Optical Coherence Tomography Angiography Scans Research Articles

Race/Ethnicity Analysis of Vascular Alterations in Optical Coherence Tomography Angiography in Diabetic Patients

ABSTRACT Purpose Racial and ethnic minorities have a higher prevalence of diabetic retinopathy (DR) and present at advanced stages of disease. In an urban hospital population, we investigated microvascular differences in optical coherence tomography angiography (OCTA) between racial/ethnic groups while adjusting for socioeconomic status (SES). Methods 3 × 3 mm2 macular OCTA scans were obtained for analysis of foveal avascular zone (FAZ) area, FAZ perimeter as well as superficial (SCP) and deep capillary plexus (DCP) vessel density (VD), vessel length density (VLD), and adjusted flow index (AFI). SES was measured using the Area Deprivation Index. Multivariable regression models were used to adjust estimates for relevant confounders. Results 217 non-diabetic and 1,809 diabetic patients were included in the study, consisting of 42.2% Hispanic, 24.9% non-Hispanic (NH) Asian, 6.8% NH Black, 9.7% NH White and 16.3% Other patients. NH White was used as the reference group. Hispanic, NH Asian, and NH Black patients had significantly greater FAZ areas and FAZ perimeters, and lower DCP VD and VLD, among both non-diabetic and diabetic patients (Benjamini-Hochberg adjusted P-values <0.05). The addition of SES scores in the models did not modify any regressions significantly. Conclusions In patients with and without diabetes, racial and ethnic minorities have significant retinal microvasculature differences when compared to NH White patients, regardless of SES. These differences are pronounced in DCP and may predispose racial/ethnic minorities to worse outcomes in DR, thus widening disparities in ophthalmic care.

Rate of Initial Optic Nerve Head Capillary Density Loss and Risk of Visual Field Progression

Rapid initial optic nerve head capillary density loss may be used to assess the risk of glaucoma visual field progression. To investigate the association between the rate of initial optic nerve head capillary density loss from optical coherence tomography angiography (OCTA) and visual field progression. This was a retrospective study of a longitudinal cohort at a glaucoma referral center. A total of 167 eyes (96 with primary open-angle glaucoma and 71 with glaucoma suspect) of 109 patients were monitored for a mean (SD) of 5.7 (1.4) years from January 2015 to December 2022. Data analysis was undertaken in April 2023. The rates of initial capillary density and average retinal nerve fiber layer loss were calculated from the first 3 optic nerve head OCTA and OCT scans, respectively, during the initial follow-up (mean [SD], 2.0 [1.0] years). Based on the median rate, eyes were categorized into fast and slow progressor groups. The association between initial capillary density change or retinal nerve fiber layer thinning and visual field progression was evaluated using linear-mixed and time-varying Cox models. A total of 167 eyes of 109 patients (mean [SD] age, 69.0 [11.1] years; 56 [51.4%] female and 53 [48.6%] male) were assessed. Eighty-three eyes were slow OCTA progressors, while 84 eyes were fast with mean capillary density loss of -0.45% per year and -1.17% per year, respectively (mean difference, -0.72%/year; 95% CI,-0.84 to -0.60; P < .001). Similarly, 83 eyes were slow OCT progressors, while 84 eyes were fast with mean retinal nerve fiber layer thinning of -0.09 μm per year and -0.60 μm per year, respectively (mean difference, -0.51 μm/year; 95% CI,-0.59 to -0.43; P < .001). The fast OCTA and OCT progressors were associated with more rapid visual field loss (mean difference, -0.18 dB/year; 95% CI,-0.30 to -0.06; P = .004 and -0.17 dB/year; 95% CI,-0.29 to -0.06; P = .002, respectively). Fast OCTA progressing eyes were more likely to have visual field progression (hazard ratio, 1.96; 95% CI, 1.04-3.69; P = .04). Seventeen of 52 eyes (32.7%; 95% CI, 32.5-32.8) with fast OCTA and OCT progression developed subsequent visual field likely progression. Rapid initial optic nerve head capillary density loss from OCTA was associated with a faster rate of visual field progression and a doubling of the risk of developing event progression in this study. These findings may support clinical use of OCTA and OCT optic nerve head measurements for risk assessment of glaucoma progression.

Foveal thickness and vascular variables in adolescents born moderate-to-late preterm.

