Reduced macular inner retinal thickness and microvascular density in the early stage of patients with dysthyroid optic neuropathy

Background The goal was to investigate changes of the inner intra-retinal layer thicknesses and retinal capillary density (RCD) around the macula in thyroid-associated ophthalmopathy (TAO) patients with or without dysthyroid optic neuropathy (DON). Methods Forty-four TAO patients including 23 non-DON and 21 DON patients, and 38 healthy participants were enrolled. Spectral domain optical coherence tomography equipped with Angiovue was used to obtain three-dimensional retinal thickness maps and microvascular images of the superficial and deep retinal capillary layers (SRCL and DRCL, respectively) around the macula. Quantitative analyses were performed using a custom automated algorithm. Results The thicknesses of the nerve fiber layer, ganglion cell layer + inner plexiform layer, and ganglion cell complex (GCC) as well as the RCDs in the SRCL and DRCL in both TAO groups were significantly decreased compared to the controls. In addition, the RCDs in DRCL of the DON group were further decreased compared to the non-DON group. GCC thickness in both TAO groups was positively correlated with the RCDs of the SRCL in the total annular zone and in the temporal, inferior, and nasal sectors. The areas under the receiver operating characteristic curves for the GCC thickness combined with the RCD were generally larger than those of each single indicator. Conclusions Thinned inner intra-retinal layers and decreased RCDs in the TAO patients without DON revealed that morphological changes might precede visual dysfunction. The composite index of the retinal structure and the microvascular density might be valuable in the diagnosing, monitoring, and intervention for early DON

Reduced Retinal Microvascular Density Related to Activity Status and Serum Antibodies in Patients with Graves' Ophthalmopathy

: To investigate changes in retinal capillary density (RCD) that occur in Graves' ophthalmopathy (GO) and explore their association with the clinical manifestations for GO. : A total of 125 participants (93 GO patients and 32 normal subjects) were enrolled. All participants underwent ophthalmology and endocrinology examinations. Retinal microvasculature was imaged by spectral domain optical coherence tomographic angiography (OCT-A). The RCDs in the superficial and deep retinal capillary plexuses (SRCP and DRCP) were quantified by the custom software from the OCT-A images, which were divided into total annular zones (TAZ) and four quadrants. Multiple linear regression analysis was used to explore the associations between RCD and the relevant factors. : Significant reduction was seen in the TAZ zone in SRCP and DRCP of GO group ( < .05) when compared to the healthy subjects; significant differences remained after adjustment of vascular relevant factors. According to the univariate analysis, the relevant factors of higher IOP, larger proptosis, higher clinical activity scoring (CAS), thyroid stimulating hormone-receptor autoantibodies (TRAb), and I therapy were significantly associated with decreased RCDs in GO patients ( < .05). Multivariate linear regression analysis showed that CAS and TRAb were the most important relevant factors for decreased RCDs. : The RCD of GO patients was significantly decreased compared to the healthy controls. The activity status and serum antibodies associated with GO were the relevant factors for reduced RCD

Tzumin A and B, two new lignan derivatives from the barks of <i>Sassafras tzumu</i>

<p>Two new lignan compounds, 5′-allyl-2,2′-dihydroxy-[1,1′-biphenyl]-5-carboxylic acid (<b>1</b>) and 4,4′-diallyl-[1,1′-biphenyl]-2,2′-diol (<b>2</b>), together with four known compounds (<b>3–6</b>), were isolated from the barks of <i>Sassafras tzumu</i>. The new compounds were determined by NMR (¹H and ¹³C NMR, HSQC, HMBC, ¹H-¹H COSY, NOESY/ROESY), and MS analysis. Compounds <b>1–3</b> showed potent AChE inhibitory activities, with IC₅₀ values of 2.00, 1.81 and 1.91 μM, respectively.</p

Unique changes in the retinal microvasculature reveal subclinical retinal impairment in patients with systemic lupus erythematosus

