Cataract Surgery Trends during Lockdown and Unlocking Periods of COVID-19 Pandemic: A Cross-sectional Hospital-based Study

Introduction: Coronavirus Disease-2019 (COVID-19) has affected healthcare access to population around the world. India also had its own set of problems for patients with disruption of healthcare services during the pandemic. This also brought in unique challenges for ophthalmologists who adapted to new challenges to provide quality care to the patients including those reporting for cataract surgery. Aim: To find out cataract surgery trends and demographic variables during lockdown and unlocking periods of COVID-19 pandemic. Materials and Methods: This cross-sectional hospital-based study was conducted at Ophthalmology department of a tertiary care centre in eastern India, from January 2020 to March 2022. Trends of cataract surgery including numbers, demographic factors, visual acuity at presentation, difference during first and second lock and unlock periods etc were compared during various lock and unlock period over more than two years. Results: A total of 3,843 patients were planned for surgery and 3,594 patients underwent cataract surgery. A total of 218 patients reported being positive for COVID-19 preoperatively and voluntarily dropped out from surgery. A total of 24 patients were found to be positive during preoperative Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) workup and were excluded from surgery. Seven patients didn't report for the surgery. A total of 59 patients reported febrile illness during one month postoperative period. There was dip in cataract surgery during lockdown periods (from 178.33 every month in pre COVID-19 period to near zero during first lockdown period) but recovery was much faster during second unlock period compared to first unlock period. Conclusion: The study concludes that there was drastic decrease in number of patients undergoing cataract surgery during COVID-19 pandemic. Predominantly young, male patients who had advanced morphology of cataracts with poor visual acuity accessed healthcare set-up for cataract surgery during initial lock and unlock period. Similar trend was seen during second lock and unlock period with rapid recovery of numbers and demography of cataract surgery patients to pre-COVID-19 levels. [ FROM AUTHOR] Copyright of Journal of Clinical & Diagnostic Research is the property of JCDR Research & Publications Private Limited and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Outcome of COVID-19-Associated Acute Stroke: A Study from South India.

Background and Objective: Coronavirus 2019 (COVID-19) infection is prevalent worldwide. COVID-19 infection can lead to various neurological disorders including acute stroke. We investigated the functional outcome and its determinants among our patients with acute stroke associated with COVID-19 infection in the present setup. Materials and Methods: This study is a prospective study in which we recruited acute stroke patients with COVID-19 positivity. Data on duration of COVID-19 symptoms and type of acute stroke were recorded. All patients underwent stroke subtype workup and measurement of D-dimer, C-reactive protein (CRP), lactate-dehydrogenase (LDH), procalcitonin, interleukin-6, and ferritin levels. Poor functional outcome was defined by modified Rankin score (mRS) ≥3 at 90 days. Results: During the study period, 610 patients were admitted for acute stroke, of whom 110 (18%) tested positive for COVID-19 infection. Majority (72.7%) were men with a mean age of 56.5 years and mean duration of COVID-19 symptoms for 6.9 days. Acute ischemic and hemorrhagic strokes were observed in 85.5% and 14.5% patients, respectively. Poor outcome was observed in 52.7%, including in-hospital mortality in 24.5% patients. COVID-19 symptoms ≤5 days (odds ratio [OR]: 1.41, 95% confidence interval [CI]: 1.20-2.99), CRP positivity (OR: 1.97, 95% CI: 1.41-4.87), elevated levels of D-dimer (OR: 2.11, 95% CI: 1.51-5.61), interleukin-6 (OR: 1.92, 95% CI: 1.04-4.74), and serum ferritin (OR: 2.4, 95% CI: 1.02-6.07), and cycle threshold (Ct) value ≤25 (OR: 8.8, 95% CI: 6.52-12.21) were independent predictors of poor outcome. Conclusion: Poor outcomes were relatively higher among acute stroke patients with concomitant COVID-19 infection. In the present study, we established the independent predictors of poor outcome to be onset of COVID-19 symptoms (<5 days) and elevated levels of CRP, D-dimer, interleukin-6, ferritin, and Ct value ≤25 in acute stroke.

Impact of ICT-Enabled Teaching-Learning Processes in Physical Sciences in Indian Higher Education in Light of COVID-19: A Comprehensive Overview.

