Capillary Perfusion Density Research Articles

Angioarchitectural alterations in the retina and choroid in frontotemporal dementia.

Frontotemporal dementia (FTD) is a progressive neurodegenerative disorder that affects the frontal and temporal lobes of the brain, leading to cognitive decline and personality changes. The objective of this cross-sectional study was to characterize angioarchitectural changes in the retina and choroid of individuals with FTD compared to cognitively normal controls using optical coherence tomography (OCT) and OCT angiography (OCTA). Cross-sectional comparison of patients with FTD and controls with normal cognition. All participants underwent Mini-Mental State Examination (MMSE) at the time of imaging. Outcome measures included OCT parameters: retinal nerve fiber layer (RNFL) thickness, ganglion cell layer-inner plexiform layer (GC-IPL) thickness, central subfield thickness (CST), subfoveal choroidal thickness (SFCT), choroidal vascularity index (CVI); and OCTA superficial capillary plexus parameters: foveal avascular zone (FAZ) area, 3x3mm and 6x6mm macular perfusion density (PD) and vessel density (VD), 4.5x4.5mm peripapillary capillary perfusion density (CPD) and capillary flux index (CFI). Generalized estimating equation analysis was used to account for the inclusion of 2 eyes from the same participant. 29 eyes of 19 patients with FTD and 85 eyes of 48 controls were analyzed. In FTD, 3x3mm macular PD (p = 0.02) and VD (p = 0.02) and CFI (p = 0.01) were reduced compared to controls. There was no difference in average 4.5x4.5mm CPD, RNFL thickness, GC-IPL thickness, CST, SFCT, CVI, FAZ, or 6x6mm VD or PD between FTD and controls (all p > 0.05); however, there was a trend toward lower macular 6x6mm PD and VD in patients with FTD. Decline of peripapillary and macular OCT and OCTA parameters merit further investigation as potential biomarkers for FTD detection. Noninvasive retinal and choroidal imaging may hold promise for earlier detection, and future longitudinal studies will clarify their role in monitoring of FTD.

Macular, Choroidal, and Peripapillary Perfusion Changes in Mild and Moderate Traumatic Brain Injury Using Optical Coherence Tomography and Angiography.

Introduction: To compare the retinal and choroidal architecture and microvasculature between patients with mild or moderate traumatic brain injury (TBI) and controls with normal cognition using optical coherence tomography (OCT) and OCT angiography (OCTA). Methods: Patients with a documented history of TBI, and age-matched and sex-matched controls were recruited. The primary outcome measures were differences between OCT parameters, including the choroidal vascularity index, and between OCTA superficial capillary plexus metrics, including foveal avascular zone (FAZ) circularity, 3.0 mm × 3.0 mm and 6.0 mm × 6.0 mm macular vessel density and perfusion density, and 4.5 mm × 4.5 mm peripapillary capillary perfusion density and capillary flux index. Results: Sixty-seven eyes of 36 patients with TBI and 72 eyes of 36 control patients met the inclusion criteria. Twelve patients (33.3%) had a diagnosis of mild TBI without loss of consciousness (LOC), 21 (58.3%) had mild TBI with LOC, and 3 (8.3%) had moderate TBI. There was a significant reduction in FAZ circularity and in 3.0 mm × 3.0 mm macular OCTA vessel density and perfusion density in patients with TBI. In cases with TBI associated with posttraumatic stress disorder, all macular OCTA parameters were significantly reduced. There was an increase in the choroidal vascularity index across the severity of TBI; however, it was reduced in those with more than 1 TBI (P = .03). Conclusions: There was a reduction in macular perfusion in eyes of patients with mild or moderate TBI. The choroidal vascularity index helps differentiate subtle effects of more severe or mild repeated TBI. Further prospective investigation will evaluate OCT imaging and OCTA imaging as a noninvasive screening modalities to assess changes in retinal and choroidal microvasculature.

OCTA: Essential or Gimmick?

