Pulsed Ultrasound-Mediated Enhancement on Transscleral and Transconjunctival Fluorescein Sodium Delivery to Rabbit Eye In Vivo.

Purpose: To investigate the efficacy and safety of pulsed ultrasound (PUS) in enhancing fluorescein sodium (NaF) transport to the rabbit eye through the transscleral and transconjunctival routes in vivo. Methods: PUS and NaF were applied onto the supratemporal sclera/conjunctiva of healthy rabbit eyes. PUS (1 MHz, 2.37 W/cm2, 30% duty cycle, 5-min application time) was performed 3 times with a 5-min interval. In the same process, NaF was administered to the eye without PUS in the control. NaF concentrations in the vitreous and retina-choroid were determined by fluorescence measurement. The safety of PUS application was assessed based on temperature and intraocular pressure measurements, clinical observations, electroretinography, histology, and Terminal Deoxynucleotidyl Transferase dUTP Nick End Labeling assay. Results: In comparison to the control, higher NaF concentrations were found in the retina-choroid following transscleral (2.45-fold) and transconjunctival (2.97-fold) PUS applications (P < 0.05). NaF concentrations in the vitreous were 3.15 and 5.86 times greater in transscleral and transconjunctival PUS applications, respectively, compared with those obtained without PUS application (P < 0.05), and NaF level in the vitreous after transconjunctival PUS application was 2.61 times that of transscleral PUS application (P < 0.05). Ocular findings were transient and mild conjunctival injection, with no other structural and functional changes in PUS-treated eyes. Conclusions: PUS treatment can improve transscleral and transconjunctival delivery of NaF efficiently and safely. Transscleral and transconjunctival PUS applications offer potential clinical benefit in increasing drug penetration to the posterior segments of the eye for the noninvasive treatment of ocular diseases.

Cost-effectiveness of agents used for evaluation of ureteral patency during intraoperative cystoscopy in gynecologic and urogynecologic surgery.

BACKGROUND: Intraoperative evaluation of ureteral patency is often performed in gynecologic and urogynecologic surgery. Many agents are used to help assess the patency, each with its own associated cost, ease of use, and adverse reactions. Some agents, such as dextrose, are used as an instillation fluid to create a viscosity difference and aid the visualization of a ureteral jet. Others, such as oral phenazopyridine or the intravenous use of sodium fluorescein and indigo carmine, cause a color change of the urine to directly aid the visualization of ureteral jets. Recently, numerous studies have examined the efficacy and surgeon satisfaction of these agents. The studies have also emphasized certain options as associated with a lower cost. However, there have not been any cost studies comparing these agents. OBJECTIVE: To compare the cost-effectiveness of the following 4 agents that are commonly used in assessing ureteral patency intraoperatively: oral phenazopyridine, dextrose instillation, intravenous sodium fluorescein, and intravenous indigo carmine. STUDY DESIGN: We constructed a decision-analytic model to compare cystoscopy using oral phenazopyridine, dextrose instillation, intravenous sodium fluorescein, and intravenous indigo carmine. Failure to see efflux resulted in work-ups for ureteral obstruction. The probabilities were obtained from published studies, and the probability of successfully seeing efflux ranged from 0.92 with oral phenazopyridine to 0.99 with intravenous indigo carmine. The costs of the agents, adverse effects, and ureteral obstruction work-ups were obtained from the University of North Carolina at Chapel Hill Department of Pharmacy, the Healthcare Cost and Utilization Project 2016 database and the FAIR Health Consumer database. The cost of a ureteral obstruction work-up used in our model ranged from $9755 for intraoperative evaluation with retrograde pyelograms and stents to $29,034 for hospitalization. Our primary outcome was the incremental cost-effectiveness ratio per unnecessary work-up for ureteral obstruction avoided. Sensitivity analyses were performed to identify the key uncertainties. RESULTS: Oral phenazopyridine, followed by an intravenous agent if needed, had a mean cost of $110 per patient. Dextrose averaged $151 more per patient, with only a slight improvement in avoiding unnecessary ureteral obstruction work-ups and a higher cost associated with adverse reactions (incremental cost-effectiveness ratio, $62,000). Intravenous agents cost approximately $1000 more per patient and were less effective at preventing unnecessary work-ups. Sensitivity analyses did not identify any thresholds that would significantly change the outcomes. CONCLUSION: Our model suggests that oral phenazopyridine and dextrose instillation are the least expensive and the most effective agents to aid in the visualization of ureteral patency during intraoperative cystoscopy, although dextrose is associated with higher costs owing to a higher rate of adverse reactions (primarily urinary tract infections). Intravenous sodium fluorescein and indigo carmine are historically popular first-choice agents. However, they were found to be more expensive and less effective as primary agents in our model and should likely be reserved for use as secondary agents in the event that the visualization of ureteral jets is unclear with the initial use of phenazopyridine or dextrose.

