Deep Foveal Avascular Zone Research Articles

Optical coherence tomography angiography reveals retinal microvascular changes in patients with multiple sclerosis without optic neuritis

AbstractPurpose: Retinal imaging has attracted much interest as a non‐invasive low‐budget biomarker for neurological diseases such as multiple sclerosis (MS). Optical coherence tomography angiography (OCTA) is a functional extension of OCT and allows for the non‐invasive visualization of the retinal and choroidal microvasculature. We investigated retinal microvasculature changes in patients with relapsing–remitting MS (RRMS) without history of optic neuritis (ON) and compared them to a healthy control group.Methods: The study was performed in a prospective, case–control design, including 58 participants (n = 100 eyes) with RRMS without ON and 78 age‐ and sex‐matched control participants (n = 136 eyes). OCTA images of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris (CC) were obtained using a commercial OCTA system (Zeiss Cirrus HD‐5000 Spectral‐Domain OCT with AngioPlex OCTA, Carl Zeiss Meditec, Dublin, CA). Perfusion density (PD) and foveal avascular zone (FAZ) features (area and circularity) in both the SCP and DCP, as well as flow deficit in the CC were used as outcome variables.Results: MS patients showed significantly increased PD in SCP (p = 0.003) and decreased PD in DCP (p < 0.001) as compared to controls when data were corrected for confounders. A significant difference was also noted when large vessels (LV) in the SCP were removed from the PD calculation (p = 0.004). Deep FAZ was significantly larger (p = 0.005) and less circular (p < 0.001) in the eyes of MS patients compared to healthy controls. Neither LV, PD or FAZ features in the SCP, nor flow deficits in the CC showed any statistically significant differences between the MS patients and the controls (p > 0.186).Conclusions: Our study shows that MS patients have microvascular changes in the macular parafoveal retina even without ON. They show increased PD in SCP and decreased PD in DCP. To which degree retinal biomarkers in MS are associated with the progression of MS remains to be studied.

Normative Vascular Features on OCT Angiography in Healthy Nepalese Eyes.

To establish normative data on morphological characteristics and quantitative parameters of Foveal Avascular Zone (FAZ) as well as their systemic and ocular associations using OCT angiography (OCT-A) in healthy Nepalese subjects. A prospective, cross-sectional, population-based study recruiting 210 healthy samples (420 eyes) aged 10 to 70 years was conducted. All the samples underwent detailed comprehensive eye examination followed by Optical Coherence Tomography Angiography (OCTA) and Enhanced Depth Imaging performed in each eye using Spectral Domain Optical Coherence Tomography. Foveal avascular zone area and vessel density in superficial and deep retinal plexus and Sub foveal Choroidal Thickness (SFCT) were evaluated. Ocular and systemic associations of these parameters were also studied in a multivariate analysis utilizing linear regression. The mean superficial and deep FAZ area was 459.96 ± 124.75 μm (95% confidence interval [CI], 443.08-476.83) and 589.0 ± 141.39 μm (95% CL, 570.77-609.02), respectively. The vessel density in superficial capillary plexus was 54.03 ± 9.34% (95% CL, 53.98-54.11) while the vessel density in deep capillary plexus was 25.91 ± 38% (95% CL, 25.85-25.96). The mean SFCT in this study was 308.89 ± 68.87μm (95% CL, 299.64-318.14 μm). There was no statistically significant inter-eye difference in the FAZ parameters. Myopic eyes had smaller FAZ, lesser vessel density and thinner SFCT. Association was observed between superficial FAZ area and systolic blood pressure, and deep FAZ area and diastolic blood pressure. This study reports the normative data on FAZ parameters in healthy Nepalese subjects which can serve as references for interpreting these parameters in different retinal-choroidal diseases.