This commentary article delves into the transformative role of optical coherence tomography angiography (OCTA) in diagnosing and managing a wide array of eye conditions, including diabetic retinopathy, age-related macular degeneration, retinal vein occlusions, and white dot syndromes. Developed in 2005, OCTA has emerged as a non-invasive, high-resolution imaging technique that offers advantages over traditional fluorescein angiography (FA), providing quicker and safer monitoring of ocular conditions with similar diagnostic accuracy. In diabetic retinopathy, OCTA has been instrumental in early identification of retinal changes, offering quantifiable metrics including perfused capillary density (PCD) for assessing vascular alterations. For age-related macular degeneration (AMD), OCTA has deepened our understanding of non-exudative neovascular AMD, allowing for more effective monitoring and potential earlier initiation of treatment. In cases of retinal vein occlusions, OCTA can reveal specific microvascular features and allow for depth-resolved measurements of the foveal avascular zone, providing significant prognostic implications. OCTA has also been invaluable in studying rare white dot syndromes, enabling nuanced differentiation between conditions that often present similarly. Emerging research also suggests that OCTA can have potential utility in neurodegenerative diseases like Alzheimer's, where retinal vascular patterns could offer diagnostic insights. While OCTA is revolutionizing ophthalmic care, further clinical trials and standardization are needed for its broader adoption into clinical practice.

A gender-based analysis of retinal microvascular alterations in patients with diabetes mellitus using OCT angiography

PurposeTo assess the difference in microvascular changes between males and females with diabetes mellitus (DM) without diabetic retinopathy (NoDR) and with mild-to-moderate non-proliferative diabetic retinopathy (NPDR) using Optical Coherence Tomography Angiography (OCT-A). DesignRetrospective cross-sectional study. Methods267 DM patients, 133 females (49.81 %), 111 with NoDR (41.57 %) and 156 NPDR (58.43 %) were included. Foveal-centered 3 × 3 mm OCT-A images corresponding to the superficial (SCP), intermediate (ICP) and deep capillary plexus (DCP), and full retinal (RET) slab were used for analysis. For each slab, FAZ area, perimeter, and circularity index (CI) were determined, following manual delineation of the FAZ; perfusion (PD) and vessel density (VD), fractal dimension (FD), vessel length density (VLD), geometric perfusion deficits (GPD) were also computed. Flow voids (FV) were determined in the choriocapillaris plexus; and perfused capillary density (PCD) in the RET slab. ResultsFemales showed larger FAZ CI in SCP and greater FAZ area and perimeter than males in NPDR group. Males had higher central macular thickness than females in NPDR group. All density metrics at the level of ICP and DCP were affected in the NPDR group with no gender differences. Of note, the same significant findings were found in type 1 DM patients, and not in type 2 DM patients. ConclusionsOur OCT-A findings suggest significant microvascular changes in females with NPDR compared to males, but no such differences in patients without DR. Therefore, gender-related vascular alterations might be present in early stages of DR with potential role.

Efficacy and safety of platelet-rich plasma for acute nonarteritic anterior ischemic optic neuropathy: a prospective cohort study.

As the most common acute optic neuropathy in older patients, nonarteritic anterior ischemic optic neuropathy (NAION) presents with varying degrees of visual acuity loss and visual field defect. However, there is no generally accepted treatment for NAION. To evaluate the efficacy and safety of platelet-rich plasma (PRP) for patients with acute NAION within 2 months. A prospective, nonrandomized controlled trial. Twenty-five eyes of 25 patients were enrolled. Of them, 13 received anisodine hydrobromide and butylphthalide-sodium chloride injection continuously for 10 days as basic treatment in the control group, and 12 received two tenon capsule injections of PRP on a 10 days interval as an additional treatment in the PRP group. We compared the best-corrected visual acuity (BCVA) and capillary perfusion density (CPD) of radial peripapillary capillaries and the moth-eaten eara of the peripapillary superficial capillary plexus and deep capillary plexus at 1 day (D1) before the first PRP treatment and 7 days (D7), 14 days (D14), and 30 days (D30) after the first PRP injection. Ocular and systemic adverse effects were assessed. In the PRP group, a better BCVA occurred at D30 (adjusted p = 0.005, compared with D1, recovered from 0.67 ± 0.59 to 0.43 ± 0.59), and a significant improvement in CPD was observed at D30 (adjusted p < 0.001, p = 0.027, p = 0.027, compared with D1, D7, D14, in sequence, the value was 35.97 ± 4.65, 38.73 ± 4.61, 39.05 ± 5.26, 42.71 ± 4.72, respectively). CPD at D7 in the PRP group was better than that in the control group (p = 0.043). However, neither BCVA nor the moth-eaten area index were significantly different (all p > 0.5) between the two groups. The main adverse effect was local discomfort resolved within 1 week, and no other systemic adverse events occurred. Tenon capsule injection of PRP was a safe treatment for AION and could improve capillary perfusion of the optic nerve head and might be helpful in increasing short-term vision in patients with acute NAION.