Clinical comparison of tear film breakup time measurements in normal dogs using three different methods of fluorescein solution administration.

OBJECTIVE: To evaluate whether the method of fluorescein administration affects the results of tear film breakup time (TFBUT) measurement in normal dogs. ANIMALS STUDIED: Thirty-seven client and hospital staff owned dogs over 1 year of age with no known comorbidities or administration of systemic or topical ophthalmic medications. PROCEDURES: A prospective randomized three-way crossover study was conducted. All dogs received an abbreviated ophthalmic examination to rule out ocular surface disease. Using a 30-min washout interval period, each dog's right eye was received: (a) direct application of fluorescein stain strip with one drop of sterile eyewash, (b) direct application of fluorescein stain strip with two drops of sterile eyewash, or (c) application of one drop from a premade fluorescein solution (dilution of one strip in 0.3 mL sterile eyewash). Eyes were assessed using the cobalt blue filter of a slit lamp biomicroscope. TFBUT measurements were summarized as means ± standard deviation. The methods were compared using mixed model analysis of variance. All analyses were performed using sas version 9.4. RESULTS: Thirty-seven dogs met the inclusion criteria. Mean TFBUT ± standard deviation (SD) for the three described methods were: (a) 16.58s ± 6.9, (b) 15.98s ± 7.1, and (c) 16.43s ± 8.1. No differences between fluorescein stain application techniques were observed (p = .92). CONCLUSION: The technique of fluorescein solution administration did not affect TFBUT measurement in this population of healthy dogs.

Color Change of Intranasal Fluorescein Cannot Detect Cerebrospinal Fluid Leaks.

BACKGROUND: The color change of topical intranasal fluorescein has been used to confirm the presence of cerebrospinal fluid (CSF) during endoscopic endonasal surgery. We aimed to validate the use of topical intranasal fluorescein for CSF detection. METHODS: Blood, CSF, saliva, and normal saline were combined with decreasing fluorescein concentrations (from 10% to 0.1%). The solutions were photographed in high definition on nasal pledgets and in 1.5-mL Eppendorf tubes. The color difference (ΔE) was objectively measured via the International Commission on Illumination coordinates. Four otolaryngologists who were unaware of the study parameters also evaluated the samples for perceptible color differences. The human eye cannot detect color differences at an International Commission on Illumination ΔE of <5. RESULTS: All otolaryngologists agreed a color difference could be seen with blood across all fluorescein concentrations. However, a perceptible color difference between the experimental samples that excluded blood was not appreciable. Objectively, the ΔE was <5 on average for all nonblood samples when mixed with 5% and 10% fluorescein in the Eppendorf experiment. The ΔE for the nonblood samples was >5 for the remaining tested. Similarly, the average ΔE for the nonblood samples in the pledget experiment was >5 across all fluorescein concentrations. The blood ΔE was consistently >50 throughout all fluorescein concentrations in the Eppendorf experiment and >20 throughout the pledget experiment, correlating with the subjective ease of discernment between blood and the control sample in both groups. CONCLUSIONS: Color change alone is not sufficient to determine a difference between CSF, saliva, and saline. Blood, however, is readily identified using this method. Adjunct characteristics, in addition to the color change, are necessary to properly identify an active CSF leak.

