OBJECTIVE: To investigate the radial peripapillary capillary plexus vessel density (RPCP-VD) and peripapillary retinal nerve fiber layer thickness (pRNFLT) of systemic lupus erythematosus (SLE) and neuropsychiatric SLE patients (NPSLE) using disc optical coherence tomography angiography (OCTA) and investigate the association between these parameters and SLE disease activity index (SLEDAI-2K).
METHODS: A total of 64 \'right eyes (36 SLE patients, 28 healthy controls (HCs)) were included in this cross-sectional case-control study. Ten (27.7%) patients had neuropsychiatric involvement. RPCP-VD and pRNFLT of patients were evaluated in all peripapillary sectors. RPCP-VD and pRNFLT of NPSLE, non-NPSLE, and HCs were compared. The correlation between SLEDAI-2K and OCTA findings was evaluated.
RESULTS: SLE patients\' RPCP-VDs were significantly lower compared with the HCs except for two sectors (p < .005). There was not a significant difference in pRNFLT of SLE patients and HCs. There was not a correlation between SLEDAI-2K and RPCP-VD in any subsectors but there was a significantly negative correlation between pRNFLT in tempo-inferior and inferior-temporal sectors. When compared with non-NPSLE-patients, NPSLE patients had significantly lower inferior-hemi (p = .001), inferior-nasal VDs (p = .003), and peripapillary (p = .012), superior-hemi (p = .038), inferior-hemi (p = .026), inferior-nasal (p = .002) and inferior-temporal (p = .012) pRNFLTs. A negative correlation was found between NPSLE and pRNFLT.
CONCLUSIONS: SLE patients may have early subclinical vascular involvement leading to decreased RPCP-VD. A negative correlation between the SLEDAI-2K and pRNFLT in the temporal subsectors of all SLE patients may show an association between the disease activity and temporal pRNFL thinning. The presence of neuropsychiatric involvement may also be associated with decreased RPCP-VD and pRNFLT.

OBJECTIVE: To establish a normative database for vascular density (VD) of radial peripapillary capillary plexus (RPC) in healthy Caucasian subjects.
METHODS: 633 healthy Caucasian subjects underwent a complete ophthalmological examination, including slit-lamp biomicroscopy, best corrected visual acuity measurement with Early Treatment Diabetic Retinopathy Study charts, intraocular pressure measurement, fundus examination, and macular and optic nerve head (ONH) structural optical coherence tomography (OCT). En-face 4.5 × 4.5 mm OCT angiography scans of the RPC plexus were recorded and VD values, automatically provided by the AngioAnalytics™ software, noted. We statistically estimated the impact of age and gender on RPC VD values using a linear mixed model.
RESULTS: 560 subjects fully met inclusion criteria and, according to age, were stratified into 5 groups: 18-50 years (77), 51-60 years (160), 61-70 years (110), 71-80 years (132), and ≥ 81 years (81). Overall, mean RPC VD of the whole en-face image was 53.03 ± 4.27%. Age was significantly related to RPC VD values of whole en-face image (r = -0.454; p < 0.0001), which decreased with aging. The linear mixed model disclosed that age has a statistically significant effect on RPC VD values in whole en-face image (p = 0.0006). As age increases, RPC VD values decrease by 0.12 per year. Conversely, no significant gender-related differences were found in terms of RPC VD values of whole en-face image and each parapapillary quadrant analyzing all age group.
CONCLUSIONS: Results show that RPC VD values in healthy Caucasian subjects decrease with aging. These data may be used to create a reference normative database useful for clinical use.
CONCLUSIONS: What is known Radial peripapillary capillary (RPC) plexus, consisting of long parallel capillaries with rare bifurcations and anastomosis and extending straight along the course of the retinal nerve fiber layer to the posterior pole, may be affected early in some optic nerve head (ONH) and retinal diseases. What is new This study reports RPC vascular density (VD) values, automatically measured on optical coherence tomography angiography, in healthy Caucasian subjects, demonstrating that age is negatively related to RPC VD values. Results show that RPC VD values in healthy Caucasian subjects decrease with aging. These data may be used to create a reference normative database useful for clinical use.

UNASSIGNED: To compare radial peripapillary capillary (RPC) vascular plexus parameters and peripapillary retinal nerve fiber layer (pRNFL) thickness between Early-Treated Adults with Phenylketonuria (ETPKU) and controls.
UNASSIGNED: This observational study was a monocentric, case control study including 36 eyes of 36 participants. Among these, 18 were early-treated PKU (ETPKU) and 18 were controls. A SD-OCTA (XR Avanti AngioVue OCTA; Optovue Inc., Fremont, CA) was employed to assess the OCT and OCTA parameters of all the participants. The main outcome measures were the RPC vessels density (VD) %, and the pRNFL thickness.
UNASSIGNED: The average pRNFL thickness was significantly reduced in ETPKU (110.78 ± 12.48 μm) compared to controls (113.22 ± 13.95 μm), p = 0.046. The mean VD% of the small vessels of the RPC plexus was 52.31 ± 2.2 in ETPKU and 50.71 ± 3.2 in controls (p = 0.049), while the VD% of all the radial peripapillary capillary plexus (RPCP) was 58.5 ± 2.2 in ETPKU and 55.08 ± 3.4 in controls (p < 0.001). By contrast, there were no differences in age, sex, and IOP between the two groups.
UNASSIGNED: Through structural OCT and OCTA, we observed thinning of the nerve fibers accompanied by an increase in perfusion of the RPC plexus. Thus, our conclusions suggest that OCTA may serve as a noninvasive method to identify novel retinal biomarkers in ETPKU.