Longitudinal Assessment of Peripapillary Microvasculature Using Optical Coherence Tomography Angiography in Cognitively Normal Adults.

Introduction: To evaluate longitudinal peripapillary changes in cognitively normal older adults using optical coherence tomography (OCT) and OCT angiography (OCTA). Methods: Participants older than 50 years with no history of neurodegenerative disease or cognitive impairment were prospectively enrolled. OCT and OCTA images were obtained at the first visit and 2 years later. Results: The study comprised 189 eyes of 111 adults with a mean age (±SD) of 69.3 ± 5.8 years and mean follow-up of 2.1 ± 0.5 years. Woman experienced slower rate of decline than men in capillary perfusion density (0.000% ± 0.005% vs -0.002% ± 0.004%; P = .038) and retinal nerve fiber layer (RNFL) thickness (0.133 ± 1.617 µm vs -0.659 ± 1.431 µm; P = .008). At both timepoints, after controlling for sex, the capillary perfusion density (P < .001), capillary flux index (P < .001), and RNFL thickness (P = .005) were lower in older participants. The mean capillary perfusion density was higher in women than in men at both timepoints (P = .01 and P = .002, respectively), with no significant differences in the capillary flux index and RNFL thickness. Conclusions: In cognitively normal adults, there is a significant reduction in peripapillary capillary perfusion density, the capillary flux index, and RNFL thickness associated with aging beyond 50 years. Women had higher capillary perfusion density values with slower rates of change in capillary perfusion density and RNFL thickness. These values can serve as benchmarks, and variations could be suspicious for a pathologic process.

Peripapillary Optical Coherence Tomography Angiography in Alzheimer's Disease, Mild Cognitive Impairment, and Normal Cognition.

This study aimed to identify peripapillary microvascular changes in Alzheimer's disease (AD) and mild cognitive impairment (MCI). In this prospective study, 66 eyes of 36 subjects with AD, 119 eyes of 63 with MCI, and 513 eyes of 265 controls with normal cognition were enrolled. Peripapillary capillary perfusion density (CPD), capillary flux index (CFI), and retinal nerve fiber layer (RNFL) thickness were determined. Average CPD differed significantly between all three groups (P = 0.001), being significantly greater in AD vs controls (0.446 ± 0.015 vs 0.439 ± 0.017, P = 0.001) and MCI vs controls (0.443 ± 0.020 vs 0.439 ± 0.017, P = 0.007) but not AD vs MCI (P = 0.69). CFI and average RNFL thickness did not significantly differ among groups (all P > 0.05). Peripapillary CPD is increased in eyes with AD or MCI compared to controls despite similar RNFL thickness. [Ophthalmic Surg Lasers Imaging Retina 2024;55:78-84.].

Characterizing differences in retinal and choroidal microvasculature and structure in individuals with Huntington's Disease compared to healthy controls: A cross-sectional prospective study.

To characterize retinal and choroidal microvascular and structural changes in patients who are gene positive for mutant huntingtin protein (mHtt) with symptoms of Huntington's Disease (HD). This study is a cross-sectional comparison of patients who are gene positive for mHtt and exhibit symptoms of HD, either motor manifest or prodromal (HD group), and cognitively normal individuals without a family history of HD (control group). HD patients were diagnosed by Duke movement disorder neurologists based on the Unified Huntington's Disease Rating Scale (UHDRS). Fovea and optic nerve centered OCT and OCTA images were captured using Zeiss Cirrus HD-5000 with AngioPlex. Outcome metrics included central subfield thickness (CST), peripapillary retinal nerve fiber layer (pRNFL) thickness, ganglion cell-inner plexiform layer (GCIPL) thickness, and choroidal vascularity index (CVI) on OCT, and foveal avascular zone (FAZ) area, vessel density (VD), perfusion density (PD), capillary perfusion density (CPD), and capillary flux index (CFI) on OCTA. Generalized estimating equation (GEE) models were used to account for inter-eye correlation. Forty-four eyes of 23 patients in the HD group and 77 eyes of 39 patients in the control group were analyzed. Average GCIPL thickness and FAZ area were decreased in the HD group compared to controls (p = 0.001, p < 0.001). No other imaging metrics were significantly different between groups. Patients in the HD group had decreased GCIPL thickness and smaller FAZ area, highlighting the potential use of retinal biomarkers in detecting neurodegenerative changes in HD.