Oral absorption characteristics and mechanisms of a pectin-type polysaccharide from Smilax china L. across the intestinal epithelium.

The elucidation of the oral absorption of natural polysaccharides contributes to their further research and utilization. Herein, to explore the absorption of a pectin-type polysaccharide from Smilax china L. (SCLP), SCLP was respectively fluorescently labeled with fluorescein-5-thioicarbazide (FSCLP) and Cyanine7 amine (Cy7-SCLP) for in vitro and in vivo tracking. The near-infrared imaging demonstrated that Cy7-SCLP was absorbable in the small intestine and distributed in the liver and kidney after oral administration. Subsequently, in vitro intestinal epithelial tissue experiments showed that the jejunum was the dominant site of FSCLP transport. Further transport studies in the Caco-2 cell monolayer illustrated that FSCLP was delivered across the monolayer via transcellular transport by caveolae-mediated endocytosis and macropinocytosis together with paracellular transport by reversibly affecting tight junctions. In summary, this work presents the oral absorption characteristics and mechanisms of SCLP through the intestinal epithelium, which will facilitate the further development of SCLP and pectin polysaccharides.

Characterization of the blood-brain barrier in genetically diverse laboratory mouse strains.

BACKGROUND: Genetic variation in a population has an influence on the manifestation of monogenic as well as multifactorial disorders, with the underlying genetic contribution dependent on several interacting variants. Common laboratory mouse strains used for modelling human disease lack the genetic variability of the human population. Therefore, outcomes of rodent studies show limited relevance to human disease. The functionality of brain vasculature is an important modifier of brain diseases. Importantly, the restrictive interface between blood and brain-the blood-brain barrier (BBB) serves as a major obstacle for the drug delivery into the central nervous system (CNS). Using genetically diverse mouse strains, we aimed to investigate the phenotypic and transcriptomic variation of the healthy BBB in different inbred mouse strains. METHODS: We investigated the heterogeneity of brain vasculature in recently wild-derived mouse strains (CAST/EiJ, WSB/EiJ, PWK/PhJ) and long-inbred mouse strains (129S1/SvImJ, A/J, C57BL/6J, DBA/2J, NOD/ShiLtJ) using different phenotypic arms. We used immunohistochemistry and confocal laser microscopy followed by quantitative image analysis to determine vascular density and pericyte coverage in two brain regions-cortex and hippocampus. Using a low molecular weight fluorescence tracer, sodium fluorescein and spectrophotometry analysis, we assessed BBB permeability in young and aged mice of selected strains. For further phenotypic characterization of endothelial cells in inbred mouse strains, we performed bulk RNA sequencing of sorted endothelial cells isolated from cortex and hippocampus. RESULTS: Cortical vessel density and pericyte coverage did not differ among the investigated strains, except in the cortex, where PWK/PhJ showed lower vessel density compared to NOD/ShiLtJ, and a higher pericyte coverage than DBA/2J. The vascular density in the hippocampus differed among analyzed strains but not the pericyte coverage. The staining patterns of endothelial arteriovenous zonation markers were similar in different strains. BBB permeability to a small fluorescent tracer, sodium fluorescein, was also similar in different strains, except in the hippocampus where the CAST/EiJ showed higher permeability than NOD/ShiLtJ. Transcriptomic analysis of endothelial cells revealed that sex of the animal was a major determinant of gene expression differences. In addition, the expression level of several genes implicated in endothelial function and BBB biology differed between wild-derived and long-inbred mouse strains. In aged mice of three investigated strains (DBA/2J, A/J, C57BL/6J) vascular density and pericyte coverage did not change-expect for DBA/2J, whereas vascular permeability to sodium fluorescein increased in all three strains. CONCLUSIONS: Our analysis shows that although there were no major differences in parenchymal vascular morphology and paracellular BBB permeability for small molecular weight tracer between investigated mouse strains or sexes, transcriptomic differences of brain endothelial cells point to variation in gene expression of the intact BBB. These baseline variances might be confounding factors in pathological conditions that may lead to a differential functional outcome dependent on the sex or genetic polymorphism.

