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Aims: Recently, chemically modified silicone oil has been demonstrated as a reservoir for sustained release of intraocular drugs, many of which might be amphiphilic in nature. In this work, we study the effect of amphiphilic additives in silicone oil on emulsification under eye‐like movements. Methods: Three silicone‐oil‐soluble surfactants, namely DC749, MQ1640 and FZ2233, were used as model amphiphilic additives. The change of viscosity was measured by a rheometer in the cone‐and‐plate geometry. The interfacial tension (IFT) between silicone oil and model aqueous phase was measured by pendant drop tensiometry. Emulsification of silicone oil was induced by simulated saccadic eye movements on a cell‐coated eye‐on‐a‐chip platform for 4 days. The number of emulsified silicone oil droplets observed in the aqueous phase was assessed daily by optical microscopy. Results: Significantly more emulsified droplets were formed in silicone oil with DC749 or MQ1640 (P < 0.05). However, such increase was not directly related to the change in IFT nor viscosity. Moreover, water droplets were also found in the silicone oil, but not in the control silicone oil without additive. Conclusions: The amphiphilic substances in silicone oil promoted emulsification. Besides typical oil‐in‐water drops that normally affect the eye, water‐in‐oil drops were also formed. Before silicone oil could be considered as a vehicle for drug delivery, the nature of the drug and its possible effect on emulsification and therefore on the pharmacokinetics needs to be investigated. An additional concern is that water‐in‐oil droplets in the eye would affect the optical clarity of silicone oil and might cause visual symptoms. [ABSTRACT FROM AUTHOR]

Purpose: Silicone oil (SiO) with additives of high‐molecular‐weight (HMW) SiO molecules, eases both the injection and removal. When used inside an eye, it remains unclear how increasing extensional viscosity of SiO might reduce emulsification. Using cell‐lined models, this study aims to understand the reason why SiO with HMW is less prone to emulsification. Methods: The adhesion of SiO was studied and recorded in a cell‐coated microchannel by optical microscopy. The resistance of SiO against emulsification was tested on another cell‐coated eye‐on‐a‐chip platform, which was subject to simulated saccadic eye movements, for 4 days. Silicone oil (SiO) candidates with HMW, SiOHMW2000 and SiOHMW5000, and their counterparts SiO2000 and SiO5000 without HMW, were tested. The quantity of the SiO emulsified droplets formed was assessed daily by optical microscopy. Results: When flowing in the microchannel, SiO adheres on the cell‐coated substrate. The number of droplets is generally lower in SiO with HMW than their counterparts. At the end of the experiment, the average numbers of droplets in SiO2000 (29.1 ± 41.0) and SiO5000 (9.1 ± 19.5) are higher than those in SiOHMW2000 (6.0 ± 4.5) and SiOHMW5000 (5.6 ± 4.1). Conclusion: A new mechanism of emulsification of SiO is proposed: SiO adheres to ocular tissue to form emulsified droplets. The presence of HMW, which increases the extensional viscosity, may resist the break‐up of SiO from the substrate to form emulsified droplets. When tested in a physiologically representative platform, the use of HMW in SiO generally reduces the number of droplets formed in vitro. [ABSTRACT FROM AUTHOR]

The article discusses how the COVID-19 pandemic has changed the way clinical skill teaching is conceived and delivered. Topics covered include how medical education responded and adapted when routine bed-side teaching is impossible because of school suspension, lockdown and social distancing measures, the popularity of the incorporation of teleconference practice by means for routine ward teaching, and the limitations of videoconference-based teaching.

Abstract: Importance: Diabetes mellitus is known to be associated with dry eye syndrome (DES), but the effects of long‐term glycaemic control on tear film metrics and dry eye symptoms are not known in the Chinese population. Background: To evaluate tear film stability and dry eye symptoms and their associations with systemic risk factors in Chinese patients with type 2 diabetes mellitus (T2DM). Design: Cross‐sectional study set at the Lo Fong Siu Po Eye Centre (Grantham Hospital), Hong Kong. Participants: A total of 80 Chinese participants, aged 18 or above, with T2DM recruited from the specialist outpatient setting were included. Methods: The Oculus Keratograph 5M (Oculus Inc., Wetzlar, Germany) was used to measure the non‐invasive tear break‐up time (NITBUT). Ocular symptoms were evaluated using the Ocular Surface Disease Index (OSDI). The association between OSDI, NITBUT and metabolic parameters relating to diabetes were evaluated using multiple linear regression. Main Outcome Measures: The associations between long‐term glycaemic control and NITBUT and OSDI scores. Results: Stepwise multiple linear regression analysis revealed glycated haemoglobin to be the only significant independent variable for NITBUT (R2 = 0.099, P = 0.014) and OSDI (R2 = 0.062, P = 0.044) after controlling for potential confounders. The age‐adjusted prevalence of DES was 20% (95% confidence interval: 11–30%) in the Chinese T2DM population. The odds of DES for increasing percentage of glycated haemoglobin was 1.49 (95% confidence interval: 1.03–2.17, P = 0.04). Conclusions and Relevance: Our findings highlight the importance of good glycaemic control as a modifiable risk factor for both dry eye symptoms and tear film instability in patients with T2DM. [ABSTRACT FROM AUTHOR]

The rising success of anti-vascular endothelial growth factor ( VEGF) therapies in ocular disease has stimulated the use of such treatments in the surgical management of pterygium. We reviewed the literature to better understand the safety and efficacy of the adjunctive role of anti- VEGF treatments for pterygium excision. Without surgery, anti- VEGF alone may favourably alter symptoms and vascularity, but does not cause pterygium regression. Some evidence supports the use of anti- VEGF as an adjuvant therapy to surgery, especially when using a higher dose and a more frequent dosing regimen. Overall, anti- VEGF is generally safe and well tolerated in patients with pterygium. Currently, the evidence does not conclusively support the use of anti- VEGF in pterygium surgery. However, further research may guide unanswered questions regarding the interaction between VEGF and other factors responsible for pterygium growth. In addition, the optimal route and dosage of anti- VEGF administration is not yet known. [ABSTRACT FROM AUTHOR]

With this issue we begin print publishing the responses received in our call for Medical Education Adaptations: Lessons learned from educators' experiences rapidly transforming practice on account of COVID‐19 related disruption. [ABSTRACT FROM AUTHOR]