Correlation Between Optical Coherence Tomography Angiography Findings at 3 to 6 Weeks and Functional Outcome at 3 Months Following Acute Ischaemic Stroke Due to Extracranial Carotid Artery Atherosclerotic Disease

ABSTRACT We wanted to evaluate if optical coherence tomography angiography OCTA findings could predict the functional outcome in extracranial carotid artery atherosclerotic disease (ECAD) associated stroke. This exploratory study was performed on adults with acute ischaemic stroke due to ECAD at 3–6 weeks following stroke onset with risk factor matched controls without carotid artery stenosis. Twenty-three stroke patients (cases) and 23 controls were enrolled. There was significant difference between cases and controls in deep vessel density at the macula (p = .0007) and in radial peripapillary capillary perfusion density (RPCPD) at the optic nerve head (ONH) (p = .0007). Statistically significant difference was noted in the total superficial vessel density (SVD) at the macula (SVD within 1 standard deviation [SD] versus SVD beyond 1 SD of control data) in the ipsilateral eye and functional outcome at 3 months (poor versus very good outcome, modified Rankin scale [mRS] 0–1 versus mRS 2–6, respectively; p = .0361). There was statistically insignificant correlation between the RPCPD at the ONH and the National Institutes of Health Stroke Scale score at admission, mRS at discharge, and mRS at 3 months following stroke onset (r = .33, r = .35, r = .39; p = .11, p = .09, p = .06, respectively). The findings of this exploratory study suggested that OCTA findings may predict 3 month outcomes in cases of ECAD-related stroke and could be useful in decision making in future intervention studies as to whether intervene or not in patients having critical or non-critical ECAD for preventing stroke.

Risk factors and macular microvascular changes in open angle glaucoma progression: A longitudinal study using OCT‐A

Aims/Purpose: To investigate prospectively macular microvascular changes in patients with glaucoma and identify common characteristics among the progressive eyes.Methods: A 12‐month prospective longitudinal study was performed with 124 open‐angle‐glaucoma‐eyes (GE). Glaucomatous progression was defined as a decrease of ≥5 μm in average or ≥7 μm in a sector of RNFL thickness. OMAG OCT microangiography (Angioplex, HD OCT, Cirrus 5000, Zeiss) was used to analyse the macular region. The statistical analysis was performed using the SPSS version 23.0 statistical package (SPSS Inc., IL).Results: Among the GE group, 22.36% of eyes showed progression, being the decrease of the Complete Region Macular Vessel Density (MVD) and Macular Capillary Perfusion Density (MPD) greater (−1.14 mm/mm2 and −3.18%) compared to non‐progressive eyes (−0.42 mm/mm2 and −1.02%) [p = 0.123 and 0.057], being the temporal and superior sectors for both MVD and MPD, the ones that showed greater differences (−1.44 mm/mm2, −1.11 mm/mm2, −3.6% and −2.95% respectively) [p &gt; 0.05 for all]. Characteristics as elevated intraocular pressure (IOP) (17.29 vs 14.87 mmHg), thinner central corneal thickness (CCT) (521.53 vs 538.65 μm) and lower ocular perfusion pressure (OPP) (45.88 vs 49.21 mmHg) were significantly different in those progressive GE [p &lt; 0′05 for all]. Nevertheless, increased vertical cup to disc ratio (CDV) (0.64 vs 0.63) and minimum ganglion cell layer thickness (GCLM) (58,82 vs 56.51 μm) were not significantly different in progressive GE [p = 0.768 and 0.249].Conclusions: Data showed that when glaucomatous progression took place, stronger vascular changes occurred in the macular area, as greater decrease of MVD and MPD specially in the temporal and superior sectors. In addition, common characteristics as elevated intraocular pressure, thinner central corneal thickness and lower ocular perfusion pressure were identified in progressive GE. Nevertheless, further research with larger population and larger follow‐up is needed to obtain stronger results.