The COVID-19 (coronavirus disease) pandemic has caused a lot of damage to the social, economic and educational infrastructure of the world. The rapid change in the online learning environment calls for the development of effective learning strategies to support student learning. Principally information communication technology (ICT) emerged as a new hope in teaching-learning in streams like science and technology. Especially in the teaching-learning of a challenging subject like physics and its various streams, e.g. mechanics, wave, optics, etc., the use of ICT has increased exponentially due to its unique properties. However, some of its side effects have also been visible during this period. This study presents the feedback, experiences and recommendations of physics teachers regarding the application of ICT in the teaching-learning of physics. This article offers a comprehensive view of the impact of information and communication technology-enabled teaching-learning processes in physical sciences. To accomplish this study, an 18-question questionnaire was circulated among physics teachers across the nation and more than 100 physics teachers participated and recorded their responses. The outcomes of these responses were analysed, and corresponding conclusions with recommendations are presented. This study may be helpful for students, teachers, researchers and policymakers working in this field of ICT-enabled physics education.

Recent development and challenges in the Indian economy

The study has been carried out with particular reference to hotel industry in Uttarakhand during Covid and its impact on state's economy. The hotel industry of Uttarakhand seeks discernible attention as the state itself offers limitless opportunities for tourism and adventure tourism. However, the pandemic posed unusual circumstances on various industries of Indian Economy including the hotel and tourism industry. The government and the hotel operators can collectively uplift the tourism and hospitality sector of Uttarakhand. The present paper is an attempt to throw light upon various new aspects of tour and travel industry i.e., Reverse Migration, Work from hills culture and Revenge Tourism which are being helpful in elevating the state's economy. The paper has also explored the concept of green hotels and hidden treasures of Uttarakhand. In addition, the recovery for hotel and tourism industry is a bit difficult, therefore, the state government needs to take some constructive measures. The paper suggests the need for polishing and refining the hospitality standards and services to deliver best of experience to the tourists, which will eventually increase their visit to Uttarakhand and hence uplift the economy.

Dry eye disease survey among schoolteachers and children using visual display terminals during COVID-19 lockdown-CODE study ( Co vid and d ry e ye study).

Background: Lockdown during COVID-19 led to teachers and children shifting to online classes, using visual display terminals (VDTs) for education, resulting in increased screen time. The present study was done to assess and understand the nature and magnitude of the problem and to suggest preventive or remedial measures. Methods: A questionnaire-based cross-sectional study was conducted. The questionnaire was prepared for an online survey (using Google Forms) and circulated among school children belonging to different schools across India using multiple groups on social media. Results: A total of 3327 participants from 46 schools across India participated in the survey. We found a marked rise in cumulative screen time for both teachers and students before and during the lockdown. There was a threefold increase in the number of participants with a cumulative screen time 6 h or more compared to the pre-COVID era. Teachers (older participants) had worse symptom scores than students. Larger screens, like televisions, were better VDTs compared to smartphones, tablets, or laptops. Conclusions: School administrators and policymakers should pay due attention to institutionalizing the guidelines about class duration, appropriate screens, and stipulating break duration during online classes, which will continue to remain the predominant mode of education for teachers and students alike, at least in the near future.

Investigating Psychological Differences Between Nurses and Other Health Care Workers From the Asia-Pacific Region During the Early Phase of COVID-19: Machine Learning Approach.

BACKGROUND: As the COVID-19 pandemic evolves, challenges in frontline work continue to impose a significant psychological impact on nurses. However, there is a lack of data on how nurses fared compared to other health care workers in the Asia-Pacific region. OBJECTIVE: This study aims to investigate (1) the psychological outcome characteristics of nurses in different Asia-Pacific countries and (2) psychological differences between nurses, doctors, and nonmedical health care workers. METHODS: Exploratory data analysis and visualization were conducted on the data collected through surveys. A machine learning modeling approach was adopted to further discern the key psychological characteristics differentiating nurses from other health care workers. Decision tree-based machine learning models (Light Gradient Boosting Machine, GradientBoost, and RandomForest) were built to predict whether a set of psychological distress characteristics (ie, depression, anxiety, stress, intrusion, avoidance, and hyperarousal) belong to a nurse. Shapley Additive Explanation (SHAP) values were extracted to identify the prominent characteristics of each of these models. The common prominent characteristic among these models is akin to the most distinctive psychological characteristic that differentiates nurses from other health care workers. RESULTS: Nurses had relatively higher percentages of having normal or unchanged psychological distress symptoms relative to other health care workers (n=233-260 [86.0%-95.9%] vs n=187-199 [74.8%-91.7%]). Among those without psychological symptoms, nurses constituted a higher proportion than doctors and nonmedical health care workers (n=194 [40.2%], n=142 [29.5%], and n=146 [30.3%], respectively). Nurses in Vietnam showed the highest level of depression, stress, intrusion, avoidance, and hyperarousal symptoms compared to those in Singapore, Malaysia, and Indonesia. Nurses in Singapore had the highest level of anxiety. In addition, nurses had the lowest level of stress, which is the most distinctive psychological outcome characteristic derived from machine learning models, compared to other health care workers. Data for India were excluded from the analysis due to the differing psychological response pattern observed in nurses in India. A large number of female nurses emigrating from South India could not have psychologically coped well without the support from family members while living alone in other states. CONCLUSIONS: Nurses were least psychologically affected compared to doctors and other health care workers. Different contexts, cultures, and points in the pandemic curve may have contributed to differing patterns of psychological outcomes amongst nurses in various Asia-Pacific countries. It is important that all health care workers practice self-care and render peer support to bolster psychological resilience for effective coping. In addition, this study also demonstrated the potential use of decision tree-based machine learning models and SHAP value plots in identifying contributing factors of sophisticated problems in the health care industry.