Analysis of Retinal Microvasculature Features in Amblyopic Eyes: A Meta-Analysis

Background: Amblyopia is a common cause of visual disorder with several changes in retinal structure and vessel. To date, alterations in retinal microvasculature features in amblyopia have yielded inconsistent results. Objectives: This meta-analysis aimed to evaluate retinal vessel density (VD) in amblyopic patients using optical coherence tomography angiography (OCTA). Methods: PubMed, Web of Science, Embase, and Cochrane Library databases were systematically searched for published articles comparing retinal microvasculature characteristics in patients with amblyopia and controls. Continuous variable outcomes were assessed using the mean difference (MD) with a 95% confidence interval. Review Manager Version 5.30 was used for the analysis. Results: Thirteen qualified articles were pooled in this meta-analysis. Compared with controls, the foveal whole en face VD of superficial capillary plexus (SCP) and deep capillary plexus (DCP) of patients as measured by 3 × 3-mm scans were significantly lower in amblyopia eyes (MD: −1.37, p = 0.0003; MD: 1.70, p < 0.00001, respectively). Similarly, in the 6 × 6-mm scans, foveal whole en face VD of the SCP and DCP were remarkably lower in amblyopia eyes than in controls (MD: −2.24, p = 0.03; MD: −5.08, p = 0.04, respectively). The parafoveal VD of SCP in 3 × 3-mm scans (MD: −1.96, p < 0.00001) was also lower in amblyopic patients than in controls. Similarly, in 6 × 6-mm scans, amblyopia eyes showed a significant decrease and a trending decrease in the parafoveal VD of the SCP (MD: −3.85, p = 0.007) and DCP (MD: −3.03, p = 0.10), respectively. For whole radial peripapillary capillary (RPC), VD was significantly reduced in amblyopic patients compared to controls (MD = −0.83, p < 0.00001). In addition, the deep foveal avascular zone (FAZ) was larger in amblyopic eyes than in the controls (MD = 0.55, p = 0.007). Conclusions: Our data suggest that whole foveal and parafoveal VD and RPC whole VD were reduced in patients with amblyopia. Moreover, our results reveal that the FAZ is larger in amblyopic patients. Consequently, OCTA may have the potential for diagnosing and monitoring patients with amblyopia.

Comparison of retinochoroidal microvascular circulation in menstrual and postmenopausal periods using swept-source optical coherence tomography angiography.

We aimed to examine the possible effects of the postmenopausal period on retinal and choroidal microvascular circulation using swept-source optical coherence tomography angiography (SS-OCTA). This cross-sectional study included 45 eyes of 45 subjects in menstrual group and 40 eyes of 40 subjects in postmenopausal group. SS-OCTA was used for the assessment of vessel density (VD), foveal avascular zone (FAZ), choroidal thickness (CT), choriocapillaris VD, central macular thickness (CMT), nerve fiber layer thickness (RNFL), and ganglion cell layer (GCL) measurements. The VDs of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) measurements were similar in both group. FAZ area was wider in postmenopausal group (0.305 mm2 (range, 0.212-0.498 mm2)) compared to menstrual group (0.271 mm2 (range, 0.131-0.464 mm2)) (p = 0.013). Choriocapillaris VD was significantly lower in postmenopausal group (p = 0.049). CT was thicker in the postmenopausal group, but with no statistically significant difference (p = 0.066). Central macular thickness, RNFL, and GCL were similar in both groups. This is the first study in the literature to evaluate the retinochoroidal microcirculation in the menstrual and postmenopausal periods with SS-OCTA. We observed an increase in both superficial and deep FAZ area and a decrease in choroidal blood flow in the postmenopausal period. We think that this enlargement in the FAZ area may be related to the decreased amount of estrogen.