Dissolvable microneedles based on Panax notoginseng polysaccharide for transdermal drug delivery and skin dendritic cell activation.

This work explored the feasibility of using biological polysaccharide to fabricate dissolvable microneedles (MNs) for the purpose of transdermal drug delivery and skin dendritic cell (DC) activation. Panax notoginseng polysaccharide (PNPS), a naturally derived immunoactive macromolecule, was used to fabricate dissolvable MNs. The prepared PNPS MNs showed a satisfactory mechanical strength and a skin penetration depth. By Franz diffusion cell assay, the PNPS MNs demonstrated a high transdermal delivery amount of model drugs. Furthermore, with the assistance of MNs, PNPS easily penetrated across the stratum corneum and target ear skin DCs, activating the maturation and migration of immunocytes by increasing the expressions of CD40, CD80, CD86, and MHC II of skin DCs. Consequently, the matured DCs migrated to the auricular draining lymph nodes and increased the proportions of CD4+ T and CD8+ T cells. Thus, PNPS might be a promising biomaterial for transdermal drug delivery, with adjuvant potential.

Reliability and efficacy of maximum fluorescein tear break-up time in diagnosing dry eye disease.

This study aims to investigate the reliability and efficacy of maximum fluorescein tear break-up time (FTBUTmax) in diagnosing dry eye disease (DED). 147 participants were enrolled in this study. Ocular symptoms were assessed by Ocular Surface Disease Index (OSDI). The fluorescein tear break-up time (FTBUT) examination, corneal fluorescein staining (CFS), and Schirmer I test were performed on both eyes. Each participant underwent 3 consecutive FTBUT tests, and five types of FTBUT values including FTBUTmax, the minimum FTBUT (FTBUTmin), the first FTBUT (FTBUT1), the average of three FTBUTs (FTBUT123) and the average of the first and second FTBUT (FTBUT12) were recorded. FTBUTmax was larger than the other FTBUT values, but no differences were found among the values of FTBUT1, FTBUT123, FTBUT12 and FTBUTmin. In the ROC analysis, FTBUTmax had the largest or the second largest area under the ROC (AUROC) in all three DED diagnostic criteria, while FTBUTmin had the least AUROC of them. ROC efficacy of FTBUTmax was significantly higher than that of FTBUT123, FTBUT12, FTBUT1 and FTBUTmin in the OSDI criteria and higher than that of FTBUT1 and FTBUTmin in Schirmer I test and CFS tests. FTBUTmax has a close correlation with OSDI, Schirmer I test and CFS, and is an effective tool for the DED diagnosis.

Enhancement of Skin Permeation of a Hydrophilic Drug from Acryl-Based Pressure-Sensitive Adhesive Tape.

PURPOSE: Penetration enhancers are necessary to overcome a formidable barrier function of the stratum corneum in the development of topical formulations. Recently, non-lamella liquid crystal (NLLC)-forming lipids such as glycerol monooleate and phytantriol (PHY) are gaining increasing attention as a novel skin permeation enhancer. In the present study, fluorescein sodium (FL-Na) was used as a model hydrophilic drug, and acryl-base pressure-sensitive adhesive (PSA) tape containing NLLC forming lipids, mono-O-(5,9,13-trimethyl-4-tetradecenyl) glycerol ester (MGE) or PHY, was prepared to enhance drug permeation through the skin. METHODS: A PSA patch containing FL-Na was prepared by mixing FL-Na entrapped in NLLC and acrylic polymer. FL permeation through excised hairless rat skin, and also human skin, was investigated. Changes in lipid structure, folding/unfolding state of keratin in the stratum corneum, and penetration of MGE into the stratum corneum were investigated using confocal Raman microscopy. RESULTS: Enhanced FL permeation was observed by the application of a PSA patch containing MGE and PHY. Especially, dramatically enhancement effect was confirmed by 15% of MGE contained formulation. Penetration of MGE provided diminished orthorhombic crystal structure and a peak shift of the aliphatic CH3 vibration of keratin chains toward lower wavenumbers. CONCLUSION: The present results suggested that the formulation development by adding MGE may be useful for improving the skin permeation of mal-permeable drugs such as hydrophilic drugs.

