The miR-183/96/182 cluster regulates sensory innervation, resident myeloid cells and functions of the cornea through cell type-specific target genes

The conserved miR-183/96/182 cluster (miR-183C) is expressed in both corneal resident myeloid cells (CRMCs) and sensory nerves (CSN) and modulates corneal immune/inflammatory responses. To uncover cell type-specific roles of miR-183C in CRMC and CSN and their contributions to corneal physiology, myeloid-specific miR-183C conditional knockout (MS-CKO), and sensory nerve-specific CKO (SNS-CKO) mice were produced and characterized in comparison to the conventional miR-183C KO. Immunofluorescence and confocal microscopy of flatmount corneas, corneal sensitivity, and tear volume assays were performed in young adult naïve mice; 3' RNA sequencing (Seq) and proteomics in the trigeminal ganglion (TG), cornea and CRMCs. Our results showed that, similar to conventional KO mice, the numbers of CRMCs were increased in both MS-CKO and SNS-CKO vs age- and sex-matched WT control littermates, suggesting intrinsic and extrinsic regulations of miR-183C on CRMCs. The number of CRMCs was increased in male vs female MS-CKO mice, suggesting sex-dependent regulation of miR-183C on CRMCs. In the miR-183C KO and SNS-CKO, but not the MS-CKO mice, CSN density was decreased in the epithelial layer of the cornea, but not the stromal layer. Functionally, corneal sensitivity and basal tear volume were reduced in the KO and SNS-CKO, but not the MS-CKO mice. Tear volume in males is consistently higher than female WT mice. Bioinformatic analyses of the transcriptomes revealed a series of cell-type specific target genes of miR-183C in TG sensory neurons and CRMCs. Our data elucidate that miR-183C imposes intrinsic and extrinsic regulation on the establishment and function of CSN and CRMCs by cell-specific target genes. miR-183C modulates corneal sensitivity and tear production through its regulation of corneal sensory innervation.

Prolonged facemask wearing among hospital workers and dry eye - a mixed-methods study

BACKGROUND

Prolonged facemask wearing may have negatively affected essential workers with dry eye. We conducted a mixed-methods study to examine and understand the associations of the ocular surface, periocular environment, and dry eye-related symptoms among hospital workers across the job spectrum with prolonged facemask use.

METHODS

We recruited clinical and non-clinical hospital workers with self-reported symptoms of dry eye and prolonged facemask use. We measured symptoms using the 5-item Dry Eye Questionnaire and the Ocular Surface Disease Index (OSDI). Objective ocular signs included corneal and conjunctival staining, fluorescein tear break up time (TBUT), meibography, tear film interferometry, and periocular humidity. We compared symptoms and signs across levels of periocular humidity, dry eye severity, facemask type, and job type. Participants with moderate or severe dry eye symptoms (OSDI > = 23) were invited for a semi-structured, one-on-one interview.

RESULTS

We enrolled 20 clinical and 21 non-clinical hospital workers: 27% were 40 years or older, 76% were female, 29% reported a race other than White, and 20% were Hispanic. Seventeen individuals participated in the semi-structured interviews. From the quantitative analyses, we found that 90% of participants reported worsened severity of dry eye at work due to facemasks. Although wearing facemasks resulted in higher periocular humidity levels compared with not wearing facemasks, 66% participants reported increased airflow over their eyes. Findings from the qualitative interviews supported the finding that use of facemasks worsened dry eye symptoms, especially when facemasks were not fitted around the nose. The data did not suggest that non-clinical hospital workers experienced a greater impact of dry eye than clinical workers.

CONCLUSIONS

Healthcare providers and patients with dry eye should be educated about the discomfort and the ocular surface health risks associated with inadequately fitted facemasks. Wearing a fitted facemask with a pliable nose wire appears to mitigate the upward airflow.

Effectiveness of interventions for dry eye: a protocol for an overview of systematic reviews

INTRODUCTION

Dry eye is a leading cause of ocular morbidity and economic and societal burden for patients and healthcare systems. There are several treatment options available for dry eye and high-quality systematic reviews synthesise the evidence for their effectiveness and potential harms.

METHODS AND ANALYSIS

We will search the Cochrane Eyes and Vision US satellite (CEV@US) database of eyes and vision systematic reviews for systematic reviews on interventions for dry eye. CEV@US conducted an initial search of PubMed and Embase to populate the CEV@US database of eyes and vision systematic reviews in 2007, which was updated most recently in August 2021. We will search the database for systematic reviews published since 1 January 2016 because systematic reviews more than 5 years are unlikely to be up to date. We will consider Cochrane and non-Cochrane systematic reviews eligible for inclusion. Two authors will independently screen articles. We will include studies that evaluate interventions for dry eye and/or meibomian gland dysfunction with no restriction on types of participants or review language. We will select reliable systematic reviews (ie, those meeting pre-established methodological criteria) for inclusion, assessed by one investigator and verified by a second investigator. We will extract ratings of the certainty of evidence from within each review. We will report the degree of overlap for systematic reviews that answer similar questions and include overlapping primary studies. We will present results of the overview in alignment with guidelines in the Cochrane Handbook of Systematic Reviews of Interventions (Online Chapter 5: Overviews of Reviews), the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, and an overview of reviews quality and transparency checklist. The anticipated start and completion dates for this overview are 1 May 2021 and 30 April 2022, respectively.

ETHICS AND DISSEMINATION

This overview will not require the approval of an Ethics Committee because it will use published studies. We will publish results in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42021279880.