Microvascular changes in the macular and parafoveal areas of multiple sclerosis patients without optic neuritis

Retinal imaging has been proposed as a biomarker for neurological diseases such as multiple sclerosis (MS). Recently, a technique for non-invasive assessment of the retinal microvasculature called optical coherence tomography angiography (OCTA) was introduced. We investigated retinal microvasculature alterations in participants with relapsing–remitting MS (RRMS) without history of optic neuritis (ON) and compared them to a healthy control group. The study was performed in a prospective, case–control design, including 58 participants (n = 100 eyes) with RRMS without ON and 78 age- and sex-matched control participants (n = 136 eyes). OCTA images of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris (CC) were obtained using a commercial OCTA system (Zeiss Cirrus HD-5000 Spectral-Domain OCT with AngioPlex OCTA, Carl Zeiss Meditec, Dublin, CA). The outcome variables were perfusion density (PD) and foveal avascular zone (FAZ) features (area and circularity) in both the SCP and DCP, and flow deficit in the CC. MS group had on average higher intraocular pressure (IOP) than controls (P < 0.001). After adjusting for confounders, MS participants showed significantly increased PD in SCP (P = 0.003) and decreased PD in DCP (P < 0.001) as compared to controls. A significant difference was still noted when large vessels (LV) in the SCP were removed from the PD calculation (P = 0.004). Deep FAZ was significantly larger (P = 0.005) and less circular (P < 0.001) in the eyes of MS participants compared to the control ones. Neither LV, PD or FAZ features in the SCP, nor flow deficits in the CC showed any statistically significant differences between the MS group and control group (P > 0.186). Our study indicates that there are microvascular changes in the macular parafoveal retina of RRMS patients without ON, showing increased PD in SCP and decreased PD in DCP. Further studies with a larger cohort of MS patients and MRI correlations are necessary to validate retinal microvascular changes as imaging biomarkers for diagnosis and screening of MS.

Evaluation of macular vascular density and foveal avascular zone changes by optical coherence tomography angiography (OCT-A) after intravitreal dexamethasone implant in diabetic macular edema resistant to Anti-VEGF treatment.

Analysis of foveal avascular zone (FAZ) width and vascular density (VD) changes before and after intravitreal dexamethasone implant (IDI) treatment in diabetic macular edema (DME) patients resistant to anti-VEGF treatment. In this retrospective study, patients who were regularly treated with at least 5 doses of intravitreal Anti-VEGF (bevacizumab, ranibizumab or aflibercept) for DME and whose DME continued were considered resistant to Anti-VEGF and were treated with IDI for the first time. Thirty-four eyes of 34 patients were included in the study. FAZ and VD values of optical coherence tomography angiography (OCT-A) scans at 0, 1 and 3months were examined. In OCT-A measurements, the pre-IDI superficial plexus FAZ (SFAZ) area (0.350 ± 0.120 mm2) was decreased at 1 (0.292 ± 0.132 mm2, p < 0.001) and at 3months (0.311 ± 0.153 mm2, p = 0.017). Pre-IDI deep plexus FAZ (DFAZ) area (0.651 ± 0.313 mm2) was decreased at 1-month post-IDI (0.481 ± 0.247 mm2, p < 0.001) while no significant change was observed at 3months (0.575 ± 0.259 mm2, p = 0.197). There was no significant change in the mean post-IDI total VD rate in both superficial (pre 39.2% ± 2.4; 1st month 39.2% ± 2.6%; 3rd month 39.5% ± 3.4%) and deep retinal plexus (pre 43.3% ± 2.6%; 1st month 43.5 ± 2.8%; 3rd month 43.6% ± 4.6%) (p = 0.408 and p = 0.607, respectively). The study showed that IDI caused a significant decrease in the FAZ area without any change in VD in patients with DME resistant to the anti-VEGF agents. IDI might be related to a decrease in the macular ischemia secondary to diabetic retinopathy.

Optical coherence tomography angiography metrics in different stages of diabetic macular edema