Multimodal retinal imaging in individuals with frontotemporal dementia compared to controls

AbstractBackgroundA growing body of literature has shown a relationship between neurodegenerative diseases and ocular changes. Frontotemporal dementia (FTD) affects individuals under age 65. We use optical coherence tomography (OCT) and OCT angiography (OCTA) to characterize the retinal microvasculature and retinal and choroidal structure in patients with FTD vs normal cognition.MethodCross‐sectional comparison of patients with FTD to age‐ and sex‐matched controls with normal cognition. Exclusion criteria included diabetes, glaucoma, uncontrolled hypertension, and retinal or optic nerve pathology. Participants underwent OCT and OCTA imaging using the Zeiss Cirrus HD‐5000 Spectral‐Domain OCT with AngioPlex. Primary outcome measures included OCT parameters: subfoveal choroidal thickness, central subfield thickness, ganglion cell layer‐inner plexiform layer (GC‐IPL) thickness, and retinal nerve fiber layer (RNFL) thickness; and OCTA parameters: superficial capillary plexus foveal avascular zone area, 3×3mm and 6×6mm macular vessel density (VD) and perfusion density (PD), and 4.5×4.5mm peripapillary capillary perfusion density (CPD) and capillary flux index (CFI). Generalized estimating equations accounting for correlation between 2 eyes of the same subject were utilized for statistical analysis.ResultTwenty‐eight eyes of 17 participants with FTD and 85 eyes of 48 patients with normal cognition were analyzed. Individuals with FTD were matched to their normal cognition counterparts with regard to sex (64.7% vs 62.5% men, p = 0.871) and age (67.82 vs 68.98 years, p = 0.958). Compared to normal cognition participants, MMSE scores of FTD participants were significantly lower (p &lt; 0.001). In FTD, average 4.5×4.5‐mm CFI was decreased compared to controls (p = 0.032). There was no difference in average 4.5×4.5mm CPD between FTD and controls (p = 0.172).ConclusionIndividuals with FTD exhibited significantly reduced average CFI compared to controls. Retinal microvasculature changes may be useful as a biomarker for FTD diagnosis.

Differences in Retinal and Choroidal Microvasculature and Structure in Dementia With Lewy Bodies Compared With Normal Cognition.

Purpose: To evaluate the retinal and choroidal microvasculature and structure in individuals with dementia with Lewy bodies (DLB) compared with controls with normal cognition using optical coherence tomography (OCT) and OCT angiography (OCTA). Methods: An institutional review board-approved cross-sectional comparison of patients with DLB and cognitively normal controls was performed. The Cirrus HD-OCT 5000 with AngioPlex (Carl Zeiss Meditec) was used to obtain OCT and OCTA images. Results: Thirty-four eyes of 18 patients with DLB and 85 eyes of 48 cognitively normal patients were analyzed. The average capillary perfusion density (CPD) was higher in the DLB group than in the control group (P = .005). The average capillary flux index (CFI) and ganglion cell inner-plexiform layer (GC-IPL) thickness were lower in the DLB group than in the control group (P = .016 and P = .040, respectively). Conclusions: Patients with DLB had an increased peripapillary CPD, decreased peripapillary CFI, and attenuated GC-IPL thickness compared with those with normal cognition.

Longitudinal Analysis of Retinal Microvascular and Choroidal Imaging Parameters in Parkinson's Disease Compared with Controls

To quantify rate of change of retinal microvascular and choroidal structural parameters in subjects with Parkinson's disease (PD) compared with controls using OCT and OCT angiography (OCTA). Prospective longitudinal study. Seventy-four eyes of 40 participants with PD and 149 eyes of 78 control individuals from the Eye Multimodal Imaging in Neurodegenerative Disease database. Subjects underwent OCT and OCTA imaging at 2 time points approximately 12 months apart. Imaging parameters included central subfield thickness, ganglion cell-inner plexiform layer (GC-IPL) thickness, peripapillary retinal nerve fiber layer thickness, choroidal vascularity index, superficial capillary plexus perfusion density (PFD), vessel density (VD), and foveal avascular zone area. Participants with PD had greater rate of yearly decrease in GC-IPL (PD=-0.403μm, control=+ 0.128 μm; P= 0.01), greater yearly decline in PFD in the 3× 3 mm ETDRS circle (PD=-0.016, control=+ 0.002; P<0.001) and ring (PD=-0.016, control=+ 0.002; P < 0.001); 6× 6 mm ETDRS circle (PD=-0.021, control= 0.00; P= 0.001), and outer ring (PD=-0.022, control= 0.00; P= 0.001). Participants with PD had greater rate of yearly decline in VD in 3× 3 mm circle (PD=-0.939/mm, control=+ 0.006/mm; P < 0.001) and ring (PD=-0.942/mm, control=+ 0.013/mm; P < 0.001); 6× 6 mm circle (PD=-0.72/mm, control=-0.054/mm; P= 0.006), and outer ring (PD=-0.746/mm, control=-0.054/mm; P= 0.005). When stratified by PD severity based on Hoehn and Yahr stage, faster rates of decline were seen in Hoehn and Yahr stages 3 to 4 in the 3× 3 mm circle PFD and VD as well as 3× 3 mm ring VD. Individuals with PD experience more rapid loss of retinal microvasculature quantified on OCTA and more rapid thinning of the GC-IPL than controls. There may be more rapid loss in patients with greater disease severity. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Detection of Relative Afferent Pupillary Defect and Its Correlation with Structural and Functional Asymmetry in Patients with Glaucoma Using Hitomiru, a Novel Hand-Held Pupillometer.

