Microbial Keratitis Before, During and After the COVID-19 Pandemic, and the Role of Contact Lens Wear and Hand Hygiene

Anna C Randag,1,2 Liesbeth Wellens,1 Nelly Kazemian,1 Barbara Schimmer,3 Jeroen van Rooij1,2 1Department of Cornea and Anterior Segment Disease, Rotterdam Eye Hospital, Rotterdam, The Netherlands; 2Rotterdam Ophthalmic Institute, Rotterdam, the Netherlands; 3Center for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The NetherlandsCorrespondence: Anna C Randag, Rotterdam Ophthalmic Institute, Schiedamse Vest 160, 3011 BH Rotterdam, The Netherlands, Email [email protected]: During the COVID-19 pandemic, there was a significant decline in the number of patients with both non-urgent and urgent ophthalmologic conditions presenting to emergency departments, leading to concerns about the whereabouts of patients in need of care. We hypothesized that there was an actual decrease in microbial keratitis (MK) cases, due to reduced contact lens (CL) wear and improved hand hygiene, including alcohol-based hand disinfection. Besides, we questioned if non-pharmaceutical interventions would have a sustained effect after the COVID-19 pandemic.Methods: Retrospectively, characteristics of patients presenting with MK at a large ophthalmic tertiary referral center were compared during 9 March– 15 June of 2018 and 2019 (“pre-COVID”), 2020 (“COVID”) and 2022 and 2023 (“post-COVID”). In an online cross-sectional survey among CL wearers, CL wear and hand hygiene habits were compared for the recall months February and April 2020.Results: Three hundred and one MK patients were included: 79 in 2018, 69 in 2019, 41 in 2020, 60 in 2022 and 52 in 2023. Presentation delay was ≥ 4 days in 38% during COVID, compared to 54% pre-COVID (p = 0.106). The proportion of CL related MK did not differ (p = 0.704). Fewer patients were admitted than pre-COVID (p = 0.026), without a difference in admission indications (p = 0.322). Pseudomonas aeruginosa and Staphylococcus aureus cases were not observed during COVID. Post-COVID, MK by Pseudomonas aeruginosa occurred more often than pre-COVID (p < 0.001). In the online survey with 791 respondents, hand washing before CL insertion and removal and hand disinfection were reported more often in April 2020 than February 2020 (respectively, p = 0.001, p < 0.001 and p < 0.001).Conclusion: We found no evidence of MK patients facing barriers to accessing hospital care during the COVID-19 pandemic, as presentation delays were not longer and cases not more severe. Our data suggest that a decreased MK incidence may be due to improved hand hygiene practices, including alcohol-based hand disinfection.Keywords: microbial keratitis, COVID-19, lockdown, hospital admissions, hand disinfection, pseudomonas aeruginosa