BackgroundTo investigate the optical coherence tomography angiography (OCTA) characteristics of diabetic macular edema (DME) at different stages.MethodsThis study was a cross-sectional study. Patients diagnosed with DME were recruited. DME was classified into early, advanced, and severe DME. The vessel density (VD) in the superficial vascular plexus (SVP), deep vascular plexus (DVP) and foveal avascular zone (FAZ) parameters, including FAZ area, FAZ perimeter, acircularity index and foveal VD in a 300-μm-wide region around the FAZ (FD-300), were calculated by the AngioVue software. A multivariate generalized estimating equation was used to evaluate the associations between visual acuity and OCTA metrics.ResultsNinety-two eyes from 74 patients with DME were included in this study. Compared to early (P = 0.006) and advanced DME (P = 0.003), the acircularity index was higher in severe DME. Both whole and parafoveal VD in the DVP decreased in eyes with severe DME compared to early DME (P = 0.018, P = 0.005, respectively) and advanced DME (P = 0.035, P = 0.012, respectively). In the multivariate generalized estimating equation, DME severity, FAZ area and foveal thickness were positively associated with worse visual acuity (P = 0.001, P = 0.007 and P = 0.001, respectively).ConclusionCompared to early and advanced DME, severe DME showed increased irregularity in the FAZ and more extensive vessel damage in the DVP. Greater severity level of DME, larger FAZ area, and increased foveal thickness could be risk factors for poor visual acuity.Trial registration The protocol was published in the Chinese Clinical Trial Registry (ChiCTR2000033082).

Structural, Microvascular, and Functional Findings Associated with Fovea Plana.

To analyse structural (OCT), microvascular (OCTA), and functional changes (BCVA, mfERG) associated with fovea plana and to compare it to healthy controls. A retrospective observational study was performed on 13 patients (26 eyes; aged 34.46 y ± 20.26) with a clinical picture of fovea plana and 15 controls (30 eyes; aged: 41.47 y ± 14.03). In fovea plana, BCVA ranged from 0.25 to 1.0, with a spherical error of - 5.5 to + 18.0 dpt. Posterior segment changes included elevated papillomacular retinal fold, uveal effusion syndrome, crowded optic discs, and hypopigmented fundus. OCTA imaging of the superficial (FAZ-S), intermediate (FAZ-I), and deep foveal avascular zone (FAZ-D) confirmed absence of foveal avascular zone (FAZ-S in 13 eyes, FAZ-I in 21eyes, and FAZ-D in 10 eyes). Fovea plana patients had a significantly smaller FAZ-S, FAZ-I, and FAZ-D than controls (p < 0.001). Within the fovea plana group, a smaller FAZ-S correlated with reduced BCVA (p = 0.004) and with reduced mfERGs in zones 1 and 2 (p = 0.001 and p = 0.017). Also, a smaller FAZ-D showed positive correlations with the mfERG, with statistically significant values in zones 1 and 2 (p = 0.003 and p = 0.017). In conclusion, our results confirm an altered structural, microvascular, and functional pattern in patients with a clinical picture of fovea plana. As documented by the functional microvascular interactions in our study, the developmental arrest in foveation reflects the functional maturation by means of visual acuity and central retinal function.

Retinal Microvascular Changes in Patients with Multiple Myeloma: A Study Based on Optical Coherence Tomography Angiography

Purpose: Ocular microvascular networks and variables were analyzed using optical coherence tomography angiography (OCTA) in patients with multiple myeloma (MM) who had no pathological findings in their routine ophthalmologic examinations. Methods: The study included 31 patients with a diagnosis of MM and 30 healthy controls. The ophthalmologic examination findings and OCTA measurements of the participants were prospectively analyzed. We evaluated the superficial capillary plexus (SCP) vessel density (VD) and deep capillary plexus (DCP) VD in macular region, radial peripapillary capillary (RPC) VD, optic nerve head (ONH) VD and the foveal avascular zone (FAZ) area. Results: The samples were gender-balanced, and there were no significant differences in age or gender between the MM and control groups. From the OCTA, all the ONH-VD measurements, except for the peripapillary and superotemporal parameters, were found to be significantly lower in MM patients than in the control group; the same was found for the whole image, inferonasal, superonasal, and superotemporal RPC-VD values; for all the SCP-VD values, except for the inferior hemi and temporal; and for all the DCP-VD values. It was also observed that the deep FAZ area was wider in the MM group than in the control group. Conclusions: We detected decreased VD in deep and superficial macular retinal areas, papillary, peripapillary regions, suggesting decreased blood flow and possible ischemia in MM patients. Therefore, obtaining information on ischemia by using a noninvasive and easily measurable method such as OCTA, may be beneficial in terms of follow-up and treatment but this needs to be supported by further, larger studies.