A Randomized Clinical Study (SEECASE) to Assess Efficacy, Safety, and Tolerability of NOV03 for Treatment of Dry Eye Disease.

PURPOSE: NOV03 has a unique dual mode of action to address dry eye disease (DED) associated with meibomian gland dysfunction. SEECASE evaluated the efficacy, safety, and tolerability of NOV03 at 2 dosing regimens compared with a saline comparator in patients with DED. METHODS: SEECASE was a prospective, multicenter, randomized, double-masked, saline-controlled clinical study. A total of 336 DED patients [tear film breakup time ≤5 seconds, abnormal meibum secretion, total corneal fluorescein staining (tCFS) score of 4 ≤ X ≤ 11 (National Eye Institute scale), Schirmer of ≥5 mm] were randomized in a 2:2:1:1 manner to NOV03 4 times daily (QID), NOV03 twice daily (BID), saline BID, and saline QID, respectively. The primary efficacy endpoint was tCFS staining at 8 weeks for both regimens. Secondary endpoints included visual analog scales and the Ocular Surface Disease Index questionnaire for symptom assessment. RESULTS: The study met its primary endpoint, change from baseline of tCFS over control, for both dosing regimens QID and BID (P < 0.001 and P = 0.009, respectively). NOV03 also showed pronounced improvement in various symptoms. For the Eye Dryness Score, changes from baseline were statistically significant compared with those of the control at week 8 [P < 0.001 (QID) and P = 0.002 (BID)]. Benefits on tCFS and symptoms started at 2 weeks after start of treatment and were maintained over the study duration. The effects were dosing schedule dependent. NOV03 was well tolerated with instillation site reactions below 3% in both treatment regimes. CONCLUSIONS: The SEECASE study demonstrated that NOV03 improves signs and symptoms in patients with highly symptomatic evaporative dry eye disease.

Changes in Corneal Subbasal Nerves after Punctal Occlusion in Dry Eye Disease.

PURPOSE: To evaluate corneal subbasal nerve plexus by in vivo confocal microscopy (IVCM) following punctal occlusion in patients with moderate to severe dry eye disease (DED). MATERIALS AND METHODS: Patients with grade 3 or 4 severity of DED based on Delphi Panel dry eye severity grading scheme were enrolled in the study. Permanent inferior punctal occlusion was performed. A comprehensive ophthalmic evaluation, including Ocular Surface Disease Index (OSDI) questionnaire, tear break-up time (TBUT), corneal fluorescein staining, conjunctival Rose bengal staining, Schirmer's test, and corneal sensation by Cochet-Bonnet esthesiometry, were performed at baseline, and 1 and 3 months after punctal occlusion. Furthermore, density and number of corneal subbasal nerves were evaluated by IVCM. RESULTS: Forty-one eyes of 23 patients with a mean age of 46.3 ± 9.0 years were enrolled. Corneal fluorescein staining, Rose bengal staining, and TBUT significantly improved at 3 months following punctal occlusion (p < .015). Corneal esthesiometry significantly increased at both postoperative visits (p < .03), and OSDI scores improved only at 3-month follow-up (p < .005). Nerve density and total number significantly increased 3 months after punctal occlusion (p < .045). Baseline nerve density had significant correlations with TBUT, fluorescein staining, Rose bengal staining (p < .012), but not with esthesiometry, Schirmer scores, or OSDI scores (p > .329). CONCLUSIONS: Corneal subbasal nerve density and total number increased following punctal occlusion in patients with moderate to severe DED. These findings were associated with improvements in corneal sensation, and signs and symptoms of DED. This emphasizes the effect of punctal occlusion in regeneration of corneal subbasal nerve plexus.

