Asymptomatic neonatal herpes simplex virus infection in mice leads to long-term cognitive impairment

Neonatal herpes simplex virus (nHSV) is a devastating infection impacting approximately 14,000 newborns globally each year. Infection is associated with high neurologic morbidity and mortality, making early intervention and treatment critical. Clinical outcomes of symptomatic nHSV infections are well-studied, but little is known about the frequency of, or outcomes following, sub-clinical or asymptomatic nHSV. Given the ubiquitous nature of HSV infection and frequency of asymptomatic shedding in adults, subclinical infections are underreported, yet could contribute to long-term neurological damage. To assess potential neurological morbidity associated with subclinical nHSV infection, we developed a low-dose (100 PFU) HSV infection protocol in neonatal C57BL/6 mice. At this dose, HSV DNA was detected in the brain by PCR but was not associated with acute clinical symptoms. However, months after initial inoculation with 100 PFU of HSV, we observed impaired mouse performance on a range of cognitive and memory performance tasks. Memory impairment was induced by infection with either HSV-1 or HSV-2 wild-type viruses, but not by a viral mutant lacking the autophagy-modulating Beclin-binding domain of the neurovirulence gene γ34.5. Retroviral expression of wild type γ34.5 gene led to behavioral pathology in mice, suggesting that γ34.5 expression may be sufficient to cause cognitive impairment. Maternal immunization and HSV-specific antibody treatment prevented offspring from developing neurological sequelae following nHSV-1 infection. Altogether, these results support the idea that subclinical neonatal infections may lead to cognitive decline in adulthood, with possible profound implications for research on human neurodegenerative disorders such as Alzheimer's Disease.

Survey of rectal cancer MRI technique and reporting tumour descriptors in the UK: a multi-centre British Society of Gastrointestinal and Abdominal Radiology (BSGAR) audit

AIM

To evaluate variation in magnetic resonance imaging (MRI) technique and reporting of rectal cancer staging examinations across the UK.

MATERIALS AND METHODS

A retrospective, multi-centre audit was undertaken of imaging protocols and information documented within consecutive MRI rectal cancer reports between March 2020 and August 2021, which were compared against American and European guidelines. Inclusion criteria included histologically proven rectal adenocarcinoma and baseline staging MRI rectum only.

RESULTS

Fully anonymised data from 924 MRI reports by 78 radiologists at 24 centres were evaluated. Thirty-two per cent of radiologists used template reporting, but these reports offered superior documentation of 13 out of 18 key tumour features compared to free-text reports including T-stage, relation to peritoneal reflection and mesorectal fascia (MRF), nodal status, and presence of extramural venous invasion (EMVI; p<0.027 in each). There was no significant differences in the remaining five features. Across all tumour locations, the tumour relationship to the MRF, the presence of EMVI, and the presence of tumour deposits were reported in 79.5%, 85.6%, and 44% of cases, respectively, and tumour, nodal, and distant metastatic stage documented in 94.4%, 97.7%, and 78.3%. In low rectal tumours, the relationship to the anal sphincter complex was reported in only 54.6%.

CONCLUSION

Considerable variation exists in rectal cancer MRI acquisition and reporting in this sample of UK centres. Inclusion of key radiological features in reports must be improved for risk stratification and treatment decisions. Template reporting is superior to free-text reporting. Routine adoption of standardised radiology practices should now be considered to improve standards to facilitate personalised precision treatment for patients to improve outcomes.

METRIC-EF: magnetic resonance enterography to predict disabling disease in newly diagnosed Crohn's disease-protocol for a multicentre, non-randomised, single-arm, prospective study

INTRODUCTION

Crohn's disease (CD) is characterised by discontinuous, relapsing enteric inflammation. Instituting advanced therapies at an early stage to suppress inflammation aims to prevent future complications such as stricturing or penetrating disease, and subsequent surgical resection. Therapeutics are effective but associated with certain side-effects and relatively expensive. There is therefore an urgent need for robust methods to predict which newly diagnosed patients will develop disabling disease, to identify patients who are most likely to benefit from early, advanced therapies. We aim to determine if magnetic resonance enterography (MRE) features at diagnosis improve prediction of disabling CD within 5 years of diagnosis.

