Analyses of the ratio of ganglion cell-inner plexiform layer thickness to vessel density according to age in healthy eyes.

PURPOSE: To identify how the inner retinal layer and microvasculature change with age by analyzing the relationships of ganglion cell-inner plexiform layer (GC-IPL) thickness, vessel density (VD), and the ratio of these measurements with age in healthy eyes. METHODS: Participants were divided into five groups according to age. The GC-IPL thickness, VD, and GC-IPL/VD ratio were compared among the groups. Linear regression analyses were performed to identify relationships of GC-IPL/VD ratio with age. RESULTS: The average GC-IPL thicknesses were 84.84 ± 5.28, 84.22 ± 5.30, 85.20 ± 6.29, 83.29 ± 7.06, and 82.26 ± 5.62 µm in the 20s, 30s, 40s, 50s, and 60s age groups, respectively. The VDs were 20.94 ± 1.50, 21.06 ± 1.50, 20.99 ± 1.03, 20.71 ± 0.93, and 19.74 ± 1.73 mm-1 in the 20s, 30s, 40s, 50s, and 60s age groups, respectively. The GC-IPL/VD ratio was 4.05, 4.00, 4.06, 4.02, and 4.17 in each group, respectively, and the ratio of the 60s age group was significantly higher than that of other groups. In linear regression analyses, the GC-IPL/VD ratio was significantly associated with age in the participants aged ≥ 50 years (B = 0.014, P = 0.013), whereas it was not in the participants aged < 50 years (B = 0.003, P = 0.434). CONCLUSIONS: GC-IPL thickness and macular VD showed a tendency to decrease beginning in the 50s age group and the GC-IPL/VD ratio was significantly increased in the 60s age group. Additionally, the GC-IPL/VD ratio was positively associated with age in subjects aged ≥ 50 years, which implies a more pronounced decline over time in VD rather than GC-IPL thickness.

Synthesis and Corrosion Inhibition Potential of Cerium/Tetraethylenepentamine Dithiocarbamate Complex on AA2024-T3 in 3.5% NaCl.

In this work, a cerium/tetraethylenepentamine dithiocarbamate complex was synthesized and evaluated for the corrosion inhibition capability on an AA2024-T3 Al alloy in a 3.5% NaCl medium. The synthesized compounds were characterized via spectroscopic techniques. The corrosion inhibition behaviour of the complex was elucidated by electrochemical measurements and surface analysis techniques. Based on electrochemical test results, the corrosion inhibition efficiency of the complex increases with the immersion time of aluminium alloy in the test solution. The corrosion inhibition reaches 96.80% when the aluminium is immersed in a 3.5% NaCl solution containing a corrosion inhibitor for 120 h. The potentiodynamic polarization test results show that the complex acts as a mixed-type corrosion inhibitor and the passive range is widened. The surface analysis methods reveal that the corrosion inhibition ability of the complex originated from the formation of a protective layer on the Al surface. This film is created from the physisorption and chemisorption of cerium ions and organic parts simultaneously released from the complex molecules.

Effect of Weiss ring on peripapillary retinal nerve fiber layer thickness measurements using SD-OCT.

Spectral-domain optical coherence tomography (SD-OCT) must accurately identify and measure the peripapillary retinal nerve fiber layer (pRNFL) thickness to improve the repeatability and reproducibility, and reduce measurement errors. Because Weiss ring can be located in front of the optic disc, we hypothesized that it may affect pRNFL thickness measurements obtained using SD-OCT. We retrospectively reviewed the medical records of patients with (group W) and without (group N) Weiss ring, observed on OCT fundus image and an RNFL map devised using SD-OCT. Optic disc cube scans (200 × 200) were obtained to measure pRNFL thicknesses (superior, temporal, inferior, nasal, and average) at two consecutive visits. Pearson's correlation coefficient (r), intraclass correlation coefficient (ICC), and coefficient of variation (CV) were calculated. The r and ICC values for the pRNFL thickness measurements at the two visits were lower for group W compared to group N, but statistical significance was reached only for inferior pRNFL thickness. In addition, CV values were greater for group W compared to group N, but the differences were significant only for inferior and average pRNFL thickness measurements (p < 0.001 and p = 0.004, respectively). Weiss ring located near the optic disc can affect pRNFL thickness measurements and repeatability thereof, especially the inferior quadrant and average values. Therefore, it is important to identify the presence of Weiss ring when analyzing pRNFL thickness values.

Retinal nerve fibre layer/ganglion cell-inner plexiform layer thickness ratio in patients with systemic hypertension.

