Quantification of choroidal hyperreflective layer: A swept-source optical coherence tomography study.

PURPOSE: To investigate variation in reflectivity of choroidal layers in normal eyes. METHODS: From the swept-source optical coherence tomography database, we retrospectively included eyes with a normal fundus. Choroidal reflectivity was measured on the horizontal and vertical B-scan optical coherence tomography images. The optical barrier of the choroid was defined as the first hill in the middle of the reflectance graph from the retinal pigment epithelium-Bruch's membrane complex to the chorioscleral junction. RESULTS: The optical barrier of the choroid was identified in 91 eyes of 91 individuals. The amplitude of peak reflectivity of the optical barrier of the choroid at macular center (142.85 ± 15.04) was greater than those in superior (136.12 ± 14.08) or inferior macula (135.30 ± 16.13) (P = 0.028, P = 0.008, respectively). Latency between the peak of the retinal pigment epithelium-Bruch's membrane complex and the optical barrier of the choroid at macular center (48.11 ± 13.78 µm) was shorter than those in nasal macula (55.58 ± 19.21 µm) (P = 0.021). The amplitude of the peak reflectivity of the optical barrier of the choroid in the center negatively correlated with the latency between the retinal pigment epithelium-Bruch's membrane complex and the optical barrier of the choroid (P < 0.001). CONCLUSION: An optical barrier exists in the inner choroid of the normal eye. Its depth depends on the location within the macula. Further studies are mandatory to evaluate variations in the barrier in the eyes with chorioretinal disease.

A Comprehensive Analysis of the Influence of Temperature and Humidity on Dry Eye Disease.

PURPOSE: To investigate the effects of humidity and temperature on dry eye disease (DED). METHODS: A retrospective, clinic-based study was conducted on DED patients undergoing dry eye treatment. Patients were followed up at least twice, and symptoms and signs were evaluated using the Symptoms Assessment Questionnaire in Dry Eye (SANDE) score, tear secretion, tear film breakup time (TBUT), ocular staining score, and tear osmolarity. Mean humidity and temperature values for 1 week before ocular examinations were used as the environmental exposure level. The relationship between humidity and temperature, with DED clinical parameters was analyzed in single- and multi-environmental factor models. RESULTS: The study included 33 patients with a mean age of 53.9 ± 12.2 years. The low humidity group showed significantly higher SANDE scores (p = 0.023) and tear osmolarity (p = 0.008), and the low temperature group had higher SANDE scores (p = 0.004), ocular staining scores (p = 0.036), and tear osmolarity (p < 0.001). In the linear mixed model, single factor analysis showed that an increase in humidity resulted in decreased SANDE scores (p = 0.043), and an increase in temperature led to a decrease in SANDE score (p = 0.007), ocular staining score (p = 0.007), and tear osmolarity (p = 0.012). In the multifactor analysis, changes in humidity had no significant effect on dry eye parameters, but an increase in temperature was significantly correlated with decreased SANDE score (p = 0.026), ocular staining score (p = 0.024), and tear osmolarity (p = 0.002). CONCLUSIONS: Lower temperature led to aggravated symptoms and signs of DED and the effect of temperature on DED was more pronounced than humidity. Tear osmolarity was the most sensitive clinical parameter to be affected by climate factors in DED patients.

Comparison of Corneal Epithelial Wound Healing between Topical RCI001, Solcoseryl, and Polydeoxyribonucleotide in the Murine Ocular Alkali Burn Model.

PURPOSE: To compare the corneal epithelial wound healing effects of RCI001, Solcoseryl, and polydeoxyribonucleotide (PDRN) in a rat alkali burn model. METHODS: In 40 male Sprague-Dawley rats, we induced alkali burn using filter paper soaked in 0.2N sodium hydroxide. The rats were then treated with topical 0.5% RCI001, 1.0% RCI001, Solcoseryl, or PDRN twice a day for 2 weeks. Corneal epithelial integrity and epithelial healing rate were measured at day 0, 3, 5, 7, 10, and 14. Histologic and immunohistochemistry findings were also assessed. RESULTS: Both the 0.5% and 1.0% RCI001 groups showed significantly more epithelial healing compared to the control group at day 5, 7, 10, and 14 (each p < 0.05). No statistical difference was found between the 0.5% and 1.0% RCI001 groups. Neither the Solcoseryl nor the PDRN groups showed a significant difference from the control. RCI001 treatment resulted in significantly reduced stromal edema, and a trend towards less inflammatory cell infiltration. CONCLUSIONS: Topical application of RCI001 showed enhanced corneal epithelial wound healing in the murine corneal alkali burn model, presumably by suppressing inflammation. Meanwhile, Solcoseryl and PDRN did not show sufficient therapeutic effects compared to RCI001.