METHODS AND ANALYSIS

We describe the protocol for a multicentre, non-randomised, single-arm, prospective study of adult patients with newly diagnosed CD. We will use patients already recruited to the METRIC study and extend their clinical follow-up, as well as a separate group of newly diagnosed patients who were not part of the METRIC trial (MRE within 3 months of diagnosis), to ensure an adequate sample size. Follow-up will extend for at least 4 years. The primary outcome is to evaluate the comparative predictive ability of prognostic models incorporating MRE severity scores (Magnetic resonance Enterography Global Score (MEGS), simplified MAgnetic Resonance Index of Activity (sMaRIA) and Lémann Index) versus models using standard characteristics alone to predict disabling CD (modified Beaugerie definition) within 5 years of new diagnosis.

ETHICS AND DISSEMINATION

This study protocol achieved National Health Service Research Ethics Committee (NHS REC), London-Hampstead Research Ethics Committee approval (IRAS 217422). Our findings will be disseminated via conference presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ISRCTN76899103.

Imaging features for the prediction of clinical endpoints in chronic liver disease: a scoping review protocol

INTRODUCTION

Chronic liver disease is a growing cause of morbidity and mortality in the UK. Acute presentation with advanced disease is common and prioritisation of resources to those at highest risk at earlier disease stages is essential to improving patient outcomes. Existing prognostic tools are of limited accuracy and to date no imaging-based tools are used in clinical practice, despite multiple anatomical imaging features that worsen with disease severity.In this paper, we outline our scoping review protocol that aims to provide an overview of existing prognostic factors and models that link anatomical imaging features with clinical endpoints in chronic liver disease. This will provide a summary of the number, type and methods used by existing imaging feature-based prognostic studies and indicate if there are sufficient studies to justify future systematic reviews.

METHODS AND ANALYSIS

The protocol was developed in accordance with existing scoping review guidelines. Searches of MEDLINE and Embase will be conducted using titles, abstracts and Medical Subject Headings restricted to publications after 1980 to ensure imaging method relevance on OvidSP. Initial screening will be undertaken by two independent reviewers. Full-text data extraction will be undertaken by three pretrained reviewers who have participated in a group data extraction session to ensure reviewer consensus and reduce inter-rater variability. Where needed, data extraction queries will be resolved by reviewer team discussion. Reporting of results will be based on grouping of related factors and their cumulative frequencies. Prognostic anatomical imaging features and clinical endpoints will be reported using descriptive statistics to summarise the number of studies, study characteristics and the statistical methods used.

ETHICS AND DISSEMINATION

Ethical approval is not required as this study is based on previously published work. Findings will be disseminated by peer-reviewed publication and/or conference presentations.

A122 WATER EXCHANGE FACILITATES HIGH CECAL INTUBATION RATE FOLLOWING INCOMPLETE COLONOSCOPY

Background

Incomplete colonoscopy is a complex problem that negatively affects the success of colon cancer screening programs. Failure to intubate the cecum is associated with a significant risk of missed colorectal cancer and increases costs through missed diagnoses and salvage investigations. Water exchange (WE) colonoscopy is associated with a high rate of patient comfort and cecal intubation (CI) and may be of value in preventing and following up on incomplete colonoscopy.

Aims

To estimate effectiveness of WE colonoscopy as initial salvage of incomplete colonoscopy.

Methods

All patients referred to the Kelowna Gastroenterology group for incomplete colonoscopy between Jan 2010 to Dec 2019 were included. Demographic, clinical, procedural, and pathological information were collected via retrospective chart review. Patients underwent WE colonoscopy by a single endoscopist. The outcomes evaluated were CI rate, sedation requirements, and adenoma detection.