It is well established that children born very preterm are at increased risk for ocular abnormalities including altered foveal morphology. However, little is known about how children born moderate-to-late preterm (MLP), gestational age 32 + 0-36 + 6 weeks, are affected later in life. This study investigates foveal avascular zone (FAZ) area, vascular density (VD), central foveal thickness (CFT) and ganglion cell layer thickness (GCL++) of adolescents born MLP without history of retinopathy of prematurity and compare the results with full-term controls. In a prospective population-based cohort study, 50 adolescents (26 girls; mean age 16.5 years) born MLP were examined with optical coherence tomography (OCT) and OCT angiography (OCT-A). FAZ and VD were obtained from OCT-A scans and adjusted for ocular magnification. CFT and GCL++ were obtained from the OCT scans. The results from the MLP individuals were compared with the results from 49 healthy full-term controls (29 girls; mean age 16.7 years). The results showed statistically significant differences in FAZ area (0.22 vs 0.28 mm2; p = 0.0032) and CFT (198.1 vs 187.1 μm; p = 0.0010) between the MLP group and controls. Strong correlations between FAZ area and CFT (r = -0.773, p < 0.0001) and GCL++ (r = -0.924, p < 0.0001) were found in the MLP group. There were no differences in VD. Our results show that adolescents born MLP have a smaller FAZ area and an increased CFT compared with full-term controls. These results indicate that adolescents born MLP have similar parafoveal changes as children born extreme or very preterm.

Contribution of systemic factors on macular vessel density: a sex-specific population-based study.

To evaluate the influence of systemic factors on macular vessel density in quantitative Optical Coherence Tomography Angiography (OCTA) by sex. A cross-sectional study. A total of 2018 adults were recruited in this study. Participants were excluded (n=964) due to missing data, eye-related problems, or low OCTA scan quality. Macular vessel densities were measured with OCTA using split-spectrum amplitude decorrelation angiography algorithm. Only the data from the right eyes were selected for analysis. Multivariable linear regression analysis was performed to determine the associations between macular vessel density and obesity-related systemic factors in each gender group. The right eyes of 1054 participants (59.6% women) were enrolled. Men had significantly higher obesity parameters and associated risk factors. In multivariable linear regression analysis in men, older age and type 2 diabetes mellitus were independently associated with lower superficial retinal vessel density (β = -0.37, p = 0.002; β = -1.22, p = 0.03) and deep retinal vessel density, respectively (β = -0.66, p < 0.001; β = -1.76, p = 0.02); positive association was also observed between body mass index (BMI) and superficial retinal vessel density (β = 0.56, p = 0.02). In women, only higher systolic blood pressure was independently associated with a lower deep retinal vessel density (β = -0.50, p = 0.003). This large cross-sectional study shows that older age and type 2 diabetes mellitus are associated with lower superficial and deep retinal capillary vessel density in men. This may help clinicians better understand how systemic factors influence retinal vessel density in different genders and future studies can ascertain more potential sex differences.

Quantitative evaluation of OCT angiography images in healthy and glaucomatous subjects through a novel approach: exploring inter-image variability.

This study aims to investigate inter-image intra-observer variability of macular, and optic disc (ONH) microvasculature measurements of glaucomatous and normal subjects using Swept-Source Optical Coherence Tomography Angiography (OCT-A) (OCT Topcon ImageNet 6; DRI OCT Triton, Topcon Corporation, JAPAN) - based imaging data analysis and processing with a newly made quantitative approach. A total of 20 glaucomatous and 20 healthy eyes underwent three OCT-A scanning of the ONH and macula. Macular and papillary and peripapillary vascular networks were calculated. For each eye, eighteen scans were analyzed using a novel approach: custom MATLAB 2021b scripts were employed for imaging analyses. Grayscale distribution was performed using the histcounts MATLAB function with 51 bins. For all layers, the vascular layer coefficient of variation (vl CoV) of the three measures were performed. The vl CoV difference between the two groups was analyzed by Student t-test. In glaucomatous eyes, the vl CoV ranged from 4.49% to 8.54%, while in the control group from 3.58% to 8.32%. Both groups exhibited higher CoVs when assessing the optic disc. The papillary and macular microvasculature reproducibility was comparable between groups. Utilizing Swept-Source OCT-A images our study has identified an easy and reproducible method that appears to be fast and can assist physicians in assessing macular and ONH perfusion with less inter-image variability, particularly in the 70 μm superficial area of the optic disc. The high reliability obtained suggested that this method could be useful as early clinical biomarker.

