngioOCT device. Results: FAZ area and its perimeter were strongly correlated with the belonging spherical equivalent group (p = 0.0001, p = 0.0008 accordingly), being the largest in progressive myopia subgroup (mean size 0.42mm2). Other factors that were significantly higher in myopic eyes were FLV (p = 0.0023), GLV (p = 0.0020). There were no differences in FD between groups. In the myopic and progressive myopia groups, there was a significant relationship between FAZ area and FLV, GLV, and GCC thickness. We found that in myopic eyes with AXL exceeding 26.6 mm, FAZ becomes negatively correlated to mean GCC thickness. Conclusion: In myopia, compared to non-myopic groups, there is a greater loss of neural tissue represented by a thinner GCC layer, greater FLV and GLV parameters, and worse blood supply represented by a larger FAZ area. Eye axial length of 26.6 mm is a breaking point, where the negative FAZ area to GCC thickness relationship curve is getting significantly steeper.

Microvascular involvement in migraine: an optical coherence tomography angiography study.

OBJECTIVE: The aim of this study was to evaluate the microvasculature of the macula and the optic nerve in patients affected by migraine with aura (MA) and without aura (MO) by optical coherence tomography angiography (OCTA), comparing the findings with healthy controls (HC). METHODS: We collected data from ocular and orthotic examinations, including eye motility, intraocular pressure measurement, best-corrected visual acuity (BCVA) measurement, objective refraction measurement, fundus examination, macular and optic disk OCTA examination. All subjects were imaged with solix fullrange OCT. The following OCTA parameters were recorded: macular vessel density (VD), inside disc VD, peripapillary VD, disc whole image VD, fovea choriocapillaris VD, fovea VD, parafovea VD, peripapillary thickness, fovea thickness, parafovea thickness, macular full retinal thickness, and foveal avascular zone (FAZ) parameters. Clinical and demographical data about migraine patients were collected by a neurologist. RESULTS: We included 56 eyes from 28 patients with a diagnosis of MO, 32 eyes from 16 patients with a diagnosis of MA, and 32 eyes from 16 HC subjects. The FAZ area was 0.230 ± 0.099 mm2 in the MO group, 0.248 ± 0.091 mm2 in the MA group and 0.184 ± 0.061 mm2 in the control group. The FAZ area was significantly larger in the MA group than in the HC group (p = 0.007). The foveal choriocapillaris VD was significantly lower in MA patients (63.6 ± 2.49%) when compared with MO patients (65.27 ± 3.29%) (p = 0.02). CONCLUSION: An impairment of retinal microcirculation can be detected in patients with MA, as demonstrated by the enlargement of FAZ. Moreover, the study of choroid circulation may reveal microvascular damage in patients with migraine with aura. OCTA is a useful non-invasive screening tool for the detection of microcirculatory disturbance in patients with migraine.

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.

Novel optical coherence tomography angiography biomarkers in the diagnosis and assessment of diabetic macular edema and diabetic macular ischemia in patients with non-proliferative diabetic retinopathy.

Purpose: The present study aims to determine the macular and choroidal optical coherence tomography angiography (OCTA) biomarkers in the assessment and monitoring of diabetic macular edema (DME) and diabetic macular ischemia (DMI) in patients with non-proliferative diabetic retinopathy (NPDR). Methods: In this cohort study, a total of 176 eyes of 110 patients with NPDR were investigated at our institute over a period of 10 months. Eyes were divided into four groups based on the severity of NPDR. Each eye was subjected to OCTA (Topcon 3D OCT-1 Maestro2) macula 6 × 6 mm2 en face. It features IMAGEnet 6 software for dynamic viewing of OCTA and imaging data. Four OCTA biomarkers for the macula were identified: foveal avascular zone area (FAZ area), foveal avascular zone contour irregularity (FAZ-CI), capillary dropout areas (CDA), and perifoveal intercapillary areas (PICA). The choroidal OCTA biomarker was the number of choroidal circulation flow voids (CCFV). For all analyses, P < 0.05 was considered statistically significant. Results: Increase in FAZ area and number of CDA were statistically significant (p < 0.0001) with an increase in central foveal thickness, suggesting a correlation of ischemic changes with an increase in DME. FAZ-CI, enlarged PICA, and CCFV were significantly associated with more severe NPDR patients. Conclusion: A correlation between DME and DMI in a patient of NPDR and its progression can be evaluated in a single visit. A unique feature of our study is it revealed novel diagnostic biomarkers of OCTA for DMI and DME.

Quantitative analysis of retinal microvascular structure and correlation with ocular parameters: A normative database of pediatric OCT angiography.

PURPOSE: To analyze the vascular structure of the healthy pediatric population using optical coherence tomography angiography (OCTA), and to investigate its relationship with ocular parameters. MATERIALS AND METHOD: This cross-sectional, prospective study included 142 eyes of 71 healthy subjects aged 8-18 years. All patients underwent a complete ocular assessment, biometric evaluation and OCTA analysis. Anterior chamber depth, axial length, corneal thickness values were also reported and their relationship with OCTA measurements was evaluated. RESULTS: There was no statistical difference between girls and boys in terms of demographic characteristics (p>0.05). Neither vascular density in the deep and superficial capillary plexus nor FAZ area was significantly related to the ocular parameters or age of any patient in the study. CONCLUSIONS: Despite the relatively small number of participants, this study may represent normative data for the Turkish pediatric population. It was also shown that vascular density and FAZ area in childhood are not affected by age, axis length, anterior chamber depth, cornea and foveal thickness.