COVID-19: Special Precautions in Ophthalmic Practice and FAQs on Personal Protection and Mask Selection.

The Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory coronavirus-2, was first reported in December 2019. The World Health Organization declared COVID-19 a pandemic on March 11, 2020 and as of April 17, 2020, 210 countries are affected with >2,000,000 infected and 140,000 deaths. The estimated case fatality rate is around 6.7%. We need to step up our infection control measures immediately or else it may be too late to contain or control the spread of COVID-19. In case of local outbreaks, the risk of infection to healthcare workers and patients is high. Ophthalmic practice carries some unique risks and therefore high vigilance and special precautions are needed. We share our protocols and experiences in the prevention of infection in the current COVID-19 outbreak and the previous severe acute respiratory syndrome epidemic in Hong Kong. We also endeavor to answer the key frequently asked questions in areas of the coronaviruses, COVID-19, disease transmission, personal protection, mask selection, and special measures in ophthalmic practices. COVID-19 is highly infectious and could be life-threatening. Using our protocol and measures, we have achieved zero infection in our ophthalmic practices in Hong Kong and China. Preventing spread of COVID-19 is possible and achievable.

Isoliquiritigenin from licorice root suppressed neovascularisation in experimental ocular angiogenesis models.

AIM: To explore the antiangiogenic property of isoliquiritigenin (ISL) on in vivo and in vitro models. DESIGN: Laboratory investigation. METHODS: The effect of ISL on angiogenesis development was investigated using ex ovo chick chorioallantoic membrane model. Its effect on pathological angiogenesis was examined by (1) silver nitrate cauterisation-induced corneal neovascularisation in BALB/c mice, followed by topical ISL (0.2-50 µM) and CD31 immunofluorescence of corneal blood vessels; (2) argon laser photocoagulation-induced choroidal neovascularisation in C57BL/6 mice, followed by intravitreal ISL (10-200 µM) and fundus fluorescein angiography and immunofluorescence with Griffonia simplicifolia isolectin-B4 (GSA I-B4); and (3) oxygen-induced retinopathy in C57BL/6J mice pups, followed by intravitreal ISL (1-100 µM) and GSA I-B4 immunofluorescence. The vascular area was quantified and analysed by one-way analysis of variance and Student t test. Expression of vascular endothelial growth factor (VEGF) and pigment-epithelium-derived factor in human umbilical vein endothelial cells was analysed by western blotting. RESULTS: Ex ovo chick chorioallantoic membrane assay showed that ISL dose-dependently suppressed VEGF-induced vessel growth. In vivo experiments illustrated that topical ISL alleviated corneal neovascularisation (IC(50)=7.14 µM, day 7) and intravitreal ISL reduced vessel leakage and GSA I-B4-positive vascular area in choroidal and retinal neovascularisation. ISL was found to dose-dependently suppress VEGF and induce pigment epithelium derived factor expression in cultured endothelial cells. CONCLUSION: Using various experimental models of ocular neovascularisation, the authors have demonstrated that ISL from licorice extract has an antiangiogenic effect. The authors' findings suggest that ISL may be a potential antiangiogenic molecule in the development of therapy for neovascularisation diseases.