Evaluation of the effect of phacoemulsification surgery on retinal and choroidal microvasculature in diabetic patients using optical coherence tomography angiography

Aim To evaluate the effect of phacoemulsification surgery on retinal and choroidal microvasculature in diabetic patients using optical coherence tomography angiography (OCTA). Settings and design A prospective comparative case-control study was performed at the Ophthalmology Department of Ain Shams University hospital, between November 2020 and November 2022. Patients and material A total 50 eyes of 35 cataractous patients were included in this prospective study and divided into two groups: the control group (25 eyes of 19 patients) and the diabetic group (25 eyes of 16 patients with mild nonproliferative diabetic retinopathy). All patients underwent routine ophthalmic examination, OCT and OCTA scans of the macula before phacoemulsification surgery and 1 week, 1, 3, and 6 months after the surgery. Results The best corrected visual acuity significantly improved in both groups by ∼ 0.26 logMAR units in control and diabetic groups (P &lt;0.001 for both). The mean change in central subfoveal thickness was 23.44±43.7 versus 13.6±22 um (P=0.3) in the control group and the diabetic group, respectively but statistically insignificant. There was insignificant change in each group in all vascular parameters during the follow-up period. In addition, there was insignificant difference between the two groups at each visit in most vascular parameters of superficial vessel density, deep vessel density (DVD), and choriocapillaris vessel density (CC VD). On the other hand, the diabetic groups have significantly lower superficial vessel density of whole image and perifovea at 1 week than controls (42.92±4.54% vs. 46.16±3.98%, P=0.01 in the whole image, respectively) (44.29±4.87% vs. 47.32±3.85%, P=0.018 in perifovea, respectively). The diabetic group also showed significantly higher parafoveal deep vessel density than the control group at 1 month postoperatively: 52.67±4.00 versus 47.24±9.85% (P=0.014) that leveled up on month 3 and 6 (P=0.397, 0.538, respectively). The diabetic group showed lower CC VD of the whole image than the control group at 1 week postoperatively: 70.60±2.87 versus 72.22±1.98%, respectively (P=0.025), and also significantly lower CC VD of perifovea than the control group at 1 week: 71.19±2.82 versus 72.72±2.20% (P=0.038), 1 month: 71.08±2.87 versus 72.78±2.61% (P=0.033) and 3 months: 71.35±2.63 versus 72.83±2.52% (P=0.048). Those values leveled up at the last postoperative visit at month 6 (P=0.152). Conclusion Phacoemulsification surgery may lead to the transient and mild reduction of choroidal blood flow in diabetic eyes rather than retinal blood flow. Most of choroidal and retinal vascular changes happened in the perifoveal area within 1 week to 1 month postoperatively and rarely extended to 3 months.

Development and validation of novel retina biomarkers and artificial intelligence models for Behçet disease uveitis prediction

ObjectiveThe aim of this study was to develop and validate quantitative diagnostic biomarkers and artificial intelligence (AI) models for Behçet disease uveitis (BU). MethodsWe conducted a single-center retrospective study using AI-based algorithms to evaluate OCT angiography (OCTA) fundus scans from 62 BU patients and 61 healthy individuals. ResultsFrom the 837 radiomic features derived from the OCTA scans, the top 20 features were utilized for AI modeling. The neural network (NN) model displayed the highest area under the receiver operating characteristic curve (AUC) of 0.900 in the test set. The integration of clinical data further enhanced the model's performance, leading to an AUC of 0.908 in the temporal validation cohort. ConclusionOur research demonstrates that the radiomic score and the clinical integrated score can independently serve as diagnostic biomarkers for BU for future potential clinical translational research. SignificanceThe AI models we developed show great promise for clinical and translational research, marking progress towards fulfilling the demand for quantitative imaging biomarkers in BU diagnosis. However, further validation and evaluation are crucial to confirm their real-world applicability in clinical settings.

Retinal vasculature of different diameters and plexuses exhibit distinct vulnerability in varying severity of diabetic retinopathy.

