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The aim is to analyze automated quantification of choriocapillaris flow deficit (CCFD) on swept-source (SS)-optical coherence tomography angiography (OCTA) in tubercular serpiginous-like choroiditis (TBSLC). In this prospective study, automated CCFD calculations were performed on SS-OCTA and compared with CCFD areas on indocyanine green angiography (ICGA). Patients were divided into two groups based on the occurrence of paradoxical worsening (PW). Twenty-nine eyes (29 subjects; 18 males; mean age: 33±12 years) were included. The mean CCFD at baseline was 34.9 ± 4.3% on OCTA in eyes without PW and 35.4 ± 5.0% on SS-OCTA with PW (p =.77). At 4 and 12 weeks, CCFD on SS-OCTA improved to 30.6 ± 3.9% and 28.0 ± 4.2% (p <.001) without PW, respectively, and increased to 42.9 ± 4.4% and 48.8 ± 4.1% (p <.001) with PW, respectively. The SS-OCTA CCFD correlated well with ICGA (r = 0.48; p <.001). Automated quantitative serial assessment of CCFD on SS-OCTA can serve as a useful biomarker of disease activity in eyes with TBSLC. [ABSTRACT FROM AUTHOR]

The purpose of this systematic review is to identify techniques used for quantification of choriocapillaris (CC) flow in eyes with uveitis using optical coherence tomography angiography (OCTA), report reliability and level of correlation with techniques such as indocyanine green angiography (ICGA). A systematic search of several databases was done. The studies were analyzed for techniques of measurement, reliability, and correlation with other modalities. Risk of bias assessment was performed. Thirteen studies were included. CC vessel density (7 studies) and flow deficit area (4 studies) were the most used indices. There was significant heterogeneity in the studies due to differences in the scan protocol, thresholding strategy, and analysis. Comparison with ICGA was performed by only one study, and reliability indices were reported by only two studies. OCTA is a useful tool to measure the CC vascularity in eyes with uveitis. However, standardized acquisition and analysis protocols are needed. [ABSTRACT FROM AUTHOR]

To quantify retinochoroidal vascular parameters using swept-source optical coherence tomography (SS-OCTA) in quiescent posterior and panuveitis. In this cross-sectional study, subjects with quiescent posterior and panuveitis underwent fundus imaging using SS-OCTA (DRI Triton®, Topcon, Japan). The metrics calculated were fractal dimension (FD), foveal avascular zone (FAZ) area, retinal vascularity index (capillary density index-CDI), and choroidal vascularity index (CVI). We included 38 eyes of 20 patients, 9 males aged 34.7 ± 10.5 years, 30 eyes of 30 age- and gender-matched healthy controls, 10 females aged 33.6 ± 8.5 years. Comparing patients with controls, we found a lower FD (p <.001), larger FAZ (p >.001), lower CDI in the superficial plexus (p =.019), and lower CVI (p <.001). We also found lower retinal and choroidal and thicknesses (p <.001 and p =.025, respectively). Patients with quiescent posterior and panuveitis have a significantly reduced retinochoroidal vascular density compared to healthy control subjects. [ABSTRACT FROM AUTHOR]

A dark‐field ophthalmic contact probe for analysis of aqueous humor (AH) was designed by ray tracing and constructed in quartz glass for experimental use as a prototype probe in a confocal Raman spectroscopic setup. The misalignment tolerance of this probe was theoretically evaluated, whereas the optical performance was experimentally evaluated by a concentration curve of the ocular drug phenylephrine HCl in an artificial eye model. The results indicated a ninefold improvement in misalignment tolerance and a 36‐fold improvement in the signal‐to‐noise ratio at the phenylephrine HCl 1002 cm−1 peak compared with a previous design. The prototype showed a good linear fit with the phenylephrine HCl concentration, with an R2 of 0.996. Phenylephrine HCl concentration down to 0.1% is detectable. [ABSTRACT FROM AUTHOR]

Purpose: Raman spectroscopy holds potential for the assessment of intraocular pharmacokinetics. Raman spectra of ocular drugs were acquired, to determine the drug-specific Raman signature. The ability of the Raman technique to quantify drug concentrations was also investigated. Methods: The experimental setup was based on a High Performance Raman Module 2500 Raman module, designed for 180° 'backscatter' signal detection in the wavenumber range of 400-1,800 cm−1. Excitation source was a diode laser emitting a beam with a wavelength of 785 nm and a power of 10 mW. Laser light was focused in the sample with a long-working-distance microscope objective (25×/0.50). Samples were measured in quartz cuvettes in 10 sequential measurements, with exposure time 30 s. The total number of measured drugs was 49. To determine whether signal intensity and drug concentration correlate, 2 drugs were diluted in water and measured with 120 s exposure time at different concentrations. Results: An active ingredient-specific Raman signature was detected in 4 glaucoma drugs, 6 mydriatics, 5 antibiotics, 4 anesthetics, 3 anti-inflammatory drugs, 2 types of artificial tears, and 5 other drugs. In 20 drugs, no specific Raman signature was detected. Linear correlation of drug concentration with signal intensity was high ( R2≥0.94). Conclusions: Using low laser powers, Raman signatures for 29 commonly used ocular drugs were detected. Correlation of drug concentration with signal intensity is high, which is essential for monitoring drug concentration in ocular media. The presented results encourage the use of Raman spectroscopy to acquire detailed information on the pharmacokinetics of these ocular drugs. [ABSTRACT FROM AUTHOR]

To obtain a real-time noninvasive analysis of the content of the aqueous humor (AH) in the eye, a confocal dark-field ophthalmic probe was designed and optimized by ray-tracing software. The confocal technique allows Raman spectrometric sampling of the AH with suppressing signals from the surrounding tissues. Dark-field illumination prevents the excitation light to reach the vulnerable retinal tissue directly. In order to evaluate the optical performance and safety of this method, a functional prototyped eye contact probe has been designed and tested on ex vivo rabbit eyes. [ABSTRACT FROM AUTHOR]

Current information about the pharmacokinetics of an ocular drug can only be achieved by invasive sampling. However, confocal Raman spectroscopy bears the potential to quantify drug concentrations non-invasively. In this project, we evaluated the detection and quantification of ocular ketorolac tromethamine levels with confocal Raman spectroscopy after topical administration. Confocal Raman spectroscopy and high-performance liquid chromatography (HPLC) were compared in terms of sensitivity of detection. Enucleated pig eyes were treated with different concentrations of ketorolac. Hereafter, ketorolac concentrations in the aqueous humor of pig eyes were analyzed by confocal Raman spectroscopy and HPLC. Subsequently, twelve rabbits were treated with Acular™ for four weeks. At several time points, ketorolac concentrations in aqueous humor of the rabbits were measured by confocal Raman spectroscopy followed by drawing an aqueous humor sample for HPLC analysis. In ketorolac treated pig eyes, both ex vivo Raman spectroscopy as well as HPLC were able to detect ketorolac in a broad concentration range. However, in vivo confocal Raman spectroscopy in rabbits was unable to detect ketorolac in contrast to HPLC. To conclude, confocal Raman spectroscopy has the capacity to detect ketorolac tromethamine in vitro , but currently lacks sensitivity for in vivo detection. [ABSTRACT FROM AUTHOR]