OBJECTIVE: 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).
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.

BACKGROUND: Using OCT and OCTA imaging, we aimed to determine whether COVID-19 induces pathological changes in vascular and morphological structures in the pediatric retina.
METHODS: The current prospective, cross-sectional, observational clinical study included recovered pediatric patients with COVID-19 evaluated between May 2020 and June 2020. Retinal vascular (radial peripapillary, superficial, and deep capillary plexus vessel densities) and morphological (peripapillary retinal nerve fiber, ganglion cell layer, retinal, and choroidal thickness) in the optic disk and macula regions were quantitively assessed using OCT and OCTA. Data were compared between COVID-19 patients and age-matched controls.
RESULTS: The COVID-19 group included 32 eyes of 16 patients and the control group included 32 eyes of 16 cases. Fundus and biomicroscopic examinations revealed no signs of pathology in the COVID-19 group. Mean peripapillary retinal nerve fiber, ganglion cell layer, and choroidal thickness values were significantly greater in the COVID-19 group than in the control group (p<0.05). OCTA indicated that mean superficial and deep capillary plexus vessel densities, and choriocapillaris flow area values were significantly lower in the COVID-19 group than in the control group, whereas mean radial peripapillary capillary plexus vessel density values were significantly higher (p<0.05).
CONCLUSIONS: Even if fundus examination results appear normal in pediatric patients with COVID-19, vascular and morphological changes may be observed in the retina. Further studies with larger numbers of patients are needed to elucidate the clinical significance of vascular and morphological changes in this population.

OBJECTIVE: To investigate the vessel density (VD) of the radial peripapillary capillary (RPC) plexus in patients affected by preperimetric glaucoma (PPG), amnestic mild cognitive impairment (aMCI) and in a healthy control group using optical coherence tomography angiography (OCTA) in order to clarify the pathogenetic mechanisms of these neurodegenerative diseases.
METHODS: In this prospective study, we studied 54 eyes of 54 patients with PPG, 54 eyes of 54 patients with aMCI and 54 healthy controls. All subjects underwent structural spectral domain optical coherence tomography (SD)-OCT to assess the ganglion cell complex (GCC) and the retinal nerve fibre layer (RNFL). OCTA was used to evaluate the VD of the RPC in different regions (whole image, inside disc and peripapillary).
RESULTS: The PPG and aMCI groups showed a statistically significant reduction in SD-OCT and parameters with respect to controls (p < 0.001). No statistically significant difference was found in GCC and RNFL parameters between the two study groups (p > 0.05). At OCTA examination, PPG and aMCI patients exhibited a statistically significant reduction in the VD of the RPC in whole image, inside and peripapillary regions compared to healthy controls (p < 0.001). When comparing the two study groups, the OCTA parameters were significantly impaired in PPG with respect to aMCI patients. Significant correlations were found between structural OCT and OCTA parameters in PPG and aMCI groups (p < 0.05).
CONCLUSIONS: RPC vessel density could represent a helpful and sensible biomarker to identify early retinal microvascular changes in PPG and MCI in order to better understand the vascular pathophysiological mechanisms involved in these neurodegenerative diseases.

The aim of this study was to evaluate the macular and peri-papillary blood vessel density following uncomplicated phacoemulsification in diabetics using optical coherence tomography angiography (OCT-A).
An observational case-control study was conducted on 60 patients eligible for phacoemulsification, divided equally into diabetic and control groups. Both study groups were matching in sex, age, and axial length. We excluded diabetic patients of any form of macular edema or treatment history for macular edema. All study participants were subjected to preoperative OCT and OCT-A, which was repeated for all study population 1 month postoperatively.
We had a mean age of 54.5 ± 6.34 years in the non-diabetic group and 57.2 ± 4.09 years in the diabetic group (P = 0.06). There was a significant increase in the mean value of the macular blood vessels density in the nasal area in both study groups (P = 0.047 in non-diabetic group, P = 0.002 in the diabetic group). The percentage of the radial peripapillary capillary plexus vessel density (RPCP VD) change was non-significant on comparing the results for the diabetic group (mean preoperative value = 52.8 ± 4.47, postoperative = 52.0 ± 4.59, P = 0.204, Δ is the preoperative-postoperative value = 0.8), and also was non-significant for the non-diabetic group (mean preoperative value = 50.9 ± 4.89, postoperative = 52.1 ± 4.89, P = 0. 0.090, Δ = -1.3). On comparing the results of the diabetic and nondiabetic groups, the RPCP VD Δ was significantly different (P = 0.034).
Uncomplicated phacoemulsification results in increase of the nasal macular blood vessel density in the normal population and in diabetic patients without retinopathy.