To study the changes in vessel densities (VD) stratified by vessel diameter in the retinal superficial and deep vascular complexes (SVC/DVC) using optical coherence tomography angiography (OCTA) images obtained from people with diabetes and age-matched healthy controls. We quantified the VD based on vessel diameter categorized as <10, 10-20 and >20 μm in the SVC/DVC obtained on 3 × 3 mm2 OCTA scans using a deep learning-based segmentation and vascular graph extraction tool in people with diabetes and age-matched healthy controls. OCTA images obtained from 854 eyes of 854 subjects were divided into 5 groups: healthy controls (n = 555); people with diabetes with no diabetic retinopathy (DR, n = 90), mild and moderate non-proliferative DR (NPDR) (n = 96), severe NPDR (n = 42) and proliferative DR (PDR) (n = 71). Both SVC and DVC showed significant decrease in VD with increasing DR severity (p < 0.001). The largest difference was observed in the <10 μm vessels of the SVC between healthy controls and no DR (13.9% lower in no DR, p < 0.001). Progressive decrease in <10 μm vessels of the SVC and DVC was seen with increasing DR severity (p < 0.001). However, 10-20 μm vessels only showed decline in the DVC, but not the SVC (p < 0.001) and there was no change observed in the >20 μm vessels in either plexus. Our findings suggest that OCTA is able to demonstrate a distinct vulnerability of the smallest retinal vessels in both plexuses that worsens with increasing severity of DR.

MORPHOLOGICAL BIOMARKERS PREDICTING EXUDATIVE CONVERSION IN TYPE 1 NONEXUDATIVE MACULAR NEOVASCULARIZATION USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

To investigate the incidence and morphological biomarkers to predict the exudative conversion in eyes with type 1 nonexudative macular neovascularization using swept-source optical coherence tomography angiography. Macular neovascularizations were detected using the retinal pigment epithelium-to-retinal pigment epithelium-fit slab of swept-source optical coherence tomography angiography scan. Depending on whether exudation developed within a year, the eyes were divided into two groups: active and silent. Qualitative and quantitative optical coherence tomography angiography parameters of the two groups were evaluated to discriminate the biomarkers associated with exudative conversion. Of the 40 eyes, nine developed exudation within 1 year (incidence rate 22.5%). The active group exhibited a significantly higher "anastomosis and loops" pattern, greater "vessel density," increased "junction density," fewer "number of end points," and lower "lacunarity" compared with the silent group. "Anastomosis and loops" and higher "vessel density" were correlated with the active group in multivariate analyses. A predictive model combining these biomarkers achieved 95% accuracy in predicting exudative conversion. At 12 months, the risk of exudation was 22.5%, and "anastomosis and loops" and "vessel density" were useful optical coherence tomography angiography biomarkers for predicting exudative conversion in eyes with type 1 nonexudative macular neovascularization. For eyes with a high risk of exudative conversion, more frequent follow-up is recommended.

Small Paracentral Acute Middle Maculopathy Lesions as Biomarker of Vascular Morbidity: Natural Course

Background: To evaluate the incidence rate of small paracentral acute middle maculopathy (PAMM) lesions in healthy fellow eyes of patients with retinal vein occlusions (RVO). Methods: Patients with unilateral branch RVO or central RVO who were followed up for at least one year were included. Fellow healthy eyes were examined with 6 mm optical coherence tomography angiography scans at baseline and at the end of the follow-up. Small resolved PAMM lesions were displayed using structural en face projections of the slab between two segmentation lines of the outer plexiform layer with 0 µm and −9 µm offset. New lesions were identified by overlaying baseline and final structural en face projections. Results: A total of 41 eyes of 41 patients (12 females and 29 males, mean age 63.5 ± 10.1 years) were included. The mean follow-up was 23.6 ± 11.4 months. Among all RVO patients, small resolved PAMM lesions in healthy fellow eyes were found in 39 patients (95.1%). In the whole cohort, the median number of PAMM lesions was 5.5 (95% CI 3.0 to 8.0) (mean 6.5 ± 5.7) at baseline, which increased statistically significantly to 5.5 (95% CI 3.8 to 8.2) (mean 6.7 ± 5.7) at the end of the follow-up period (p = 0.03). Eight (19.5%) patients demonstrated new lesions, with a median number of new lesions of 1 (ranged 1 to 2). Conclusions: Small PAMM lesions seem to be a slowly progressing retinal vascular biomarker.