Lockdown imposition due to COVID-19 and its effect on orthopedic emergency department in level 1 trauma center in South Asia.

Background: The coronavirus pandemic brought the entire world to a standstill. One of the most stringent lockdowns in the world was implemented in India. With the entire healthcare system being stretched, emergency orthopaedic services also take a hit. We studied the trends in patient presentation, testing, management, and restructuring of doctors at a tertiary care orthopaedic centre and compared them with the data from the same time period the previous year (2019). Method: Data was collected separately for all the 5 different phases of lockdown and unlock, as well as for the same duration of months in 2019, and was analysed for epidemiological trends. Results: A rapid fall in the total number of cases was seen during the lockdown, followed by a skewed rise during the unlock. Forearm, wrist, and hip fractures were the most common fractures. Once nucleic acid testing of all patients intended to be admitted was started, a steep rise in coronavirus positivity was seen. There was a reduction in the total number of cases compared to 2019, but it was not as significant as would have been expected due to the complete standstill of activity during the lockdown. Conclusion: During a pandemic, with the healthcare system under a crisis of workforce and infrastructure, there needs to be a separate task force for catering to orthopaedic emergencies since all fractures cannot be managed conservatively and the numbers of trauma-related patients did not show a stark fall as compared to normal months of last year. Level of evidence: Level 3 Retrospective Case Series.

COVID-19 Vaccine-Induced Immune Thrombotic Thrombocytopenia (VITT) and Cerebral Venous Sinus Thrombosis (CVST)- Lessons for India.

The COVID-19 pandemic evolved rapidly, overwhelming health care systems around the world. The cost to life and socioeconomic burden prompted a search for new treatments and vaccines. Several collaborations developed and could deliver state-of-the-art vaccines with acceptable efficacy and safety in record time. Recently, vaccination with Oxford-AstraZeneca and Johnson and Johnson vaccines was halted due to the reported adverse effects of vaccine-induced immune thrombotic thrombocytopenia (VITT) and cerebral venous sinus thrombosis (CVST). Although a detailed risk-benefit analysis led to their reinstitution, physicians across the world are still trying to understand the pathophysiology and mechanisms of these neurological adverse effects in order to better identify, diagnose, and treat them. One of the mechanisms that have been implicated is related to the adenovirus-based vector of these vaccines. COVISHIELD, which is the most widely administered vaccine in India, also shares the same vector. As India enters the next phase of vaccine distribution for younger adults, there are chances that such adverse effects may emerge. In this review, we analyze the temporary suspension of the administration of the vaccines due to VITT/CVST, summarize the existing guidelines about diagnosis and treatment of these neurological disorders as well as the need for increasing pharmacovigilance and awareness among physicians. Screening for potential risk factors, avoiding aggravating factors like dehydration, and providing choices in vaccinating the high-risk populations could help in avoiding these rare but potentially fatal adverse outcome.

A longitudinal study on the mental health of general population during the COVID-19 epidemic in China.

