  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 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.