OBJECTIVE: To compare radial peripapillary capillary (RPC) plexus vascular parameters and retinal nerve fiber layer (RNFL) thickness between those with Parkinson\'s disease (PD) and controls.
METHODS: Prospective, cross-sectional study.
METHODS: A total of 151 eyes of 81 PD participants and 514 eyes of 266 controls.
METHODS: Participants underwent OCT angiography (OCTA) imaging using the Zeiss Cirrus HD-5000 AngioPlex (Carl Zeiss AG). Capillary perfusion density (CPD) and capillary flux index (CFI) were assessed using a 4.5 × 4.5-mm peripapillary scan, and RNFL thickness was assessed using a 200 × 200-μm optic nerve cube OCT scan. Hoehn and Yahr clinical staging for PD was determined by an experienced movement disorders specialist. Generalized estimating equations adjusted for age and sex were used for analysis.
METHODS: Differences in RNFL thickness, CPD, and CFI as assessed using multivariable generalized estimating equations between individuals with PD and controls.
RESULTS: After adjustment for age and sex, average CPD (0.446% ± 0.018% vs. 0.439% ± 0.017%, P < 0.001) and CFI (0.434 ± 0.031 vs. 0.426 ± 0.036, P = 0.008) were significantly higher in PD eyes. Average RNFL thickness was similar between groups (PD 89.71 ± 10.45 μm vs. control 88.20 ± 10.33 μm, P = 0.19). Significant correlations between Hoehn and Yahr stage and OCTA parameters were not observed. The OCTA parameters were not significantly different between eyes of the same patient.
CONCLUSIONS: Increased peripapillary microvascular density and flux were detected in a large cohort of individuals with PD compared with controls after adjusting for age and sex; however, RNFL thickness was similar between groups. Peripapillary OCTA parameters may not correlate with the severity of PD. OCTA may serve as a noninvasive method to identify novel biomarkers for the early diagnosis of PD; as such, this methodology deserves further investigation.

BACKGROUND: The aim of the study was to investigate whether retinal neurovascular structural impairment in children and adolescents with type 1 diabetes mellitus (T1D) without clinical signs of diabetic retinopathy (DR) could be detected early via optical coherence tomography (OCT) and OCT angiography (OCTA).
METHODS: In the current prospective, cross-sectional, observational clinical study children and adolescents with T1D without DR were evaluated between December 2018 and May 2019. Retinal neurovascular structures in the macular and optic disc regions were examined in detail and quantitatively assessed using OCT and OCTA. Data from subjects with T1D were compared with data from healthy controls. Whether retinal neurovascular structural changes were significantly associated with puberty stage, diabetes duration, and HbA1c level was also investigated.
RESULTS: The T1D group included 110 eyes and the control group included 84 eyes. In the T1D group the mean inside disc vessel density (VD) was significantly lower than that of the control group (p < 0.001), as was the mean superior temporal disc VD (p < 0.043). Puberty stage was significantly associated with retinal thickness, parafoveal superficial capillary plexus VD, and peripapillary retinal nerve fiber layer thickness (p < 0.05). Diabetes duration and HbA1c level was significantly correlated with retinal layer thickness, foveal avascular zone diameter, and superficial and deep capillary plexus VDs.
CONCLUSIONS: In children and adolescents with T1D without clinical signs of DR, the VD of the disc region is affected earlier than the macular region. In these patients, early neurovascular impairment can be detected non-invasively via OCT and OCTA.

OBJECTIVE: To investigate the retinal microvasculature in patients with surgically induced hypoparathyroidism who have no clinical evidence of retinopathy and to compare these data with those of healthy control subjects.
METHODS: Forty patients with a confirmed diagnosis of permanent hypoparathyroidism and no clinical evidence of retinopathy and 37 age- and sex-matched healthy control subjects were included in the study. After complete ophthalmological examination, all patients underwent optical coherence tomography angiography measurement (Optovue Inc., Fremont, California, USA) to assess the foveal avascular zone (FAZ) area; FAZ perimeter; acircularity index of FAZ; foveal density-300; radial peripapillary capillary plexus (RPCP) vessel density; superficial, middle and deep capillary plexus vessel densities (SCP, MCP and DCP). The data from the right eyes of all participants were used for statistical analysis.
RESULTS: The SCP and MCP vessel densities were significantly lower, and the RPCP whole image and peripapillary vessel densities were significantly higher than those in healthy control subjects (p < 0.05 for all). The DCP vessel densities of patients with surgically induced hypoparathyroidism were not significantly different from those of healthy control subjects (p > 0.05 for all). No significant difference was found in the FAZ area, FAZ perimeter, acircularity index of FAZ, foveal density-300 measurements between patients and controls (p > 0.05 for all).
CONCLUSIONS: Reduced retinal vessel density in patients with surgically induced hypoparathyroidism supports the hypothesis that parathyroid hormone is associated with regulation of vascular homeostasis, including macular microcirculation. Increased perfusion in the peripapillary area may suggest an early subclinic effect of hypoparathyroidism.