Patients with asymmetric glaucomatous optic neuropathy (GON) present a relative afferent pupillary defect (RAPD) in the eye with more advanced damage. Although useful, pupillometric RAPD quantification is not widely used as it is not portable. Whether asymmetry of the peripapillary capillary perfusion density (CPD) detected using optical coherence tomography angiography correlates with the severity of RAPD remains unknown. This study assessed RAPD in 81 patients with GON using Hitomiru, a novel hand-held infrared binocular pupillometer. The correlation and ability to detect clinical RAPD based on the swinging flash light test of two independent RAPD parameters (the maximum pupil constriction ratio and the constriction maintenance capacity ratio) were assessed. The coefficient of determination (R2) was calculated between each of the two RAPD parameters and asymmetry of the circumpapillary retinal nerve fiber layer thickness (cpRNFLT), ganglion cell layer/inner plexiform layer thickness (GCL/IPLT), and CPD. The two RAPD parameters showed a correlation coefficient of 0.86 and areas under the receiver operating characteristic (ROC) curve of 0.85-0.88, with R2 being 0.63-0.67 for the visual field, 0.35-0.45 for cpRNFLT, 0.45-0.49 for GCL/IPLT, and 0.53-0.59 for CPD asymmetry. Hitomiru has high discriminatory performance in detecting RAPD in patients with asymmetric GON. CPD asymmetry may better correlate with RAPD than cpRNFLT and GCL/IPLT asymmetry.

Acute and subacute intraocular pressure and macular microvascular structure changes after intravitreal ranibizumab injection in eyes with branch retinal vein occlusion

PurposeTo investigate early changes in the intraocular pressure (IOP) and macular microvascular structure in eyes with branch retinal vein occlusion (BRVO) treated with intravitreal Ranibizumab injection.MethodsThis study enrolled 30 patients (one eye per patient) who received intravitreal injections (IVI) of ranibizumab for macular edema secondary to BRVO. IOP were measured before, 30 min (min) and 1 month following IVI. Changes in macular microvascular structure were examined via assessment of foveal avascular zone (FAZ) parameters, vascular density (VD) of superficial vascular complex (SVC), and deep vascular complex (DVC) in whole macula, central fovea and parafovea area which were measured automatically by optical coherence tomography angiography (OCTA) on the same time as IOP examinations. Paired t test and Wilcoxon test were used to compare pre- and post-injection values. The correlation between IOP and OCTA findings was assessed.ResultsIOP Measurements at 30 min post-IVI (17.91 ± 3.36 mmHg) increased significantly from baseline (15.07 ± 2.58 mmHg, p < 0.001), then became similar with baseline after 1 month (15.00 ± 3.16 mmHg, p = 0.925). 30 min past the injection, the parameters of VD of the SCP significantly decreased in comparison to baseline, then became similar with baseline after one month, while there were no significant changes in other OCTA parameters, including parameters of VD of the DCP and the FAZ. At 1 month after IVI, in comparison to baseline, no significant changes were observed in all of the OCTA parameters (P > 0.05). There were no significant correlations between IOP and OCTA findings no matter 30 min or 1 month post-IVI (P > 0.05).ConclusionsTransient IOP elevation and decreased superficial macular capillary perfusion density were detected 30 min post-IVI, however, no potential continual macular microvascular damage was suspected.

Inner retinal layers' alterations of the microvasculature in early stages of Parkinson's disease: a cross sectional study.