Results

116 patients met study criteria and underwent WE colonoscopy after a previously failed or incomplete colonoscopy for technical reasons. The mean age was 66 years (range 21–89). 83 (72%) patients were female. 53 (46%) patients had previous abdominal surgery, and 42 (36%) had previous pelvic surgery. 65 (56%) patients had previous bowel disease. 81 (70%) patients had previously incomplete conventional air insufflation (AI) colonoscopy, 9 (8%) patients had previously incomplete WE colonoscopy, and 5 (4%) patients underwent unsuccessful combination of WE and AI colonoscopy. 17 (15%) patients had previously incomplete flexible sigmoidoscopy, and 4 (3%) patients had previously incomplete water immersion colonoscopy. The most common cause of unsuccessful CI was redundant colon (n=39, 34%) followed by strictures/angulations (n=16, 14%). 105 (91%) patients underwent repeat WE colonoscopy only, while 7 (6%) patients had combination WE and AI colonoscopy and 4 (3%) patients had concurrent gastroscopy. CI was successful in 114 (98%) patients and unsuccessful in 2 (2%) patients. 87 (75%) study patients received conscious sedation, 16 (14%) opted for no sedation, and 7 (6%) attempted no sedation then switched to conscious sedation. 5 patients (4%) required general anesthesia. CI was achieved in all 16 unsedated patients. 236 polyps were identified in 79 (68%) patients, 2 (1%) of which were malignant.

Conclusions

There is no standardized approach to incomplete colonoscopy. In this cohort of patients with previous failed attempt at colonoscopy, WE as a primary technique was associated with a high success rate with minimal need for general anesthesia and a high rate of polyp detection. A significant rate of colon cancer was identified, similar to that seen in general screening populations.

Funding Agencies

None

Opportunities in cancer imaging: a review of oesophageal, gastric and colorectal malignancies

The incidence of gastrointestinal (GI) malignancy is increasing worldwide. In particular, there is a concerning rise in incidence of GI cancer in younger adults. Direct endoscopic visualisation of luminal tumour sites requires invasive procedures, which are associated with certain risks, but remain necessary because of limitations in current imaging techniques and the continuing need to obtain tissue for diagnosis and genetic analysis; however, management of GI cancer is increasingly reliant on non-invasive, radiological imaging to diagnose, stage, and treat these malignancies. Oesophageal, gastric, and colorectal malignancies require specialist investigation and treatment due to the complex nature of the anatomy, biology, and subsequent treatment strategies. As cancer imaging techniques develop, many opportunities to improve tumour detection, diagnostic accuracy and treatment monitoring present themselves. This review article aims to report current imaging practice, advances in various radiological modalities in relation to GI luminal tumour sites and describes opportunities for GI radiologists to improve patient outcomes.

Liver perfusion MRI in a rodent model of cirrhosis: Agreement with bulk-flow phase-contrast MRI and noninvasive evaluation of inflammation in chronic liver disease using flow-sensitive alternating inversion recovery arterial spin labelling and tissue T1