Correlations between Retinal Microvascular Parameters and Clinical Parameters in Young Patients with Type 1 Diabetes Mellitus: An Optical Coherence Tomography Angiography Study

Objectives: In the current study, we investigated the correlations between retinal microvascular parameters using optical coherence tomography angiography (OCTA) and clinical parameters for a group of 69 young patients with type 1 diabetes mellitus (T1DM). Materials and Methods: This retrospective, exploratory study enrolled 69 patients between 5 years old and 30 years old who met the inclusion criteria. All the study participants underwent a comprehensive ophthalmic examination and OCTA scans for the evaluation of the retinal microcirculation. The retinal OCTA parameters were correlated with the following clinical parameters: the patient’s age at the onset of the disease, the duration of T1DM, the BMI at the time of enrollment in the study, the HbA1C values at onset, the mean values of HbA1C over the period of monitoring the disease and the degree of DKA at onset. Results: For the study group, the foveal avascular zone (FAZ) area and perimeter correlated positively with the mean value of HbA1C (Pearson correlation, Sig.2-Tailed Area: 0.044; perimeter: 0.049). The total vessel density in the superficial capillary plexus (SCP) correlated negatively with the duration of T1DM, based on the superior and inferior analyzed areas (Spearman correlation, Sig.2-Tailed SCP in total region: 0.002; SCP in the superior region: 0.024; SCP in the inferior region: 0.050). The foveal thickness also correlated negatively with the levels of diabetic ketoacidosis (DKA) at onset (Spearman correlation, Sig.2-Tailed: 0.034) and the levels of HbA1C at onset (Spearman correlation, Sig.2-Tailed: 0.047). Further on, the study patients were distributed into two groups according to the duration of the disease: group 1 included 32 patients with a duration of T1DM of less than 5 years, and group 2 included 37 patients with a duration of T1DM of more than 5 years. Independent t-tests were used to compare the OCTA retinal parameters for the two subgroups. While the FAZ-related parameters did not show significant statistical differences between the two groups, the vessel densities in both the SCP and DCP were significantly lower in group 2. Conclusions: Our data suggest that specific alterations in OCTA imaging biomarkers correlate with various clinical parameters: the FAZ area and perimeter increase with higher mean values of HbA1C, leading to poor metabolic control. Moreover, the SCP total vessel density decreases as the duration of T1DM increases. Regarding the vessel densities in the SCP and the DCP, they decrease with a duration of the disease of more than 5 years.

Choriocapillaris and Retinal Vascular Alterations in Presymptomatic Alzheimer's Disease.

To compare optical coherence tomography angiography (OCTA) retina metrics between cognitively healthy subjects with pathological versus normal cerebrospinal fluid (CSF) Aβ42/tau ratios. Swept-source OCTA scans were collected using the Zeiss PLEX Elite 9000 and analyzed on 23 cognitively healthy (CH) subjects who had previously undergone CSF analysis. Thirteen subjects had a pathological Aβ42/tau (PAT) ratio of <2.7132, indicative of presymptomatic Alzheimer's disease (AD), and 10 had a normal Aβ42/tau (NAT) ratio of ≥2.7132. OCTA en face images of the superficial vascular complex (SVC) and deep vascular complex were binarized and skeletonized to quantify the perfusion density (PD), vessel length density (VLD), and fractal dimension (FrD). The foveal avascular zone (FAZ) area was calculated using the SVC slab. Choriocapillaris flow deficits (CCFDs) were computed from the en face OCTA slab of the CC. The above parameters were compared between CH-PATs and CH-NATs. Compared to CH-NATs, CH-PATs showed significantly decreased PD, VLD, and FrD in the SVC, with a significantly increased FAZ area and CCFDs. Swept-source OCTA analysis of the SVC and CC suggests a significant vascular loss at the CH stage of pre-AD that might be an indicator of a neurodegenerative process initiated by the impaired clearance of Aβ42 in the blood vessel wall and by phosphorylated tau accumulation in the perivascular spaces, a process that most likely mirrors that in the brain. If confirmed in larger longitudinal studies, OCTA retinal and inner choroidal metrics may be important biomarkers for assessing presymptomatic AD.

Automated evaluation of parapapillary choroidal microvasculature in crowded optic discs: a controlled, optical coherence tomography angiography study.