To investigate microcirculation characteristics of the inner retinal layers at the macula and the peripapillary area using Optical Coherence Tomography Angiography (OCT-A) of patients in early stages of Parkinson's disease (PD). 32 PD patients and 46 age- and gender-matched healthy controls were included in this cross sectional study. OCT-A imaging was performed to analyze microcirculation characteristics at each separate macular region (fovea, parafovea, and perifovea) and the peripapillary area of the inner retinal layers. Individuals with PD had significantly lower parafoveal, perifoveal and total vessel density (VD) in the superficial capillary plexus (SCP) than controls (all p < 0.001), while foveal VD was higher in PD eyes than that of controls, though not statistically significant. Similarly, individuals with PD had significantly lower parafoveal, perifoveal and total perfusion in the SCP than control eyes (all p < 0.001), while foveal perfusion was significantly higher in PD eyes than that of controls (p = 0.008). PD eyes had significantly smaller FAZ area and perimeter accompanied by decreased circularity at the SCP as compared to controls (all p < 0.001). Concerning the peripapillary area, individuals with PD had significantly lower radial peripapillary capillary perfusion density and flux index at the SCP than controls (all p < 0.001). All p values remained statistically significant even after using the Bonferroni correction for multiple comparisons, except for that of foveal perfusion. Our study indicates alterations of the inner retinal layers at the macula and the peripapillary area at the preliminary stages of PD. OCT-A parameters could potentially comprise imaging biomarkers for PD screening and improve the diagnostic algorithms.

OCTA biomarkers in adults aged 50 and above: a prospective and cross-sectional community-based study

Background/AimsTo assess the normative values and parameters of optical coherence tomography angiography (OCTA) influencing the best corrected visual acuity (BCVA) in adults aged 50 and above.MethodsThis was a prospective cross-sectional study from an eye screening programme in Hong Kong for 4188 citizens aged 50 and above. Images were analysed using a validated quantification software calculating vessel density and capillary perfusion density (CPD), along with other OCTA parameters, such as the foveal avascular zone area (FAZ) and circularity. OCTA data was collected from May 2019 to December 2020, including a total of 4188 healthy eyes from 4188 subjects.ResultsMean superficial vessel density (MSVD) was 14.48 ± 3.60 mm− 1, while the mean capillary perfusion density (MCPD) was 0.41 ± 0.06. Multivariate analysis revealed ageing (β = 0.321, p < 0.001), being male (β=-0.089, p < 0.001), having a high body mass index (BMI) (β = 0.039, p = 0.006), high FAZ area and low FAZ circularity (β = 0.039 and − 0.034, p = 0.01 and 0.024 respectively), low MSVD in the outer ring (β=-0.513, p < 0.001), specifically in the nasal and temporal outer quadrants (β = -0.226 and − 0.259, p < 0.001 for both), and low MCPD in the outer superior quadrant (β= -0.123, p = 0.016) being independently associated with BCVA.ConclusionHigh FAZ area and low FAZ circularity, low MSVD in the outer ring, specifically the nasal and temporal outer quadrants, and low MCPD in the outer superior quadrant can be used as biomarkers in predicting a low visual acuity in adults aged 50 and above.

Macular and peripapillary microvascular changes in open angle glaucoma and ocular hypertension: A longitudinal study using optical coherence tomography angiography (OCT‐A)

AbstractPurpose: To investigate prospectively macular and peripapillary microvascular changes in patients with glaucoma and ocular hypertension.Methods: A 12‐month prospective longitudinal study was performed with 124 open‐angle‐glaucoma‐eyes (GE), 111 ocular‐hypertension‐eyes (OHE) and 98 gender and age matched control‐eyes (CE). Glaucomatous progression was defined as a decrease of ≥5 μm in average or ≥7 μm in a sector of RNFL thickness. OMAG OCT microangiography (Angioplex, HD OCT, Cirrus 5000, Zeiss) was used to analyse optic disc and macular regions. The statistical analysis was performed using Mann–Whitney‐Test with the SPSS version 23.0 statistical package (SPSS Inc., IL).Results: Among OHE and GE groups, 21.7% of eyes showed progression, being the decrease of Peripapillary Flux Index (PFI), Macular Vessel Density (MVD) and Macular Capillary Perfusion Density (MPD) greater (−0.0067; −0.696 mm/mm2 and −1.56%) compared to non‐progressive eyes (+0.0038; 0.527 mm/mm2 and 1.55%) being the nasal and inferior sectors for PFI, and the superior and temporal sectors for both MVD and MPD, the ones that showed greater differences [p = 0.015 and p &lt; 0.001 for the last two]. Furthermore, Peripapillary Perfusion Density (PPD) showed non‐significant greater decrease (−0.347) compared to non‐progressive eyes (−0.324) [p = 0.775]. Characteristics as increased vertical cup to disc ratio (CDV) (0.64 vs. 0.57), elevated intraocular pressure (IOP) (18.25 vs. 15.40 mmHg), thinner central corneal thickness (CCT) (520.18 vs. 541.67 μm) and lower ocular perfusion pressure (OPP) (47.81 vs. 48.95 mmHg) were significantly different in those progressive OHE and GE [p &lt; 0.05 for all]. Nevertheless, minimum ganglion cell layer thickness (GCLM) was only significantly lower in progressive GE (58.51 vs. 73.98 μm) [p = 0.036].Conclusions: Data showed that when glaucomatous progression took place, stronger microvascular changes occurred in the macular and peripapillary areas, as greater decrease of MVD, MPD and PFI, especially in superior and temporal sectors for the macular area, and in nasal and inferior sectors for the peripapillary area. Nevertheless, further research with larger population and larger follow‐up is needed to obtain stronger results.