In addition to being a public physical health emergency, Coronavirus disease 2019 (COVID-19) affected global mental health, as evidenced by panic-buying worldwide as cases soared. Little is known about changes in levels of psychological impact, stress, anxiety and depression during this pandemic. This longitudinal study surveyed the general population twice - during the initial outbreak, and the epidemic's peak four weeks later, surveying demographics, symptoms, knowledge, concerns, and precautionary measures against COVID-19. There were 1738 respondents from 190 Chinese cities (1210 first-survey respondents, 861 s-survey respondents; 333 respondents participated in both). Psychological impact and mental health status were assessed by the Impact of Event Scale-Revised (IES-R) and the Depression, Anxiety and Stress Scale (DASS-21), respectively. IES-R measures PTSD symptoms in survivorship after an event. DASS -21 is based on tripartite model of psychopathology that comprise a general distress construct with distinct characteristics. This study found that there was a statistically significant longitudinal reduction in mean IES-R scores (from 32.98 to 30.76, p < 0.01) after 4 weeks. Nevertheless, the mean IES-R score of the first- and second-survey respondents were above the cut-off scores (>24) for PTSD symptoms, suggesting that the reduction in scores was not clinically significant. During the initial evaluation, moderate-to-severe stress, anxiety and depression were noted in 8.1%, 28.8% and 16.5%, respectively and there were no significant longitudinal changes in stress, anxiety and depression levels (p > 0.05). Protective factors included high level of confidence in doctors, perceived survival likelihood and low risk of contracting COVID-19, satisfaction with health information, personal precautionary measures. As countries around the world brace for an escalation in cases, Governments should focus on effective methods of disseminating unbiased COVID-19 knowledge, teaching correct containment methods, ensuring availability of essential services/commodities, and providing sufficient financial support.

Safety attitudes, burnout and wellbeing among healthcare workers during the COVID-19 pandemic: an Indo-Pacific regional cross-sectional study.

INTRODUCTION: The COVID-19 pandemic has had an unprecedented impact in Asia and has placed significant burden on already stretched healthcare systems. We examined the impact of COVID-19 on safety attitudes among healthcare workers (HCWs) as well as their associated demographic and occupational factors, and measures of burnout, depression and anxiety. METHODS: A cross-sectional survey study utilising snowball sampling was performed involving doctors, nurses and allied health professions from 23 hospitals in Singapore, Malaysia, India and Indonesia between 29 May 2020 and 13 July 2020. This survey collated demographic data and workplace conditions and included three validated questionnaires: Safety Attitudes Questionnaire (SAQ); Oldenburg Burnout Inventory; and Hospital and Anxiety Depression Scale. We performed multivariate mixed model regression to assess for independent associations with the SAQ Total Percentage Agree Rates (PAR). RESULTS: We obtained 3,163 responses. A SAQ Total PAR of 35.7%, 15.0%, 51.0% and 3.3% was calculated among respondents from Singapore, Malaysia, India and Indonesia, respectively. Burnout scores were highest among respondents from Indonesia and lowest in respondents from India at 70.9%-85.4% versus 56.3%-63.6%, respectively. Multivariate analyses revealed that meeting burnout and depression thresholds, and shifts lasting ≥ 12 hours were significantly associated with lower SAQ Total PAR. CONCLUSION: Addressing factors contributing to high burnout and depression, and placing strict limits on work hours per shift may contribute significantly towards improving safety culture among HCWs and should remain priorities as this pandemic continues.

Has the time to reinstate elective orthopedic procedures come?

BACKGROUND: The coronavirus pandemic changed how we manage and operate patients in orthopaedic practice. Although elective orthopaedic procedures were halted to prevent spread of the disease as well as sustain supplies of essential protective equipment and healthcare workers, trauma services were continued. We studied the orthopaedic trauma cases operated over 6 months of the pandemic, and discuss the protocols used to minimize disease spread. METHODS: Data was collected for all orthopaedic emergency cases operated at our centre from 1 st March - 10 th August 2020. During this time specific protocols were used for first aid, pre-operative care, inside the operation theatre, post-operative stay as well as for follow ups. RESULTS: A total of 851 patients were operated. A sharp decline in surgeries was seen during the lockdown. Average stay in the hospital was 4 days. Only 44% of the patients came for follow-up visits. None of the contacted patients or their relatives developed symptoms or tested positive for COVID after discharge. CONCLUSION: Multiple waves and various mutant strains of COVID-19 have made this pandemic longer than expected. Elective orthopaedic cases cannot be ignored for forever, as it leads to poor quality of life and an increasing burden of such patients. We suggest, that using the protocols used at our centre, we have successfully operated on cases without risking spread of the virus. Thus, we believe it's time to reinstate elective orthopaedic procedures, in a phased manner.