Evaluation of the effect of obstructive sleep apnea syndrome on retinal microvascularity by optical coherence tomography angiography

PurposeUsing optical coherence tomography angiography (OCTA), we sought to determine whether there are retinal microvascular changes in patients with obstructive sleep apnea syndrome (OSAS). MethodThe study included 56 patients diagnosed with OSAS by polysomnography [21 patients with mild OSAS (group 1), 14 with moderate OSAS (group 2) and 21 with severe OSAS (group 3)], and 26 healthy individuals as a control group (group 4). The vascular densities of the superficial capillary plexus and deep capillary plexus of the retinal segmentations, together with the foveal avascular zone (FAZ) width, were measured for all participants, using OCTA. ResultCompared with the control group, vascular densitiy in whole image of superficial capillary plexus were found to be significantly lower in group 2. In addition, vascular densitiy in fovea region of superficial capillary plexus was significantly lower in group 1 than the control group. In deep capillary plexus, vascular densitiy of whole image, superior hemi and nasal regions were found to be significantly lower in group 2 and group 3 compared with the control group. Parafoveal region in group 3 had significantly lower vascular densities than the controls. A significantly larger FAZ was also found in group 1 and group 3 in the deep capillary plexus, compared with the controls. ConclusionWe detected smaller vascular densities in both the superficial capillary plexus and deep capillary plexus and a larger deep capillary plexus FAZ in OSAS patients. Therefore, OCTA may be useful as a non-invasive method to understand the systemic effects of OSAS.

FAZSeg: A New Software for Quantification of the Foveal Avascular Zone.

IntroductionVarious ocular diseases and high myopia influence the anatomical reference point Foveal Avascular Zone (FAZ) dimensions. Therefore, it is important to segment and quantify the FAZs dimensions accurately. To the best of our knowledge, there is no automated tool or algorithms available to segment the FAZ’s deep retinal layer. The paper describes a new open-access software with a Graphical User Interface (GUI) and compares the results with the ground truth (manual segmentation).MethodsNinety-three healthy normal subjects included 30 emmetropia and 63 myopic subjects without any sight-threatening retinal conditions, were included in the study. The 6mm x 6mm using the Angioplex protocol (Cirrus 5000 Carl Zeiss Meditec Inc., Dublin, CA) was used, and all the images were aligned with the centre of the fovea. Each FAZ image corresponding to dimensions 420×420 pixels were used in this study. These FAZ image dimensions for the superficial and deep layers were quantified using the New Automated Software Method (NAM). The NAM-based FAZ dimensions were validated with the ground truth.ResultsThe age distribution for all 93 subjects was 28.02 ± 10.79 (range, 10.0–66.0) years. For normal subjects mean ± SD age distribution was 32.13 ± 16.27 years. Similarly, the myopia age distribution was 26.06 ± 6.06 years. The NAM had an accuracy of 91.40%. Moreover, the NAM on superficial layer FAZ gave a Dice Similarity Coefficient (DSC) score of 0.94 and Structural Similarity Index Metric (SSIM) of 0.97, while the NAM on deep layer FAZ gave a DSC score of 0.96 and SSIM of 0.98.ConclusionA clinician-based GUI software was designed and tested on the FAZ images from deep and superficial layers. The NAM outperformed the device’s inbuilt algorithm when measuring the superficial layer. This open-source software package is in the public domain and can be downloaded online.

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

BackgroundTo assess the impact of brachytherapy on macular microvasculature utilizing optical coherence tomography angiography (OCTA) in treated choroidal melanoma.MethodsIn 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.ResultsThirty-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.ConclusionThe 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.

Optical coherence tomography angiography in healthy children: A comparison of macular structure.