Evaluation of Blood Flow Parameters of the Macular Area and Optic Disc in Patients with Combination of Glaucoma and Axial Myopia

Purpose. To analyze the indicators of blood flow in the macular region and the peripapillary region in patients with a combination of glaucoma and axial myopia.Patients and methods. The paper analyzes the results of a study of 186 patients (343 eyes): 51 patients (92 eyes) with axial myopia (mean AVR 26.3 ± 1.9 mm) and diagnosed with primary open-angle glaucoma of various stages (Glaucoma + Myopia group), 42 patients (78 eyes) with axial myopia (mean AVR 26.5 ± 1.8 mm) without other ophthalmopathology (Myopia group), 48 patients (86 eyes) with refraction close to emmetropic and primary open-angle glaucoma of various stages (Glaucoma group), 45 patients (87 eyes) without any ophthalmopathology and refraction close to emmetropic (Emmetropia group).Results. With the development of glaucoma, a decrease in the density of capillary perfusion and the density of vessels of the superficial plexus in the macular region was revealed, with a predominant decrease in the parameter in the lower sector, with a progressive decrease with the glaucoma severity. More pronounced deviations from the indicators of the control groups were recorded in the group of combined glaucoma and axial myopia. In the peripapillary region of patients with glaucoma, a decrease in capillary perfusion density and capillary flow index in the upper and especially in the lower sector was recorded, with more pronounced changes in the combination of the disease with axial myopia.Conclusion. The tomographic indicators of blood flow in the macular and peripapillary areas from this study can be used to obtain the most complete picture of the course of the glaucoma process in patients with different types of refraction, as well as for differential diagnosis and staging of glaucoma in high myopic eyes.

Multi-Center Repeatability of Macular Capillary Perfusion Density Using Optical Coherence Tomography Angiography.

Background/AimsThis study was to determine the test–retest repeatability in quantifying macular capillary perfusion density (CPD, expressed as fractal dimension) using optical coherence tomography angiography (OCTA) in a multi-center setting.MethodsOCTA data were obtained in self-reported healthy subjects from Bascom Palmer Eye Institute at the University of Miami (UM, N = 18) and the University of Pennsylvania (UPenn, N = 22). The right eye of each subject was imaged twice at the first visit and then again at an interval of one week to assess intra-visit and inter-visit repeatability. The macular area of the OCTA-derived capillary perfusion density (OCTA-CPD) was analyzed by custom-made image processing and fractal analysis software. Fractal analysis was performed on the skeletonized microvascular network to yield OCTA-CPD by box-counting to the fractal dimension (Dbox) in the superficial vascular plexus (SVP). Repeatability was assessed by three measures: within-subject standard deviation (Sw), coefficient of variation (CoV) of repeated measures, and intraclass correlation coefficient (ICC).ResultsOCTA-CPD from both sites (UM and UPENN) showed good to excellent intra-visit repeatability, as demonstrated by the Sw ≤0.004, CoVs ≤0.23%, and ICCs ≥0.61. Similarly, both sites had good to excellent inter-visit repeatability, as shown by the Sw ≤0.005, CoVs ≤0.28%, and ICCs ≥0.61. The Bland-Altman plots of the intra-visit and inter-visit measurements showed excellent agreements between the paired measurements with minimal biases.ConclusionOur data showed that comparable high repeatability of OCTA-CPD can be achieved in both research sites using the same device, scan protocol, and image analysis.