Attitudes toward COVID-19 vaccination and willingness to pay: comparison of people with and without mental disorders in China.

BACKGROUND: Acceptance and willingness to pay for the COVID-19 vaccine are unknown. AIMS: We compared attitudes toward COVID-19 vaccination in people suffering from depression or anxiety disorder and people without mental disorders, and their willingness to pay for it. METHOD: Adults with depression or anxiety disorder (n = 79) and healthy controls (n = 134) living in Chongqing, China, completed a cross-sectional study between 13 and 26 January 2021. We used a validated survey to assess eight aspects related to attitudes toward the COVID-19 vaccines. Psychiatric symptoms were assessed by the 21-item Depression, Anxiety and Stress Scale. RESULTS: Seventy-six people with depression or anxiety disorder (96.2%) and 134 healthy controls (100%) reported willingness to receive the COVID-19 vaccine. A significantly higher proportion of people with depression or anxiety disorder (64.5%) were more willing to pay for the COVID-19 vaccine than healthy controls (38.1%) (P ≤ 0.001). After multivariate adjustment, severity of depression and anxiety was significantly associated with willingness to pay for COVID-19 vaccination among psychiatric patients (P = 0.048). Non-healthcare workers (P = 0.039), health insurance (P = 0.003), living with children (P = 0.006) and internalised stigma (P = 0.002) were significant factors associated with willingness to pay for COVID-19 vaccine in healthy controls. CONCLUSIONS: To conclude, psychiatric patients in Chongqing, China, showed high acceptance and willingness to pay for the COVID-19 vaccine. Factors associated with willingness to pay for the COVID-19 vaccine differed between psychiatric patients and healthy controls.

Changes in Stroke Hospital Care During the COVID-19 Pandemic: A Systematic Review and Meta-Analysis.

[Figure: see text].

Comparison of Brain Activation Patterns during Olfactory Stimuli between Recovered COVID-19 Patients and Healthy Controls: A Functional Near-Infrared Spectroscopy (fNIRS) Study.

Impaired sense of smell occurs in a fraction of patients with COVID-19 infection, but its effect on cerebral activity is unknown. Thus, this case report investigated the effect of COVID-19 infection on frontotemporal cortex activity during olfactory stimuli. In this preliminary study, patients who recovered from COVID-19 infection (n = 6) and healthy controls who never contracted COVID-19 (n = 6) were recruited. Relative changes in frontotemporal cortex oxy-hemoglobin during olfactory stimuli was acquired using functional near-infrared spectroscopy (fNIRS). The area under curve (AUC) of oxy-hemoglobin for the time interval 5 s before and 15 s after olfactory stimuli was derived. In addition, olfactory function was assessed using the Sniffin' Sticks 12-identification test (SIT-12). Patients had lower SIT-12 scores than healthy controls (p = 0.026), but there were no differences in oxy-hemoglobin AUC between healthy controls and patients (p > 0.05). This suggests that past COVID-19 infection may not affect frontotemporal cortex function, and these preliminary results need to be verified in larger samples.

Mucormycosis and COVID-19: An epidemic within a pandemic in India.

IMPORTANCE: Coronavirus disease (COVID-19) causes an immunosuppressed state and increases risk of secondary infections like mucormycosis. We evaluated clinical features, predisposing factors, diagnosis and outcomes for mucormycosis among patients with COVID-19 infection. METHODS: This prospective, observational, multi-centre study included 47 consecutive patients with mucormycosis, diagnosed during their course of COVID-19 illness, between January 3 and March 27, 2021. Data regarding demography, underlying medical conditions, COVID-19 illness and treatment were collected. Clinical presentations of mucormycosis, imaging and biochemical characteristics and outcome were recorded. RESULTS: Of the 2567 COVID-19 patients admitted to 3 tertiary centres, 47 (1.8%) were diagnosed with mucormycosis. Mean age was 55 ± 12.8years, and majority suffered from diabetes mellitus (n = 36, 76.6%). Most were not COVID-19 vaccinated (n = 31, 66.0%) and majority (n = 43, 91.5%) had developed moderate-to-severe pneumonia, while 20 (42.6%) required invasive ventilation. All patients had received corticosteroids and broad-spectrum antibiotics while most (n = 37, 78.7%) received at least one anti-viral medication. Mean time elapsed from COVID-19 diagnosis to mucormycosis was 12.1 ± 4.6days. Eleven (23.4%) subjects succumbed to their disease, mostly (n = 8, 72.7%) within 7 days of diagnosis. Among the patients who died, 10 (90.9%) had pre-existing diabetes mellitus, only 2 (18.2%) had received just one vaccine dose and all developed moderate-to-severe pneumonia, requiring oxygen supplementation and mechanical ventilation. CONCLUSIONS: Mucormycosis can occur among COVID-19 patients, especially with poor glycaemic control, widespread and injudicious use of corticosteroids and broad-spectrum antibiotics, and invasive ventilation. Owing to the high mortality, high index of suspicion is required to ensure timely diagnosis and appropriate treatment in high-risk populations.