To determine the changes of the microvasculature and microstructure in the inner intra-retinal layers in systemic lupus erythematosus (SLE) patients without lupus retinopathy (LR). Thirty-two SLE patients (58 eyes) without LR (NLR), 14 patients (22 eyes) with LR and 50 healthy subjects (50 eyes) were enrolled. Spectral domain optical coherence tomography equipped with Angiovue was used to obtain three-dimensional retinal thickness maps and microvascular images of the superficial and deep retinal capillary plexuses (SRCP/DRCP) around the macula. Quantitative analyses were performed using a custom automated algorithm. Disease activity of patients was assessed using the SLE disease activity index (SLEDAI). Retinal capillary skeleton density of the SRCP in SLE patients without LR was significantly lower than the controls in almost all regions, which further decreased in the LR group (P  .05). The inner retina in the LR group was significantly thinner than the controls in most regions, though there were only a few regions that were different between the NLR and the control groups (P < .05). There were significant differences of the SLEDAI scores between the two SLE groups. Significantly lower density in SRCP and regional thinning in inner retina were observed in the SLE patients without clinical fundus changes. OCT equipped with Angiovue might be useful in evaluating the microvascular and microstructural disorders of the inner retinal layers in SLE patients, which may contribute a quantitative approach to the early diagnosis and progression of LR. •Retinal microvasculature and microstructure were observed in SLE patients with and without lupus retinopathy.•General SRCP density decreasing and regional inner-retinal thinning were detected in SLE patients without lupus retinopathy.•OCT equipped with Angio may contribute a quantitative approach to the early diagnosis and progression of lupus retinopathy

Characteristics of Retinal Structural and Microvascular Alterations in Early Type 2 Diabetic Patients

To investigate early retinal structural and microvascular changes in patients with type 2 diabetes mellitus (DM) and to analyze relationships among the retinal structure, microvasculature, and choroid. Seventy-seven patients with type 2 DM (40 with no diabetic retinopathy [DR], 37 with nonproliferative diabetic retinopathy [NPDR]), and 34 control subjects were enrolled. Spectral-domain optical coherence tomography, operating in radial 18-line mode, obtained macular images of the eight intraretinal layers and the choroid. The same system was equipped with Angiovue to obtain angiography images of the whole, superficial, and deep retinal capillary layers (WRCL, SRCL, and DRCL) in a 3-mm-diameter area around the macula. Algorithms quantified the thicknesses of the intraretinal layers and choroid as well as fractal dimensions (Dbox values) of the retinal capillary layers. Pearson's correlation was used to analyze the relationships. The choroidal thickness was significantly decreased in all the regions of the DM patients with no DR (P < 0.05). Compared to controls, the Dbox values of the SRCL and DRCL were significantly decreased in diabetic patients with no DR; however, only the nerve fiber layer in this group was slightly thinner than in the controls (P < 0.05). In the two diabetic groups, there was a weak correlation between the ganglion cell complex thickness and the SRCL (P < 0.05). In DM, changes of retinal microvasculature might occur earlier than changes in retinal structure. Thinning of the choroid may be the earliest sign in the diabetic patients with no clinical DR

Associated risk factors in the early stage of Chick for diabetic retinopathy

Background: To investigate the retinal capillary density (RCD) of the macula using optical coherence tomography angiography (OCT-A) in type 2 diabetic patients and to further determine the association with risk factors. Methods: A total of 212 eyes from 212 subjects were recruited; subjects included diabetics with no retinopathy (NDR, n = 90 eyes), diabetics with mild retinopathy DR (MDR, n = 36 eyes), and healthy participants (Control, n = 86 eyes). All participants underwent OCT-A scanning. RCD was quantified by superficial and deep retinal capillary layers (SRCL and DRCL) from OCT-A images. Results: RCD in SRCL and DRCL was lower in NDR (P 55y, HbA1c > 7% had significantly reduced DRCL (P 8.2 mmol/L had significantly reduced SRCL and DRCL when compared to the other group of diabetics. Conclusions: Risk factors including older age, higher level of HbA1c, LDL-C and BUN, were associated with lower RCDs found in type 2 diabetic patients with and without mild DR by OCT-A. The impairment of retinal capillary by OCT-A may play a key role in the early monitoring of management in diabetes