Bidirectional Dimples After Internal Limiting Membrane Peeling for a Macular Hole.

Purpose: To investigate microstructural changes and prognosis associated with retinal surface dimples after internal limiting membrane (ILM) peeling for macular holes (MHs). Methods: We analyzed swept-source optical coherence tomography (SS-OCT) images of patients who underwent surgery for idiopathic MHs. The inner retinal dimples on SS-OCT images were classified into three types: unidirectional, bidirectional, and complicated bidirectional dimples. Results: Dimples were found in 97.1% of the 69 eyes (69 patients) during a mean follow-up period of 14.0 ± 11.9 months after MH surgery. Of the eyes with dimples, 83.6% had bidirectional dimples. The proportion of eyes with dimples increased from 55.3% at 1 month postsurgery to 95.5% at 3 months and 97.9% at 6 months postsurgery. However, the proportion of eyes with complicated bidirectional dimples gradually increased from 1 month (29.8%) to 3 months (46.3%) and 6 months (64.6%) postsurgery. In the multivariable generalized estimating equation model, complicated bidirectional dimples occurred more frequently in eyes with shorter axial length (P = 0.039) and longer follow-up duration (≥6 months; at 6 months: P = 0.001; at 12 months: P = 0.009). Conclusions: Changes in retinal layers associated with retinal surface dimples after ILM peeling can occur at different retinal depths and over different time courses. These findings suggest the progression of dimple-associated remodeling of the underlying retinal layer. Translational Relevance: Various types of dimples can be used as surrogates to evaluate structural changes and outcomes of MH surgery.

Relationship between blood pressure levels and ischemic stroke, myocardial infarction, and mortality in very elderly patients taking antihypertensives: a nationwide population-based cohort study.

BACKGROUND: In the very elderly, "the lower the better" hypothesis has constantly been contradicted by randomized control trials and various cohort studies, but inconsistency in results led to unclear blood pressure treatment targets. This study aimed to assess the relationship between baseline blood pressure (BP) and ischemic stroke, myocardial infarction, and all-cause mortality in very elderly people treated for hypertension. METHODS: This large population-based retrospective cohort study was based on the national claims database of the Korean National Health Insurance System, which covers the entire Korean population. 374,250 participants aged ≥ 75 years taking antihypertensive agents were recruited, excluding patients with a history of previous ischemic stroke or myocardial infarction. RESULTS: Systolic BP (SBP) followed a J curve for ischemic stroke and a U curve for all-cause mortality, with nadir ranges of 120 to 129 mmHg and 140 to 149 mmHg, respectively. While increasing diastolic BP (DBP) generally resulted in higher HRs for ischemic stroke, HRs for myocardial infarction and all-cause mortality significantly increased only when DBP was ≥ 80 mmHg and ≥ 90 mmHg, respectively. The SBP/DBP combination analysis showed that even with SBP < 130 mmHg, higher DBP ≥ 90 mmHg had higher HRs for all three outcomes compared to the reference group (130 to 149 / < 80 mmHg). CONCLUSIONS: There were no further benefits or even harm below certain BP levels for ischemic stroke, myocardial infarction, and all-cause mortality in very elderly hypertensive patients.

Multiplexed Cassegrain Reflector Antenna for Simultaneous Generation of Three Orbital Angular Momentum (OAM) Modes.

A multiplexed Cassegrain reflector antenna with a 2 × 2 open-ended rectangular waveguide (OERW) matrix feed and an orbital angular momentum (OAM) mode mux is proposed for the simultaneous generation of three OAM modes (l = 0, ±1). The OAM mode mux (OMM) was designed using sequential combinations of quadrature hybrids, crossovers, and phase shifters to multiplex and demultiplex three OAM modes at the same time. The 2 × 2 OERW matrix feed and the OMM were separately measured and their performances were verified according to proposed theories. A near-field antenna measurement for a multiplexed Cassegrain reflector antenna was conducted to obtain the far-field magnitude and phase patterns around polar elevation angle θ and azimuthal angle ϕ, thus confirming that our antenna can produce three OAM modes simultaneously. We also measured the communication link characteristics of two identical multiplexed antennas. The measurement results show that the channel isolation of three OAM modes is more than 12.7 [dB] and 17 [dB] for fixed and compensated receiver positions, respectively, indicating that the proposed antenna system can be used for independent communication links with the same frequency and polarisation.

Study on the factors affecting inadequate vaccine coverage in children

No abstract available.