An Asia-Pacific study on healthcare workers' perceptions of, and willingness to receive, the COVID-19 vaccination.

OBJECTIVE: In the fight against COVID-19, vaccination is vital in achieving herd immunity. Many Asian countries are starting to vaccinate frontline workers; however, expedited vaccine development has led to hesitancy among the general population. We evaluated the willingness of healthcare workers to receive the COVID-19 vaccine. METHODS: From 12 to 21 December 2020, we recruited 1720 healthcare workers from 6 countries: China, India, Indonesia, Singapore, Vietnam and Bhutan. The self-administrated survey collected information on willingness to vaccinate, perception of COVID-19, vaccine concerns, COVID-19 risk profile, stigma, pro-socialness scale, and trust in health authorities. RESULTS: More than 95% of the healthcare workers surveyed were willing to vaccinate. These respondents were more likely to perceive the pandemic as severe, consider the vaccine safe, have less financial concerns, less stigmatization regarding the vaccine, higher pro-socialness mindset and trust in health authorities. A high perceived pandemic risk index, low vaccine harm index and high pro-socialness index were independent predictors in multivariable analysis. CONCLUSIONS: The majority of healthcare workers in Asia are willing to receive COVID-19 vaccination. Perceived COVID-19 susceptibility, low potential risk of vaccine harm and pro-socialness are the main drivers. These findings may help formulate vaccination strategies in other countries.

Headache Related to PPE Use during the COVID-19 Pandemic.

PURPOSE OF REVIEW: Personal protection equipment (PPE)-associated headache is an unusual secondary headache disorder that predominantly occurs in healthcare workers as a consequence of the donning of protective respirators, face masks and/or eyewear. The appreciation of this entity is important given the significant ramifications upon the occupational health of healthcare workers and could additionally have an impact on persons living with pre-existing headache disorder(s). RECENT FINDINGS: There has been a renewed interest and recognition of PPE-associated headaches amongst healthcare professionals, largely brought about by the ongoing COVID-19 pandemic which has besieged healthcare systems worldwide. De novo PPE-associated headaches may present with migrainous or tension-type features and can be viewed as a subtype of external compression headache. The prognosis of the disorder is generally favourable, given that most headaches are short-lived without long-term sequalae. Several aetiologies have been postulated to account for the development of these headaches. Notably, these headaches can affect the occupational health and work performance of healthcare workers. In this review, we discuss the epidemiology, clinical characteristics, probable etiopathogenesis, management and prognosis of PPE-associated headaches in the context of the COVID-19 pandemic. Future directions for research and PPE development are proposed.

On‐Chip Mercury‐Free Deep‐UV Light‐Emitting Sources with Ultrahigh Germicidal Efficiency

In the current COVID‐19 scenario, there is an urgent need for developing efficient and mercury‐free deep‐ultraviolet (deep‐UV) light sources for disinfection applications. AlGaN‐based light‐emitting diodes (LEDs) may be considered as an alternative, but due to their inherent low efficiencies in the deep‐UV spectral region, significant developments are required to address efficiency issues. Here, a mercury‐free chip‐size deep‐UV light source is shown which is enabled by high‐vacuum chip‐scale cavity sealing overcoming the limitations of both mercury lamps and deep‐UV LEDs. These deep‐UV chips are cathodoluminescence based, in which a cavity is created with high vacuum integrity for efficient field‐emission. These chips demonstrate optical output power ≥20 mW (efficiency ≈4%) and, owing to the spectral overlap of phosphor cathodoluminescence spectra and germicidal effectiveness curve, resulted in log 6 (99.9999%) germicidal efficiency. Additionally, these chips offer high reliability, “instant” ON/OFF capability, high operational lifetimes, and low‐temperature dependence with complete design freedom. [ABSTRACT FROM AUTHOR] Copyright of Advanced Optical Materials is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)