Retinal and Conjunctival Vessels in the Diagnosis and Assessment of Behcet's Disease: A New Approach.

BACKGROUND AND OBJECTIVE: The study aimed to investigate the alterations of retinal and conjunctival vessels in patients with Behcet's disease (BD). PATIENTS AND METHODS: In this case-control study, 17 patients (34 eyes) diagnosed with BD and 17 healthy volunteers (34 eyes) matched by age, sex, blood pressure, and intraocular pressure were recruited. Optical coherence tomography angiography examinations were performed to calculate the vessel density of the retina and conjunctiva according to different sizes of vessels and different zones divided by three segmentation methods of the retina: hemispheric segmentation, Early Treatment Diabetic Retinopathy Study, and central annulus segmentation. RESULTS: The vessel densities of the superficial macrovascular (P = 0.050), superficial microvascular (P < 0.001), superficial total microvascular (P < 0.001), deep total microvascular (P < 0.001), and deep total microvascular (P < 0.001) were significantly lower in the BD group. The conjunctival vessel density was significantly higher in the BD group (P < 0.001). The receiver operating characteristic curve analysis showed that the area under the curve of vessel density of the superior right (0.993, 95% CI 0.980-1) and right zones (0.996, 95% CI 0.987-1) were the largest in the superficial and deep retina, respectively. Otherwise, the area under the curve of conjunctival vessel density was 0.728 (95% CI 0.607-0.848). CONCLUSIONS: In patients with BD, retinal vessel density decreases, while conjunctival vessel density increases. Optical coherence tomography angiography provides a new noninvasive and quantitative assessment for retinal and conjunctival vessels. [Ophthalmic Surg Lasers Imaging Retina 2024;55:13-21.].

Retinal microvascular and microstructural alterations in the diagnosis of dermatomyositis: a new approach.

Purpose: To study the relationship between fundus alterations, including retinal thickness and microvascular changes, and dermatomyositis (DM) using optical coherence tomography angiography (OCTA). Methods: A total of 16 patients with DM (32 eyes) and 16 healthy controls (HCs; 32 eyes) participated in this study. Based on the Early Treatment Diabetic Retinopathy Study subzones, OCTA fundus data were divided into different layers and regions for comparison. Results: The full retinal thickness (RT) in the inner nasal (IN), outer nasal (ON), inner inferior (II), and outer inferior (OI) regions of patients with DM was significantly lower than that of HCs (P < 0.001). The inner layer RT was also significantly lower in the IN, ON, II, and OI regions in patients with DM (P < 0.001). The outer layer RT was lower only in the II region in patients with DM compared to HCs (P < 0.001). The full RT of the II region was more sensitive to the pathological changes of disease since its ROC curve had an AUC of 0.9028, 95% CI: 0.8159-0.9898. Meanwhile, the superficial vessel density (SVD) of patients with DM was significantly lower in the IN, ON, II, and OI regions compared to HCs (P < 0.001). The AUC for region II was 0.9634 (95% CI: 0.9034-1.0), which indicated good diagnostic sensitivity. Conclusion: Optical coherence tomography angiography can be used to evaluate relevant ocular lesions and monitor disease progression in patients with DM and interstitial lung disease.

The Function of Retinal Thickness and Microvascular Alterations in the Diagnosis of Systemic Sclerosis.

In this study, we aim to investigate retinal thickness (RT) and superficial vascular density (SVD) differences between patients with systemic sclerosis (SSc) and healthy controls (HCs) by optical coherence tomography angiography (OCTA). Sixteen patients with a definitive SSc diagnosis without clinical signs of retinopathy and 16 normal control subjects were recruited. All individuals underwent OCTA scanning to assess macular RT and SVD. We divided each image into nine subregions as the early treatment diabetic retinopathy study (ETDRS). Visual acuity (VA) was considerably different between patients with SSc (32 eyes) and control subjects (32 eyes) (p < 0.001). Compared to the control group, individuals with SSc had decreased inner RT in inner superior, outer superior, outer temporal, inner temporal, center, and inner nasal regions (p < 0.05). Outer RT was decreased in the outer and inner temporal regions, and full RT was decreased in the regions of outer superior, inner superior, inner temporal, and outer temporal, in comparison to the control group (p < 0.05). Patients with SSc had significant reduction of SVD in the inner and outer of both superior and temporal, besides outer nasal regions than controls. (p < 0.05). Moreover, SVD was significantly associated with the outer temporal region of patients suffering from SSc (p < 0.05). Diagnostic Sensitivity of RT and SVD of Inner Superior Regions in SSc, as indicated by areas under curves of the Receiver Operating Characteristic (ROC), were 0.874 (95% CI: 0.786-0.962) and 0.827 (95% CI: 0.704-0.950), respectively. In conclusion, VA may be affected by RT variations inside the macula in patients with SSc. Measuring RT with OCTA could be a useful predictor of early diagnosis.

A plasmonic refractive index sensor with an ultrabroad dynamic sensing range.

Refractive index sensors based on surface plasmon resonance (SPR) promise to deliver high sensitivities. However, these sensitivities depend on the derivative of the monitored SPR parameters near resonance, so this dependency leads to a relatively narrow detection range for refractive index changes. Herein, we introduce an idea to improve the detection range refractive index through a high-contrast-index curved waveguide surrounded with an outer gold ring. The proposed detection technique, based on the output power measurement of the curved waveguide, offers a linear response over an ultrabroad range of the refractive index for a surrounding medium from n = 1 to 2.36. Meanwhile, an theoretically ultrahigh refractive index resolution (RIU) of 4.53 × 10-10 could be accessible for such a broad testing range, available for both gas and aqueous chemical sample refractive indices Furthermore, the power detection approach enables an integrated photodetector for a lab-on-chip sensor platform, revealing a high potential for a multifunctional, compact, and highly sensitive sensor-on-chip device.