To compare superficial and deep vascular properties of optic discs between crowded discs and controls using optical coherence tomography angiography (OCT-A). Thirty patients with crowded discs, and 47 control subjects were enrolled in the study. One eye of each individual was included and OCT-A scans of optic discs were obtained in a 4.5×4.5 mm2 rectangular area. Radial peripapillary capillary (RPC) density, peripapillary retinal nerve fiber layer (pRNFL) thickness, cup volume, rim area, disc area, cup-to-disc (c/d) area ratio, and vertical c/d ratio were obtained automatically using device software. Automated parapapillary choroidal microvasculature (PPCMv) density was calculated using MATLAB software. When the vertical c/d ratio of the optic disc was absent or small cup, it was considered as a crowded disc. The mean signal strength index of OCT-A images was similar between the crowded discs and control eyes (P=0.740). There was no difference in pRNFL between the two groups (P=0.102). There were no differences in RPC density in whole image (P=0.826) and peripapillary region (P=0.923), but inside disc RPC density was higher in crowded optic discs (P=0.003). The PPCMv density in the inner-hemisuperior region was also lower in crowded discs (P=0.026). The pRNFL thickness was positively correlated with peripapillary RPC density (r=0.498, P<0.001). The inside disc RPC density was negatively correlated with c/d area ratio (r=-0.341, P=0.002). The higher inside disc RPC density and lower inner-hemisuperior PPCMv density are found in eyes with crowded optic discs.

Features of Peripapillary Hyperreflective Ovoid Mass-Like Structures in Nonarteritic Anterior Ischemic Optic Neuropathy Patients and Normal Controls.

To determine the characteristics of peripapillary hyperreflective ovoid mass-like structures (PHOMS) in patients with nonarteritic anterior ischemic optic neuropathy (NAION) and in normal adults. A total of 406 included eyes were divided into four groups: acute NAION group, chronic NAION group, unaffected group, and normal eyes group. PHOMS were detected on optical coherence tomography slices from optical coherence tomography angiography scans centered on the optic nerve head (ONH). The differences in age, sex, and ONH parameters were investigated between eyes with PHOMS and eyes without PHOMS among groups. The prevalence of PHOMS in acute eyes (43.48%) and fellow eyes (28.20%) was significantly higher than that in normal eyes (11.76%) (acute vs. normal, P < 0.001; fellow vs. normal, P = 0.014). In the acute group, the PHOMS score of size was negatively correlated with age in acute eyes (r = -0.486, P = 0.03). The size of PHOMS was negatively correlated with age and cup/disc ratio and positively correlated with retinal nerve fiber layer thickness in the nasal and inferior sectors in the normal groups. No differences in age, sex, ONH parameters, or visual field defects were found between eyes with PHOMS and eyes without PHOMS. The prevalence of PHOMS increased significantly in acute nonoptic disc drusen (NODD)-NAION eyes and fellow eyes. PHOMS could also be found among normal adults. PHOMS may be a nonspecific sign secondary to ONH edema and axoplasmic stasis. The high prevalence of PHOMS in acute NODD-NAION eyes may indicate axoplasmic stasis secondary to tissue edema.

A Case of Full Thickness Parafoveal Hole Associated with Chorio-Retinal Atrophy

Background: An idiopathic full-thickness parafoveal hole (PFH) in the absence of trauma or intraocular surgery is a rare finding. Case: A 60-year-female who did not gain good vision following an uneventful phacoemulsification with intraocular lens (IOL) implantation in the right eye (RE) consulted a retina specialist, one year after her cataract surgery. There was no history of trauma, radiation exposure, reduced scotopic vision, or any other intraocular surgery. Her personal and family history were unremarkable for any systemic or ocular diseases. Routine blood investigations, an electrocardiogram, and a detailed ocular examination were done. Observation: She had the best corrected visual acuity (BCVA) of LogMAR 1.0 (20/200; 6/60) in the right eye. The right eye had an axial length (AL) of 23.50 mm and an intraocular lens power of 21.0 dioptres. The ultrawide field fundus examination saw parafoveal chorio-retinal atrophy without significant peripheral myopic degeneration. On optical coherence tomography (OCT), a central foveal thickness of 138 microns with foveal scarring was noticed. There was a full-thickness parafoveal hole between the fovea and optic disc having a height of 198 microns; base diameter of 240 microns; arm lengths of 203 microns and 206 microns; and a minimum linear dimension of 42 microns. The optical coherence tomography angiography scan showed a reduced vessel density in the superficial and deep retina; and increased visibility of choroidal vessels in outer retina chorio-capillaries, chorio-capillaries, and choroid slab at the parafoveal hole The ultrasound B scan was anechoic and there was no posterior vitreous detachment (PVD). Conclusion: The axial length, intraocular lens power and fundus examination did not indicate pathological myopia. As there was no preceding posterior vitreous detachment or retinal surgery, the underlying retinochoroidal atrophy most probably caused the full-thickness parafoveal hole.