The purpose of the present study was to investigate the perfusion density (PD) of macular superficial (SCP) and deep capillary plexus (DCP), the size of foveal avascular zone (FAZ) and central macular thickness (CMT) in healthy children using optical coherence tomography angiography (OCT-A). About 206 eyes of 111 children were analyzed. The correlation of gestational age (GA), birth weight (BW), age, sex, refractive errors, and visual acuity (VA) with OCT-A parameters were investigated. The mean PD of the fovea and the mean FAZ area of SCP were 17.1% (DS: 4.26) and 234.47 (DS: 106.39) µm2. The mean PD of the fovea and the mean FAZ area of DCP were 13.5% (DS: 5.23) and 298.32 (DS: 112.37) µm2. Superficial and deep FAZ areas were not correlated with sex, age, BW, refractive errors, or VA. FAZ area of SCP was correlated with foveal PD (r = -0.76) and with CMT (r = -0.68). FAZ area of DCP was correlated with foveal's PD (r = -0.61). There was no correlation between CMT and refractive errors. OCT-A may provide a non-invasive and reliable approach to evaluate macular perfusion in children. As the FAZ area, PD, and CMT change during the growth period, we performed established a reference range for different ages.

Acircularity and circularity indexes of the foveal avascular zone in high myopia

This study explored the association between foveal avascular zone (FAZ) parameters and high myopia using optical coherence tomography angiography. We divided 106 eyes of 106 patients into quartiles based on the axial length. The upper quartile was then defined as the high myopia group (n = 27), while the lower quartile was the non-high myopia group (n = 26). The areas and minor axis lengths of superficial and deep FAZ, the perimeters and major axis lengths of deep FAZ were significantly larger in eyes with high myopia than in eyes with non-high myopia (P < 0.05). Inversely, the subfoveal choroidal thickness was significantly thinner in eyes with high myopia than in those with non-high myopia. Linear regression analyses showed that no significant correlation was observed between FAZ areas and acircularity and circularity indexes of FAZ in non-high myopia group. Conversely, FAZ areas strongly correlated with acircularity and circularity indexes of FAZ in high myopia group. We found that an increase in the FAZ area in highly myopic eyes was accompanied by a significant variation in FAZ acircularity and circularity indexes. Further research should address whether these findings are associated with future disease development in highly myopic eyes.

Macular density alterations in myopic choroidal neovascularization and the effect of anti-VEGF on it.

To analyse macular microvascular alterations in myopic choroidal neovascularization (mCNV) and the efficiency of anti-vascular endothelial growth factor (anti-VEGF) therapy for mCNV by optical coherence tomography angiography (OCTA). A total of 123 patients were included in this retrospective study, divided into mCNV group, high myopia (HM) group, and normal group at the Affiliated Eye Hospital of Wenzhou Medical University from January 2017 to January 2019. Superficial vessel density, deep capillary density, foveal avascular zone (FAZ) area, A-circularity index (AI) and vessel density around the 300 µm width of the FAZ region density (FD) and the area of choroidal neovascularization (CNV) lesion (only for mCNV group) were measured on 3×3 mm2 OCTA images. FAZ area was corrected for axial length. Central macular thickness (CMT) was measured on OCT in mCNV group. Compared the parameters on OCTA of 3 groups and pre-anti-VEGF and post-anti-VEGF at 1, 2, 3, and 6mo follow-up in mCNV group. There were significant differences among 3 groups in superficial vessel density, deep capillary density and FD (P<0.05). FAZ area in HM group was smaller than normal group (P<0.05), but there was no significant difference between mCNV group and the other two group. AI increased in mCNV group (P<0.05). The mean CMT, area and flow area of CNV lesion decreased after treatment (P<0.05), while vessel density and FAZ didn't change. The mean CMT, area and flow area of CNV lesion statistically decreased after anti-VEGF treatment in mCNV group (P<0.05), while superficial vessel density, deep capillary density and FAZ area, AI and FD didn't change. The mean reduction ratio of lesions was 50.32% (7.07% to 100%). Lesion regression 100% was observed in 2 cases (4.88%). There was a negative correlation between the CNV lesion area and reduction ratio (r=-0.380, P=0.042) and the flow lesion area and reduction ratio (r=-0.402, P=0.030). Macular vessel density decreases, FAZ turns smaller and more irregular in mCNV eyes. Anti-VEGF therapy is efficient for mCNV without affecting vessel density and FAZ, but it is unable to completely eliminate CNV lesions in most cases. The bigger mCNV lesions have lower reduction ratio.