In Vivo Confocal Microscopy Morphometric Analysis of Meibomian Glands in Patients With Graves Ophthalmopathy.

PURPOSE: To characterize meibomian glands (MGs) features in patients with Graves ophthalmopathy (GO) by in vivo confocal microscopy (IVCM) and to further investigate possible correlations with ocular surface characteristics. METHODS: Consecutive patients with GO and controls were enrolled. The following ocular surface parameters were measured: tear break-up time, Schirmer test, and corneal fluorescein staining (Oxford score) were performed on each subject. IVCM of MGs was performed, and the scans were analyzed with ImageJ software for the calculation of the following: acinar unit density, total gland area, total lumen area (TLA), acinar longest diameter, and acinar shortest diameter. A nonparametric Mann-Whitney U test was used to compare variables between patients with GO and controls. The Spearman correlation analysis was used to evaluate the correlations between ocular surface and IVCM parameters. RESULTS: Twenty-one patients with GO and 24 sex- and age-matched healthy controls were included. Acinar unit density was significantly lower in patients with GO compared with controls (24.5 ± 8.1 vs. 34.2 ± 7.5 U/mm; P < 0.001). In addition, patients with GO showed significantly higher values of TLA, acinar longest diameter, and acinar shortest diameter compared with controls (respectively, 3104.7 ± 1713.3 vs. 1393.8 ± 448.0 µm, 94.4 ± 21.2 vs. 64.3 ± 10.1 µm and 56.6 ± 15.3 vs. 42.2 ± 12.3 µm; always P < 0.05). In patients with GO, TLA showed a significant inverse correlation with Schirmer test (Rs = -0.467; P = 0.038). CONCLUSIONS: IVCM allowed to detect distinctive features of MGs in patients with GO and could represent a surrogate tool for the assessment of MG status in these patients.

Thermal Effects on Fluid Mixing in the Eye.

Age-related macular degeneration (AMD) is the leading cause of central vision loss in the developed world. Wet AMD can be managed through serial intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) agents. However, sometimes the treatment is ineffective. Given that the half-life of the drug is limited, inefficient mixing of the injected drug in the vitreous chamber of the eye may contribute to the ineffectiveness. Here, we introduce thermal heating as a means of enhancing the mixing-process in the vitreous chamber and investigate parameters that potentially influence its effectiveness. Our in vitro studies reveal the importance of the heating location on the eye. A significant increase in the mixing and delivery of drugs to the targeted area (the macula) could be achieved by placing heating pads to induce a current, against gravity, in the vitreous. The presented results can potentially help in the development of a better strategy for intravitreal injection, subsequently improving the quality of patient care.

Subjective and Objective Evaluation of the Effect of Blink Type on Tear-film Breakup Time and Its Estimation.

SIGNIFICANCE: While evaluating the tear-film breakup time, a careful set of precise instructions should be given to the subjects regarding the blink type because it substantially impacts the assessment of tear-film surface quality. PURPOSE: The purpose of this study was to determine to what extent the type of blink affects the tear-film breakup time and its assessment using two types of videokeratoscopes and the fluorescein test. METHODS: Thirty-three volunteers were assessed considering two different types of blinks: natural (short) and forced (unnaturally prolonged). Objective noninvasive breakup time estimation was performed using Oculus Keratograph 5M and Medmont E300, both equipped with tear-film analysis modules, followed by the fluorescein test. In addition, while overviewing videokeratoscopy recordings, noninvasive breakup time was assessed subjectively by one experienced observer marking the first noticeable distortion in the Placido-disk pattern. Statistical analyses included two-way ANOVA and paired-sample t test. The agreement between blinking and measuring modalities was assessed using Bland-Altman plots. RESULTS: Forced blink significantly shortened the tear-film breakup time in all measuring modalities (two-way ANOVA, P = .003). The mean difference between breakup time after natural and forced blink was 3.2 (P = .002), 2.4 (P = .005), and 2.1 seconds (P = .002), for Keratograph 5M, E300, and fluorescein test, respectively. The group median of differences between objective and subjective noninvasive breakup time was less than 1 second with both videokeratoscopes. The objective noninvasive breakup time measured with Keratograph 5M was significantly longer than those with E300 and fluorescein test (both P < .001). No statistically significant difference was found between E300 objective assessment and fluorescein test (P = .19). CONCLUSIONS: Forced blinks affect the assessment of tear-film stability. Hence, attention should be given in instructing the subjects before tear-film breakup time evaluation irrespectively to the method of measurement.