Optical coherence tomography-angiography for anterior uveal tract evaluation in normal subjects and in pathology

Purpose: to assess the potentials of optical coherence tomography-angiography (OCTA) in the evaluation of anterior segment (AS) uveal vessels in normal and pathological conditions.Material and methods. 20 healthy volunteers (40 eyes) with no ophthalmic pathology (the control group) and 85 previously untreated patients (85 eyes) with suspected tumors of the irido-ciliary area (the iris, the ciliary body and the peripheral sections of the choroid) were examined. All participants had optical coherence tomography (OCT) and OCTA of AS, with the qualitative assessment of scans (vessels pattern, lumen, tortuosity) and the quantitative assessment (vessel density index, VD%, for the affected zone). In ciliary body or choroid pathologies, VD index was measured for the conjunctiva in the focus projection. VD index included mean and local VD, as well as VD of perifocal tissues. In addition, B-mode ultrasound scanning and ultrasound biomicroscopy were performed.Results. OCTA scans in 4 sectors of the normal iris showed a predominantly radial pattern of conjunctival vessels positioning, with their lumen remaining the same along their entire visible length. The lowest VD value (38.5%) was registered in the temporal iris segment, while the highest (43.9%) was revealed in the inferior quadrant. In the iris tumors area, intrinsic vascularity molded in various vascular patterns was observed. Melanomas could be suspected because of the vessels oriented along the axis of the tumor and by non-uniform lumen of the vessels.Conclusion. AS-OCTA is an informative method for the visualization of iris vessels in normal conditions and in iris pathology and may be considered a valuable addition to the standard visualization techniques.

Parapapillary choroidal microvasculature in retrobulbar optic neuritis: An optical coherence tomography angiography study

PurposeTo compare superficial and deep vascular characteristics of the optic disc in retrobulbar optic neuritis using optical coherence tomography angiography (OCT-A). MethodsNineteen patients with unilateral non-infectious retrobulbar neuritis were included in the study. The contralateral eyes of each patient were served as controls. OCT-A scans of the optic discs were performed in a 4.5 × 4.5 mm rectangular area, while macular OCT-A scans were performed in a 6 × 6 mm rectangular area. Various parameters, including radial peripapillary capillary (RPC) density, peripapillary retinal nerve fibre layer (pRNFL) thickness, cup volume, rim area, disc area, cup-to-disc (c/d) area ratio, and vertical and horizontal c/d ratios were automatically obtained using the instrument software. The density for superficial capillary plexus (SCP) and deep capillary plexus (DCP) were assessed using macular OCT-A. Parapapillary choroidal microvascular (PPCMv) density was calculated using MATLAB software. ResultsParafoveal inferior, perifoveal total and inferior SCP densities were significantly decreased in eyes with optic neuritis when compared with contralateral control eyes in OCT-A measurements (respectively, p = 0.027, p = 0.041, p = 0.045). The axial lengths, (p = 0.72), vertical and horizontal cup-disc ratios, and disc area, cup-disc areas, cup volumes, and pRNFL thicknesses between the groups were similar (for each, p>0.05). ConclusionsThis study demonstrated for the first time that patients with retrobulbar optic neuritis had decreased SCP densities, though it did not cause any changes in PPCMv density.

Reduction in retinal microvascular perfusion during migraine attacks.