PURPOSE: Acute and chronic hypertension may have different pathophysiological mechanisms in the retina. Here, we compared the retinal nerve fibre layer (RNFL)/ganglion cell-inner plexiform layer (GC-IPL) thickness ratios of patients with 'relieved' severe hypertensive retinopathy (relieved HTNR) and chronic hypertension without retinopathy (chronic HTN) to those of normal controls. METHODS: We performed cross-sectional study. The eyes were divided into the following groups: normal controls (Group A, age ≥50 years; Group D, age <50 years); chronic HTN (Group B, <10 years of HTN; TNHT; Group C, ≥10 years of HTN); and relieved HTNR (previously diagnosed with grade IV HTNR and relieved retinopathy for >1 year; Group E), and the RNFL/GC-IPL thickness ratio was compared among Groups A-C and between Groups D and E. RESULTS: A total of 379 eyes were included in this study. Groups A-E consisted of 145, 59, 63, 60 and 52 eyes, respectively. The RNFL/GC-IPL thickness ratios were 1.161 ± 0.093, 1.158 ± 0.082 and 1.162 ± 0.089 in groups A-C, respectively, and did not showed a statistically difference (p = 0.966). The RNFL/GC-IPL thickness ratio of groups D and E were 1.169 ± 0.080 and 1.221 ± 0.080, respectively, and showed a statistically difference (p = 0.001). CONCLUSIONS: The RNFL/GC-IPL thickness ratios of the chronic HTN group did not show a difference compared with the normal controls. However, relieved HTNR patients showed a higher ratio than the normal controls. Physicians should be aware that acute hypertensive injury could affect the RNFL/GC-IPL thickness ratio.

Long-term repeatability of peripapillary optical coherence tomography angiography measurements in healthy eyes.

This is a prospective observational study to establish the short- and long-term repeatability of measurements of peripapillary optical coherence tomography angiography (OCTA) parameters in healthy eyes and identify factors affecting long-term repeatability. We enrolled 84 healthy eyes. Participants with a history of any ophthalmic disease (except high myopia) or intraocular surgery were excluded from the study. An experienced examiner performed OCTA using disc-centered 6 × 6 mm scans. All examinations were conducted twice at 5-min intervals at the initial visit and repeated at least 6 months later. For short-term repeatability, the coefficient of variation (CV) was 2.94-4.22% and the intraclass correlation coefficient (ICC) was 0.840-0.934. For long-term repeatability, the CV was 2.73-3.84% and the ICC was 0.737-0.934. Multivariate analyses showed that the axial length (AL) (B = 0.970; p = 0.002) and mean signal strength (SS) (B = - 2.028; p < 0.001) significantly affected long-term repeatability. Measurements of peripapillary OCTA parameters exhibited excellent short-term and good long-term repeatability in healthy individuals. The mean SS and AL affected long-term repeatability and should be considered while interpreting peripapillary OCTA images.

Bilateral retinal pigment epithelial tears in acute central serous chorioretinopathy without bullous retinal detachment: A case report.

RATIONALE: Several reports have described retinal pigment epithelial (RPE) tears in central serous chorioretinopathy (CSC). However, there have been no reports of spontaneously large RPE tears in acute CSC without bullous retinal detachment (RD). Herein, we report and provide sequential images of a case of bilateral spontaneous large RPE tears in patient with acute CSC without bullous RD. PATIENT CONCERNS: An 88-year-old female patient was admitted with impaired vision in both eyes, which began 10 days prior. The visual acuity was 0.4 and 0.5 in the right and left eye, respectively. She had started taking oral steroids 2 weeks prior for polymyalgia. DIAGNOSIS: Ophthalmologic examinations, including fundus photography, optical coherence tomography, and fluorescence angiography, were performed, and she was diagnosed with steroid-induced acute CSC in both eyes with large pigment epithelial detachment (PED) of approximately 4-disc diameter. Discontinuation of steroids and follow-up ophthalmic examinations were performed. However, a spontaneous large RPE tear occurred in the right eye. INTERVENTIONS: We performed follow-ups more frequently and CSC treatment such as laser photocoagulation, photodynamic therapy, and anti-vascular endothelial growth factor injections were not performed. OUTCOMES: Nine months later, a spontaneous large RPE tear occurred sequentially in the left eye. Her final visual acuity was 0.3 and 0.15 in the right and left eye, respectively. LESSONS: Patients may spontaneously develop large RPE tears in both eyes, despite no treatment for acute CSC with non-bullous RD. Large PED and old age may affect this. Therefore, for a CSC patient with a large PED and advanced age, attention must be paid when determining treatment.

Effect of axial length on peripapillary microvasculature: An optical coherence tomography angiography study.

