Risk assessment of airborne COVID-19 exposure in social settings.

The COVID-19 pandemic has led to many countries oscillating between various states of lock-down as they seek to balance keeping the economy and essential services running and minimizing the risk of further transmission. Decisions are made about which activities to keep open across a range of social settings and venues guided only by ad hoc heuristics regarding social distancing and personal hygiene. Hence, we propose the dual use of computational fluid dynamic simulations and surrogate aerosol measurements for location-specific assessment of risk of infection across different real-world settings. We propose a 3-tiered risk assessment scheme to facilitate classification of scenarios into risk levels based on simulations and experiments. Threshold values of <54 and >840 viral copies and <5% and >40% of original aerosol concentration are chosen to stratify low, medium, and high risk. This can help prioritize allowable activities and guide implementation of phased lockdowns or re-opening. Using a public bus in Singapore as a case study, we evaluate the relative risk of infection across scenarios such as different activities and passenger positions and demonstrate the effectiveness of our risk assessment methodology as a simple and easily interpretable framework. For example, this study revealed that the bus's air-conditioning greatly influences dispersion and increases the risk of certain seats and that talking can result in similar relative risk to coughing for passengers around an infected person. Both numerical and experimental approaches show similar relative risk levels with a Spearman's correlation coefficient of 0.74 despite differing observables, demonstrating applicability of this risk assessment methodology to other scenarios.

MRI of posterior eye shape and its associations with myopia and ethnicity.

PURPOSE: To evaluate posterior eye shape variations across a wide refractive error range using brain MRI in a multiethnic cohort. METHODS: Adult subjects in the multiethnic Singapore Epidemiology of Eye Disease study were included. Spherical equivalent (SE) was measured using subjective refraction, and axial length (AL) was measured using optical biometry. MRI was performed using a 3-Tesla whole body scanner with a 32-channel head coil. The radii and asphericity based on fitting of the posterior two-thirds of the eye (240°) were calculated. The refractive error status was categorised as myopic (SE<-0.5 D) or non-myopic (SE≥-0.5 D). RESULTS: A total of 450 adult participants (mean age 64.2±6.5 years old) were included. Less oblate asphericity was associated with more myopic SE, longer AL and with a refractive error categorisation of myopia (p<0.001 for all). Asphericity values were less oblate in myopic compared with non-myopic eyes (p<0.001). Multivariate analysis showed that Chinese subjects had less oblate eyes than Malay and Indian subjects, especially in non-myopic eyes. CONCLUSIONS: A less oblate posterior eye shape was associated with myopic eyes. Chinese eyes have less oblate shapes than Malay and Indian eyes, especially in non-myopic eyes.

Distribution and extent of electronic medical record utilisation in eye units across the United Kingdom: a cross-sectional study of the current landscape.

OBJECTIVES: Ophthalmology units across the UK vary widely in their adoption of electronic medical records (EMR). There is a lack of evidence to show the extent and progress of EMR adoption. The aim of this study was to capture a snapshot of the current landscape of EMR use, as a baseline for comparison in future studies. SETTING: An electronic survey questionnaire was sent to all NHS ophthalmology Units in the UK. PARTICIPANTS: A total of 104 National Health Service (NHS) ophthalmology units participated in the survey, which was carried out over 6 months from December 2013 to June 2014. PRIMARY AND SECONDARY OUTCOME MEASURES: Respondents were asked about technology usage pertaining to specific processes in the clinic workflow. This allowed us to determine the extent of EMR usage and details about current use or planned implementation by each unit. RESULTS: 77.6% (n=104) of NHS ophthalmology units responded. 45.3% (n=48) of units were currently using an EMR and a further 26.4% (n=28) of units plan to implement EMR within 2 years. 70.8% of units with a current EMR system use Medisoft. EMR is used by all clinicians in 37.5% and by all subspecialties offered at the unit in 27.0%. In 56.3%, new clinical notes are entered into EMR only by clinicians. All imaging devices are networked to EMR in 28.3%. In 46.7%, EMR is accessible by other specialties within the same hospital. 71.1% would recommend EMR to a colleague. CONCLUSIONS: EMR has the potential to address current limitations of patient information transfer and sharing in ophthalmology. It is pleasing to see a significant proportion of units already engaging with EMR or having plans to do so in the near future. However, differing EMR systems and lack of remote access mean further optimisation of these record systems are needed to allow data transfer between units.