Relationships among retinal/choroidal thickness, retinal microvascular network and visual field in high myopia

Purpose To determine the relationships among retinal/choroidal thickness, retinal microvascular network and visual field in high myopia. Methods This cross‐sectional study included a total of 62 subjects, comprising 31 eyes with high myopia and 31 eyes with emmetropia or low myopia. Optical coherence tomography was used to quantify the thickness of ganglion cell complex (GCC), inner nuclear layer and outer plexiform layer (INOPL), outer retinal layer (ORL) and choroid layer (ChL). Optical coherence tomography angiography was used to quantify the superficial vessel density (SVD) and deep vessel density (DVD). Retinal light sensitivity (RLS) was measured by microperimetry‐1 (MP1). The inner ring (1–1.75 mm), the outer ring (1.75–2.5 mm) and the whole ring (1–2.5 mm) around the macula were analysed and compared between the two groups. Pearson correlation analysis was performed to analyse the relationship among them. Results In the highly myopic group, the thinning of retinal/choroidal thickness and the decrease in retinal vessel density and RLS were found when compared to the emmetropia or low myopia (p  0.05), but DVD showed a negative correlation with ORL (r = −0.474, p = 0.007). Conclusion Early visual field defects in highly myopic eyes may be influenced by the ORL loss and defect of choroidal circulation. The deep retinal microvascular network may have a compensatory action in the hypoxic setting of high myopia

Interlayer vibrational modes in few-quintuple-layer Bi2Te3 and Bi2Se3 two-dimensional crystals : raman spectroscopy and first-principles studies

Layered materials, such as graphite/graphene, boron nitride, transition metal dichalcogenides, represent materials in which reduced size, dimensionality, and symmetry play critical roles in their physical properties. Here, we report on a comprehensive investigation of the phonon properties in the topological insulator Bi2Te3 and Bi2Se3 two-dimensional (2D) crystals, with the combination of Raman spectroscopy, first-principles calculations, and group theory analysis. Low frequency (<30cm−1) interlayer vibrational modes are revealed in few-quintuple-layer (QL) Bi2Te3/Bi2Se3 2D crystals, which are absent in the bulk crystal as a result of different symmetries. The experimentally observed interlayer shear and breathing mode frequencies both show blueshifts, with decreasing thickness in few-QL Bi2Te3 (down to 2QL) and Bi2Se3 (down to 1QL), in agreement with first-principles calculations and a linear chain model, from which the interlayer coupling force constants can be estimated. Besides, an intense ultralow (<12cm−1) frequency peak is observed in 2–4QL Bi2Te3, which is tentatively attributed to a substrate-induced interface mode supported by a linear chain model analysis. The high frequency Raman peaks exhibit frequency shifts and broadening from 3D to 2D as a result of the phonon confinement effect. Our studies shed light on a general understanding of the influence of dimensionality and crystal symmetry on the phonon properties in layered materials.ASTAR (Agency for Sci., Tech. and Research, S’pore)Published versio

Deep perifoveal vessel density as an indicator of capillary loss in high myopia

This study investigates the macular vasculature of both vascular layers in different degrees of myopia by optical coherence tomography angiography (OCTA). One hundred and forty-five eyes of 145 healthy subjects with spherical equivalents (SE) ranging from +0.50 to -16.50 dioptres were divided into three groups. The foveal avascular zone (FAZ) area and vessel density (VD) of OCTA images were compared. Compared with other groups, high myopia had a larger FAZ and less perifoveal VD in both layers and less deep total VD. Compared with other myopia, high myopia had less total VD in the superficial layer and parafoveal VD in the deep layer. Between emmetropia and low myopia, there was a difference only in the deep parafoveal VD. Except for the parafoveal VD in both layers and the superficial total VD, there were significant correlations of the FAZ with axial length (AL) and SE as well as VD. The deep perifoveal VD was most associated with high myopia. An increased FAZ and decreased VD in both layers were correlated with AL elongation. The decreasing deep perifoveal VD was most associated with high myopia. OCTA may provide additional information regarding the progression of pathologies in high myopia