Evaluation of retinal and optic nerve vasculature by optic coherence tomography angiography in Migraine with Aura

This study aimed to evaluate the retina by optic coherence tomography angiography (OCTA) in patients with migraine with aura (MA) in comparison with healthy controls. A total of 60 patients with MA and 56 control subjects who applied to the Ophthalmology Clinic of Dicle University between January 2020 and February 2020 were included in this study. In all patients, the vascular density (VD) of the radial peripapillary capillaries (RPCs) and optic nerve head (ONH), the VD of deep and superficial macular vascular networks, and foveal avascular zone (FAZ) were measured. Patients with MA showed reduced VD measurements of the nasal and inferotemporal ONH, inferonasal RPCs, and deep macular plexus. No statistically significant difference was observed in the superficial macular VD values between the study groups. The majority of patients with MA showed hypertrophy in the deep FAZ. There was a decrease in VD measurements in the deep macular capillary plexus, ONH, and peripapillary capillaries and hypertrophy in the deep FAZ in patients with MA. According to these results, patients with MA may have an increased risk of developing ocular and systemic vascular complications. Therefore, OCTA can be used to evaluate systemic and ocular hypoperfusion in patients with MA.

Evaluation of parafoveal vascular density using optical coherence tomography angiography in patients with central serous chorioretinopathy.

Using optical coherence tomography angiography (OCTA), we sought to evaluate parafoveal vascular density (VD) in patients with central serous chorioretinopathy (CSCR). Our study included 43 patients with a diagnosis of CSCR and 40 healthy controls. Ophthalmologic examination findings and OCTA measurements of the participants were retrospectively analysed. Of the 43 patients with CSCR, 31 were males (72%) and 12 were females (28%); the control group was 30 males (75%) and 10 females (25%) (p = 0.657). There were significant differences between affected eyes, unaffected eyes and healthy control eyes for all parameters in the superficial capillary plexus (SCP) VD and deep capillary plexus (DCP) VD (p < 0.05 for all values). It was also determined that the affected eyes had lower SCP-VD and DCP-VD than the unaffected eyes and that the unaffected eyes had lower SCP-VD and DCP-VD than the healthy control eyes (p < 0.05 for all values). While there were no significant differences in the deep foveal avascular zone (FAZ) area, the superficial FAZ area was larger in affected eyes than in both unaffected eyes and healthy control eyes (p < 0.05). In most areas, the SCP-VD and DCP-VD values were lower and the FAZ larger in the chronic group than in the acute group (p < 0.05). Retinal vascular changes were found in patients with both acute and chronic CSCR, and the fellow eyes of these patients were also affected. OCTA can therefore be considered an easily applicable, non-invasive screening option for evaluating the microvascular structure in these patients.

Microvascular and metabolic alterations in retinitis pigmentosa and Stargardt disease.

The aim of our study was to evaluate retinal microvascular changes recorded with optical coherence tomography angiography (OCTA) and the metabolic function measured with retinal oximetry (RO) in patients with retinitis pigmentosa (RP) and Stargardt disease (STGD). In this prospective, noninterventional study, OCTA and RO were performed on 107 eyes (56 subjects): 53 eyes diagnosed with RP without the presence of macular oedema (no-ME-RP), 26 eyes with STGD, and 28 control eyes. Main outcome measures were the mean superficial (FAZ-S; mm2 ) and deep foveal avascular zone (FAZ-D; mm2 ) measured with OCTA as well as the mean arterial (A-SO2 ; %), venular (V-SO2 ; %) oxygen saturation, their difference (A-V SO2 ; %) and the corresponding mean diameters of the peripapillary retinal arterioles (D-A; μm) and venules (D-V; μm) determined with RO. Stargardt disease (STGD) patients differed from controls and no-ME-RP by an enlarged FAZ-S and reduced A-SO2 and V-SO2 (p ≤ 0.013). No-ME-RP eyes presented with attenuated vessels (p < 0.001) and increased A-SO2 and V-SO2 (p ≤ 0.012) compared to controls and STGD. The FAZ-D showed significant interactions with A-SO2 (p = 0.003) in no-ME-RP while the FAZ-S correlated with visual acuity in no-ME-RP (p = 0.007) and STGD (p = 0.034). Retinitis pigmentosa (RP) and Stargardt disease (STGD) patients suffer from microvascular and metabolic alterations, however, showing a different pattern. A combined microvascular-metabolic model may therefore allow to more precisely characterize RP and STGD as well as presumably other inherited retinal diseases.