Versatile composite hydrogels for drug delivery and beyond.

Hydrogels have extended applications across multiple fields. A novel hydrogel material is often evaluated for its properties and applications in either a wet or dry state, but not both. In this study, we investigated a protein-based, composite hydrogel system in both its wet and dry states. Bovine serum albumin (BSA) was used as the hydrogel base. With the assistance of organosilanes, BSA solutions became hydrogels under facile reaction conditions. In the first part, the wet gel was prepared in situ in a syringe; upon injecting through a needle, the gel retained its structure. The use of the nascent gel system as an injectable drug-delivery vehicle is of particular interest. We therefore developed a microplate platform that allows a "one-plate" study-i.e. gel preparation, payload loading and release-all being performed in a single plate. This one-plate method further enables a systematic study of various controlling parameters for drug release. For example, we can tune the release rate by simply adjusting the phosphate content in the hydrogel formulation. Besides, for low-releasing compounds, the release profile was also tunable while using the one-plate method. In the second part, we further demonstrate the versatility of our composite hydrogels. By simply varying the feed ratio of two organosilanes, (3-mercaptopropyl)methyldimethoxysilane and (3-mercaptopropyl)trimethoxysilane, and phosphate concentrations, dry gels exhibiting various absorption capacities towards water, organic solvents, and oil can be prepared. Further characterizations using SEM and 29Si NMR spectroscopy revealed porous structures and hybrid siloxane bridges within the composite material.

Quantitative High-speed Assessment of Droplet and Aerosol From an Eye After Impact With an Air-puff Amid COVID-19 Scenario.

PURPOSE: To quantify aerosol and droplets generated during noncontact tonometry (NCT) and assess the spread distance of the same. METHODOLOGY: This was an experimental study on healthy human volunteers (n=8 eyes). In an experimental setup, NCT was performed on eyes (n=8) of human volunteers under normal settings, with a single and 2 drops of lubricant. High-speed shadowgraphy, frontal lighting technique, and fluorescein analysis were used to detect the possible generation of any droplets and aerosols. Mathematical computation of the spread of the droplets was then performed. RESULTS: In a natural setting, there was no droplet or aerosol production. Minimal splatter along with droplet ejection was observed when 1 drop of lubricant was used before NCT. When 2 drops of lubricant were instilled, a significant amount of fluid ejection in the form of a sheet that broke up into multiple droplets was observed. Some of these droplets traversed back to the tonometer. Droplets ranging from 100 to 500 µm in diameter were measured. CONCLUSIONS: There was no droplet generation during NCT performed in a natural setting. However, NCT should be avoided in conditions with high-tear volume (natural or artificial) as it would lead to droplet spread and tactile contamination.

A comparison of droplet and contact contamination using 3 simulated barrier techniques for COVID-19 intubation: a quality assurance study.