OBJECTIVE: To investigate the effects of axial length (AL) on the peripapillary microvascular density acquired from optical coherence tomography angiography (OCTA). METHODS: Retrospective observational study. A total of 111 eyes from 111 normal healthy subjects were examined. The subjects were divided into three groups according to the AL: Group 1 (AL: < 24.0 mm; 35 eyes), Group 2 (AL: 24.0-25.99 mm; 37 eyes), and Group 3 (AL: ≥ 26 mm; 39 eyes). Peripapillary OCTA images were acquired using 6× 6 mm angiography scans, and vessel density (VD) and perfusion density (PD) of the superficial capillary plexus were calculated automatically. VD and PD were compared among the three groups according to the distance from the optic disc (inner and outer rings). Linear regression analyses were also performed to identify clinical factors associated with average VD. RESULTS: The average ALs of Groups 1-3 were 23.33± 0.57, 25.05± 0.60, and 27.42± 0.82, respectively. Average VD (P = 0.009) and PD (P = 0.029) in the inner ring increased with increasing AL. However, average VD (P < 0.001) and PD (P < 0.001) in the outer ring decreased with AL increased; the same trends were found for the full areas (VD, p<0.001; PD, p = 0.001). Average VDs in the inner and outer rings were not associated (P = 0.938). CONCLUSIONS: Peripapillary VD and PD were significantly associated with AL. Depending on the distance from the disc, peripapillary VDs and PDs of the inner and outer rings were differentially affected by AL. Physicians should therefore consider the effects of AL in the analyses of peripapillary microvasculature.

Spent Coffee Grounds as Eco-Friendly Additives for Aluminum-Air Batteries.

A new approach to the recycling of spent coffee grounds is described in which lignin, a chemical component of spent coffee, is used as an electrolyte additive in aluminum-air batteries. The effect of lignin on the performance of aluminum-air batteries has been investigated by weight loss measurement, galvanostatic discharge test, and electrochemical impedance spectroscopy (EIS). The corrosion inhibition efficiency is improved up to 37.3% and fuel efficiency up to 21.7% at 500 ppm of lignin molecules. The chemisorption of lignin molecules on the aluminum surface improves battery performance. Adsorption of lignin molecules onto the aluminum surface is driven by the electrostatic interaction between the lignin's hydroxyl group and the aluminum surface. The mechanism for the performance improvement is explained by the chemisorption behavior of lignin molecules. The adsorption behavior has been investigated by scanning electronic microscopy with energy-dispersive spectroscopy (SEM-EDS), laser scanning microscopy (LSM), atomic force microscopy (AFM), Freundlich adsorption isotherm, Fourier-transform infrared (FT-IR) spectroscopy, and the computational calculation of adsorption energies based on the density functional theory (DFT).

Wide-Field Swept-Source OCT Analysis of Interocular Symmetry of Choroidal Thickness in Subjects with Uncomplicated Pachychoroid.

BACKGROUND: We aimed to study the bilateral choroidal thickness (CT) symmetry and difference in uncomplicated pachychoroid subjects using wide-field swept-source optical coherence tomography (SS-OCT). METHODS: All subjects underwent a wide-field 16-mm one-line scan using SS-OCT. Bilateral CT was measured at, and compared among, the following 12 points: three points at 900-µm intervals from the nasal optic disc margin (nasal peripapillary area), one point at the subfovea, six points at 900-µm intervals from the fovea to the nasal and temporal areas (macular area), and two peripheral points 5400 and 8100 µm from the fovea (peripheral area). RESULTS: There were no statistically significant differences in CT between the right and left eyes in any area (all p > 0.05); they all showed significant positive correlations (all p < 0.01). However, the correlation coefficients (ρ) were smaller for the nasal peripapillary and peripheral areas compared to the macular area. CONCLUSIONS: The CTs in each region were bilaterally symmetrical in subjects with uncomplicated pachychoroid. However, interocular difference in CT increased from the center to the periphery, indicating that the anatomical variation of the nasal peripapillary and peripheral choroid was greater than that of the macula.

Effect of Systemic Hypertension on Peripapillary RNFL Thickness in Patients With Diabetes Without Diabetic Retinopathy.

Type 2 diabetes mellitus (T2DM) and hypertension (HTN) are both relatively common systemic diseases and cause damage to the retina, such as inner retina reduction and microvascular impairment. The purpose of this study was to identify peripapillary retinal nerve fiber layer (pRNFL) damage by diabetic neurodegeneration and the effects of HTN on the pRNFL thickness in patients with T2DM without clinical diabetic retinopathy. Subjects were divided into three groups: healthy control subjects (group 1), patients with T2DM (group 2), and patients with both diabetes and HTN (group 3). The pRNFL thickness was measured using optical coherence tomography and compared among each group. Linear regression analyses were performed to identify factors associated with pRNFL thickness. A total of 325 eyes were included: 143 eyes in the group 1, 126 eyes in group 2, and 56 eyes in group 3. The mean pRNFL thicknesses of each group were 96.1 ± 7.7, 94.4 ± 8.6, and 91.6 ± 9.6 µm, respectively (P = 0.003). In multivariate linear analyses, diabetes duration (ß = -0.236; P = 0.018) and HTN (ß = -3.766; P = 0.008) were significant factors affecting the pRNFL thickness in groups 2 and 3. Additionally, the HTN duration was significantly correlated with pRNFL thickness in group 3 (R 2 = 0.121; P = 0.008). In conclusion, patients with T2DM with HTN showed thinner pRNFL thickness than those with T2DM only. Additionally, the duration of HTN was significantly correlated with pRNFL thickness in patients with both diabetes and HTN.