Evaluation of the Foveal Avascular Zone in Familial Exudative Vitreoretinopathy Using Optical Coherence Tomography Angiography.

PurposeTo evaluate the foveal avascular zone (FAZ) and retinal structure in familial exudative vitreoretinopathy (FEVR).Patients and MethodsEighteen eyes with stage 1 or 2 FEVR and 20 control eyes were evaluated. The central retinal thickness (CRT), foveal inner retinal thickness (IRT), surface retinal vessel density (SRVD), and deep retinal vessel density (DRVD) were measured using optical coherence tomography. The FAZ area was calculated using ImageJ software. The equivalent spherical value (SE) and axial length (AL) were measured.ResultsThe CRT (232.5±3.086 vs 211±12.6325 μm; p=0.003) and foveal IRT (15.83±13.95 vs 0.9±4.02 μm; p=0.002) were thicker in the FEVR group than in the control group. The surface FAZ area (0.265±0.08 vs 0.364±0.09 mm2; p=0.004) and the deep FAZ area (0.364±0.1 vs 0.484±0.11 mm2; p=0.03) were smaller in the FEVR group than in the control group. The SRVD values did not differ among the sectors, but the DRVD was higher in the FEVR group except for the inferior sector (superior, p=0.027; inferior, p=0.88; temporal, p=0.035; nasal, p=0.027). The SE and AL did not differ between the two groups. There were no correlations between the surface and deep layer FAZ area and age, CRT, SE, and AL. The surface, deep FAZ area, and foveal IRT were correlated negatively (surface, r = −0.47, p=0.033; deep layer FAZ area, r = −0.46, p=0.037).ConclusionEyes with FEVR have a smaller FAZ because the vascular structure in the inner retina remained in the fovea.

Panretinal laser photocoagulation decreases large foveal avascular zone area in non-proliferative diabetic retinopathy: A prospective OCTA study

PurposeTo analyze the macular microvascular changes after panretinal photocoagulation (PRP) in patients with non-proliferative diabetic retinopathy (NPDR) and a large foveal avascular zone area, using optical coherence tomography angiography. MethodsTwenty-four eyes of 24 patients with peripheral ischemia, superficial foveal avascular zone (FAZ) area of larger than 0.350 mm2, naive severe NPDR, and no clinically significant diabetic macular edema were included in this prospective study. The PRP was applied in 360-degree in a single session. The main outcome measures of the study were the difference in best-corrected visual acuity, central macular thickness, superficial and deep vascular plexus vessel densities, FAZ features, choroidal and outer retinal flow areas at the baseline versus at one and six months after PRP treatment. ResultsThe study group consisted of 13 men and 11 women with a mean age of 68.11 ± 6.47 years. The baseline FAZ area was higher than at one and six months after PRP (0.416 ± 0.70, 0.399 ± 0.065 and 0.407 ± 0.066 mm2; p = 0.001 and p = 0.002, respectively). At one month after PRP, deep capillary plexus vascular density in perifoveal region was statistically significantly lower than at six months after PRP and the baseline. (45.43 ± 4.27, 47.91 ± 4.26 and 49.04 ± 5.64 %; p = 0.001 and p = 0.001, respectively). ConclusionThe PRP effects retinal microvascular morphology in patients with NPDR and a large FAZ area.