Aerosol generation from tear film during non-contact tonometer measurement

Qin, Zhou; Shang, Xinglong; Chen, Xiaodong; Chen, Yanyan; Hu, Guoqing

doi:10.1063/5.0101917

Cited by 3 publications

(2 citation statements)

References 62 publications

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“…Further, in our recent study, we also deciphered the mechanism of tear film destabilization that leads to droplet generation and possibly a pathogen transmission mechanism through the corneal tear film disintegration and aerosolization. 25,27 The tear film disintegration process and aerosol generation were later confirmed computationally by a recent work of Zhou et al 61 The mechanics of NCT are, therefore, complex and include phenomena on various spatiotemporal scales. The measurement of the IOP depends on accurately estimating the applanation distance (distance between the tonometer nozzle exit and the cornea), flow field characteristics of the incoming jet, corneal elastic properties, and the aqueous humour.…”

Section: Introductionmentioning

confidence: 84%

Future research perspective on the interfacial physics of non-invasive glaucoma testing in pathogen transmission from the eyes

Roy,

Basu

2024

Biointerphases

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Non-contact tonometry (NCT) is a non-invasive ophthalmologic technique to measure intraocular pressure (IOP) using an air puff for routine glaucoma testing. Although IOP measurement using NCT has been perfected over many years, various phenomenological aspects of interfacial physics, fluid structure interaction, waves on corneal surface, and pathogen transmission routes to name a few are inherently unexplored. Research investigating the interdisciplinary physics of the ocular biointerface and of the NCT procedure is sparse and hence remains to be explored in sufficient depth. In this perspective piece, we introduce NCT and propose future research prospects that can be undertaken for a better understanding of the various hydrodynamic processes that occur during NCT from a pathogen transmission viewpoint. In particular, the research directions include the characterization and measurement of the incoming air puff, understanding the complex fluid-solid interactions occurring between the air puff and the human eye for measuring IOP, investigating the various waves that form and travel; tear film breakup and subsequent droplet formation mechanisms at various spatiotemporal length scales. Further, from an ocular disease transmission perspective, the disintegration of the tear film into droplets and aerosols poses a potential pathogen transmission route during NCT for pathogens residing in nasolacrimal and nasopharynx pathways. Adequate precautions by opthalmologist and medical practioners are therefore necessary to conduct the IOP measurements in a clinically safer way to prevent the risk associated with pathogen transmission from ocular diseases like conjunctivitis, keratitis, and COVID-19 during the NCT procedure.

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Section: Introductionmentioning

confidence: 84%

Future research perspective on the interfacial physics of non-invasive glaucoma testing in pathogen transmission from the eyes

Roy,

Basu

2024

Biointerphases

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“…The coupled continuity and momentum equations were solved using the pressure implicit with the splitting of the operator method. At each computing step, the time step t is automatically adjusted based on the Courant-Friedrichs-Lewy condition, where the maximum Courant number Co is set as 0.5 (Zhou et al 2022). To manage the substantial computational cost associated with solving the N-S equations together with the VOF method, we focused our simulations on a reduced 3-D domain, specifically a 1/4 × 1/4 portion of the original microfluidic chip.…”

Section: Experimental Set-up and Proceduresmentioning

confidence: 99%

Fluid entrapment during forced imbibition in a multidepth microfluidic chip with complex porous geometry

Lei,

Gong,

et al. 2024

J. Fluid Mech.

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Understanding and controlling fluid entrapment during forced imbibition in porous media is crucial for many natural and industrial applications. However, the microscale physics and macroscopic consequences of fluid entrapment in these geometric-confined porous media remain poorly understood. Here, we introduce a novel multidepth microfluidic chip, which can mitigate the depth confinement of traditional two-dimensional (2-D) microfluidic chips and mimic the wide pore size distribution as natural-occurring three-dimensional (3-D) porous media. Based on microfluidic experiments and direct numerical simulations, we observe the fluid-entrapment scenarios and elucidate the underlying complex interaction between geometric confinement, capillary number and wettability. Increasing depth variation can promote fluid entrapment, whereas increasing capillary number and contact angle yield the opposite effect, which seemingly contradicts conventional expectations in traditional 2-D microfluidic chips. The fluid-entrapment scenario in depth-variable microfluidic chips stems from microscopic interfacial phenomena, classified as snap-off and bypass events. We provide theoretical analyses of these pore-scale events and validate corresponding phase diagrams numerically. It is shown that increasing depth variation triggers snap-off and bypass events. Conversely, a higher capillary number suppresses snap-off events under strong imbibition, and an increased contact angle inhibits bypass events under imbibition. These macroscopic imbibition patterns in microfluidic porous media can be linked with these pore-scale events by improved dynamic pore-network models. Our findings bridge the understanding of forced imbibition between 2-D and 3-D porous media and provide design principles for newly engineered porous media with respect to their desired imbibition behaviours.

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Constitutive modeling of human cornea through fractional calculus approach

Mandal

Chattopadhyay

Halder³

2023

Physics of Fluids

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In this work, fractional calculus approach is considered for modeling the viscoelastic behavior of human cornea. It is observed that the degree of both elasticity and viscosity is easy to describe in terms of the fractional order parameters in such approach. Modeling of the human cornea when subjected to simple stress up to the level of 250 MPa by Fractional order Maxwell Model along with the Fractional Kelvin Voigt Viscoelastic Model is reported. For the Maxwell governing fractional equation, two fractional parameters α and β have been considered to model the stress-strain relationship of human cornea. The analytical solution of the fractional equation has been obtained for different values of α and β using Laplace transform methods. The effect of the fractional parameter values on the stress-deformation nature has been studied. A comparison between experimental values and calculated values for different fractional order of the Maxwell model equation define the parameters which depicts the real time stress-strain relationship of human cornea. It has been observed that the fractional model converges to the classical Maxwell model as a special case for α = β = 1.

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Aerosol generation from tear film during non-contact tonometer measurement

Cited by 3 publications

References 62 publications

Future research perspective on the interfacial physics of non-invasive glaucoma testing in pathogen transmission from the eyes

Future research perspective on the interfacial physics of non-invasive glaucoma testing in pathogen transmission from the eyes

Fluid entrapment during forced imbibition in a multidepth microfluidic chip with complex porous geometry

Constitutive modeling of human cornea through fractional calculus approach

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