BACKGROUND: The intubation of patients with coronavirus disease 2019 (COVID-19) puts health care workers at risk of infection through aerosol, droplet and contact contamination. We evaluated the risk of droplet and contact contamination for health care workers using 3 intubation barrier techniques as part of a quality assurance study at our institution. METHODS: This randomized quality assurance study was completed at a tertiary academic hospital in Vancouver, British Columbia, Canada, on Apr. 4, 2020. Participants in personal protective equipment performed simulated intubations on a manikin with (a) no barrier, (b) a clear plastic sheet covering the manikin and (c) a plexiglass intubation box over the manikin, in random order. Fluorescein was ejected from inside the manikin's mouth to simulate droplet and contact spread during a standard intubation sequence. Two blinded independent assessors evaluated the location and degree of contamination on the intubator and assistant using an ultraviolet light. Contamination severity was rated in a standard fashion (0 = none; 1 = minor; 2 = major). The primary outcome was total contamination score and secondary outcomes were scores between intubator and assistant, anatomic areas contaminated and qualitative feedback on ease of intubation. RESULTS: Five participants completed this study. Total contamination score was different between the 3 groups for the intubator (p = 0.02) but not the assistant (p = 0.2). For the intubator, the total contamination score was higher when the sheet was used (median 29 [interquartile range (IQR) 25-34]) than when the box was used (median 17 [IQR 15-22]) or when no barrier was used (median 18 [IQR 13-21]). All 5 participants reported challenges during intubation using the sheet. INTERPRETATION: Use of a plastic sheet while intubating patients with COVID-19 may increase the risk of droplet and contact contamination during intubation and impede intubation. Further study should be undertaken before implementing barrier techniques in practice.

Association of the Indoor Environment With Dry Eye Metrics.

Importance: The ocular surface is continuously exposed to the environment. Although studies have focused on associations between outdoor environmental conditions and dry eye, information on associations between the indoor environment and dry eye is lacking. Objective: To determine associations between the indoor environment and dry eye. Design, Setting, and Participants: This prospective cross-sectional study sample of 97 veterans with a wide range of dry eye metrics was recruited from the Miami Veterans Affairs Healthcare eye clinic from October 19, 2017, to August 30, 2018. Dry eye metrics were first evaluated in the clinic, followed by indoor home environmental metrics within 1 week using a handheld particle counter. Data were analyzed from October 19, 2017, to August 30, 2018. Main Outcomes and Measures: Symptoms of dry eye were assessed with standardized questionnaires. Dry eye signs were assessed via standard examination. Indoor environmental metrics included temperature, humidity, and particulate matter mass and count. Results: Of the 97 participants included in the analysis, 81 (84%) were men, with a mean (SD) age of 58.2 (11.9) years. Dry eye symptoms were in the moderate range with a mean (SD) Ocular Surface Disease Index (OSDI) score of 31.2 (23.6). Humidity was associated with worse symptoms and signs, including OSDI score (r = 0.30 [95% CI, 0.07-0.49]; P = .01), inflammation (r = 0.32 [95% CI, 0.10-0.51]; P = .01), Schirmer score (r = -0.25 [95% CI, -0.45 to 0.02]; P = .03), eyelid vascularity (r = 0.27 [95% CI, 0.05-0.47]; P = .02), and meibomian gland dropout (r = 0.27 [95% CI, 0.05-0.47]; P = .02). In multivariate analyses, particulate matter of 2.5 µm or less (PM2.5) was associated with dry eye metrics when adjusted for demographic characteristics, comorbidities, medications, and interaction variables. For example, a 1-unit increase in instrumented PM2.5 level was associated with a 1.59 increase in the OSDI score (95% CI, 0.58-2.59; P = .002), a 0.39 reduction in Schirmer score (95% CI, -0.75 to -0.03; P = .04), a 0.07 increase in meibomian gland dropout (95% CI, 0.01-0.13; P = .02), and a 0.06 increase in inflammation (95% CI, 0.02-0.11; P = .009). Conclusions and Relevance: When adjusting for humidity, this study found that increased particulate matter exposure was associated with worse dry eye metrics. Humidity was positively associated with dry eye metrics, potentially because higher humidity increases microbial growth and particulate matter size and mass.