To determine if there are changes in structure and function of the retinal vasculature during and between migraine attacks using optical coherence tomography angiography (OCTA). Migraine attacks commonly include visual symptoms, but the potential role of the retina in these symptoms is not well understood. OCTA is a rapid, non-invasive imaging technique that is used to visualize the retinal microvasculature with high spatial resolution in a clinical setting. In this study we used OCTA to quantify different features of the retinal vasculature in patients with migraine during and between attacks, as well as in healthy controls (HCs). We performed a prospective cohort study of 37 patients with migraine with aura (MA) (median [interquartile range, IQR] age of 37 [14] years, 86% female) and 30with migraine without aura (MO) (median [IQR] age of 37 [17] years, 77% female) and 20 HCs (median [IQR] age of 35 [7] years, 50% female). Macular OCTA scans were obtained for all participants for the interictal analysis. In 12 MA and eight MO, scans were captured both during and outside of migraine attacks and five HCs had initial and repeat scans. In addition to analyzing the morphology of the foveal avascular zone, we calculated the vessel flux index (VFI), which is an indicator of retinal perfusion and conventional metrics (such as vessel area density) in the foveal and parafoveal regions. There was a significant difference in the parafoveal VFI in the ictal state between the groups (p = 0.009). During migraine attacks there was a significant reduction in the parafoveal region VFI in MA (-7%, 95% confidence interval [CI] -10% to -4%; p = 0.006) and MO (-7%, 95% CI -10% to -3%; p = 0.016) from their interictal baseline as compared to the change between repeat scans in HCs (2%, 95% CI -3% to 7%). Interictally, there was a mean (standard deviation [SD]) 13% (10%) (p = 0.003) lower blood perfusion in the MA group as compared to the MO group in the foveal region (mean [SD] 0.093 [0.023] vs. 0.107 [0.021], p = 0.003). Interictal analysis also revealed higher circularity in the superficial foveal avascular zone in the MA group compared with the MO group (mean [SD] 0.686 [0.088] vs. 0.629 [0.120], p = 0.004). In addition, interictal analysis of the patients with MA or MO and unilateral headache showed increased retinal vascular parameters consistent with greater perfusion in the eye ipsilateral to the side of the pain as compared with the contralateral eye. These results indicate that perfusion is reduced in MA and MO in the parafoveal retina during the ictal period. Interictally, the foveal retina in MA has reduced perfusion when compared to the foveal retina in MO. Patients with unilateral headache showed interictal asymmetry of retinal perfusion between eyes. These results indicate that changes in retinal perfusion could be a part of migraine pathophysiology, and that distinct retinal vascular signatures identified with OCTA could represent biomarkers for migraine.

The Impact of Diabetic Retinopathy on the Choriocapillaris in Neovascular AMD.

To investigate the impact of diabetic retinopathy (DR) on morphological choriocapillaris (CC) modifications in eyes with type 1 macular neovascularization (MNV) secondary to AMD using optical coherence tomography angiography (OCTA). Eyes with AMD-related type 1 MNV with and without DR were prospectively included. We performed 3 × 3mm OCTA scans at two visits: before the loading phase of intravitreal injections of aflibercept (T1) and 1month after the last injection (T2). OCTA En face flow images of the CC were analyzed for flow deficit percentage (FD%), FD average area and FD number in a 500-µm-wide ring surrounding the dark halo (DH) around type 1 MNV. A total of 65 eyes, out of which 30 eyes had mild DR, were included. In the group without diabetes, there was a gradual reduction in FD% in the CC ring around the DH after antiangiogenic therapy, indicating reperfusion of the CC (P = 0.003). However, in the DR group, there were no significant changes in CC parameters between the two study visits. Specifically, the FD% in the CC ring around the DH did not show a significant reduction at T2 compared with T1 values (P > 0.05). Furthermore, the comparison of the variation in FD% between the two groups was statistically significant. The nondiabetic group exhibited a gradual CC reperfusion after the loading phase of aflibercept, whereas the diabetic eyes did not show significant changes (P = 0.029). The CC surrounding the DH associated to type 1 MNV exhibited greater hypoperfusion in diabetic eyes compared with eyes without diabetes, both before starting therapy and after the loading phase. Hence, DR may be a potential risk factor in the development and progression of late-stage AMD and may also influence the response to antiangiogenic therapy.

Optical coherence tomography angiography of choroidal neovascularization in long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD)

PurposeTo report the clinical utility of optical coherence tomography angiography (OCTA) for demonstrating choroidal neovascularization (CNV) associated with Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase Deficiency (LCHADD) retinopathy. MethodsThirty-three participants with LCHADD (age 7–36 years; median 17) were imaged with OCTA and the Center for Ophthalmic Optics & Lasers Angiography Reading Toolkit (COOL-ART) software was implemented to process OCTA scans. ResultsSeven participants (21 %; age 17–36 years; median 25) with LCHADD retinopathy demonstrated evidence of CNV by retinal examination or presence of CNV within outer retinal tissue on OCTA scans covering 3 × 3 and/or 6 × 6-mm. These sub-clinical CNVs are adjacent to hyperpigmented areas in the posterior pole. CNV presented at stage 2 or later of LCHADD retinopathy prior to the disappearance of RPE pigment in the macula. ConclusionOCTA can be applied as a non-invasive method to evaluate the retinal and choroidal microvasculature. OCTA can reveal CNV in LCHADD even when the clinical exam is inconclusive. These data suggest that the incidence of CNV is greater than expected and can occur even in the early stages of LCHADD retinopathy.