Noninvasive measurements of liver perfusion and fibrosis in cirrhotic small animals can help develop treatments for haemodynamic complications of liver disease. Here, we measure liver perfusion in cirrhotic rodents using flow-sensitive alternating inversion recovery arterial spin labelling (FAIR ASL), evaluating agreement with previously validated caval subtraction phase-contrast magnetic resonance imaging (PCMRI) total liver blood flow (TLBF). Baseline differences in cirrhotic rodents and the haemodynamic effects of acute inflammation were investigated using FAIR ASL and tissue T1. Sprague-Dawley rats (nine bile duct ligated [BDL] and ten sham surgery controls) underwent baseline hepatic FAIR ASL with T1 measurement and caval subtraction PCMRI (with two-dimensional infra-/supra-hepatic inferior vena caval studies), induction of inflammation with intravenous lipopolysaccharide (LPS) and repeat liver FAIR ASL with T1 measurement after ~90 minutes. The mean difference between FAIR ASL hepatic perfusion and caval subtraction PCMRI TLBF was -51 ± 30 ml/min/100 g (Bland-Altman 95% limits-of-agreement ±258 ml/min/100 g). The FAIR ASL coefficient of variation was smaller than for caval subtraction PCMRI (29.3% vs 50.1%; P = .03). At baseline, FAIR ASL liver perfusion was lower in BDL rats (199 ± 32 ml/min/100 g vs sham 316 ± 24 ml/min/100 g; P = .01) but liver T1 was higher (BDL 1533 ± 50 vs sham 1256 ± 18 ms; P = .0004). Post-LPS FAIR ASL liver perfusion response differences were observed between sham/BDL rats (P = .02), approaching significance in sham (+78 ± 33 ml/min/100 g; P = .06) but not BDL rats (-49 ± 40 ml/min/100 g; P = .47). Post-LPS differences in liver tissue T1 were nonsignificant (P = .35). FAIR ASL hepatic perfusion and caval subtraction PCMRI TLBF agreement was modest, with significant baseline FAIR ASL liver perfusion and tissue T1 differences in rodents with advanced cirrhosis compared with controls. Following inflammatory stress, differences in hepatic perfusion response were detected between cirrhotic/control animals, but liver T1 was unaffected. Findings underline the potential of FAIR ASL in the assessment of vasoactive treatments for patients with chronic liver disease and inflammation.

Assessment of body composition and association with clinical outcomes in patients with lung and colorectal cancer

Objectives:

To assess body composition in patients with non-small cell lung cancer (NSCLC) and colorectal cancer using whole-body MRI and relate this to clinical outcomes.

Methods:

53 patients with NSCLC (28 males, 25 females; mean age 66.9) and 74 patients with colorectal cancer (42 males, 32 females; mean age 62.9) underwent staging whole-body MRI scans, which were post-processed to derive fat mass (FM), fat free mass (FFM) and skeletal muscle (SM) indices and SM fat fraction (FF). These were compared between the two cancer cohorts using two-sided t-tests and the chi-squared test. Measurements of body composition were correlated with outcomes including length of hospital stay, metastatic status and mortality.

Results:

Patients with NSCLC had significantly lower FFM (p = 0.0071) and SM (p = 0.0084) indices. Mean SM FF was greater in patients with NSCLC (p = 0.0124) and was associated with longer hospital stay (p = 0.035). There was no significant relationship between FM, FFM and SM indices and length of hospital stay, metastatic status or mortality.

Conclusions:

Patients with NSCLC had lower FFM and SM indices than patients with colorectal cancer and greater SMFF, indicating lower SM mass with fatty infiltration. These findings reflect differences in the phenotype of the two groups and suggest patients with lung cancer are more likely to require additional nutritional support.

Advances in knowledge:

Body composition differs between NSCLC and colorectal cancer. Patients with NSCLC have both a reduced SM mass and greater SM FF suggesting that they are more nutritionally deplete than patients with colorectal cancer.

A273 ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY IN A TERTIARY CANADIAN HOSPITAL: OPTIMIZING TISSUE SAMPLING TECHNIQUES

Background

Pancreatic and biliary cancer can be difficult to definitively diagnose, and tissue diagnosis defines clinical management in both early and late disease. The majority of patients with pancreaticobiliary malignancy present with late disease and only 30% have resectable tumours, contributing to poor prognosis and outcome. Endoscopic retrograde cholangiopancreatography (ERCP) is a mainstay for diagnosing and treating conditions of the bile and pancreatic duct.

Aims

This study aimed to provide data on the diagnostic performance of ERCP utilizing conventional methods for tissue acquisition particularly in the setting of an indeterminate stricture. In particular, this was a quality assurance review to determine our centre’s baseline performance as a reference so new methods of tissue acquisition such as SpyglassTM can be benchmarked against.

Methods

In a tertiary care hospital, 3723 ERCP procedures were performed between 2013 and 2017. Demographic and clinical information was retrospectively collected. Demographic and clinical information was collected. Three ERCP techniques of tissue sampling were analyzed: brushing alone (BiA), biopsy alone (BrA), and brushing and biopsy dual-modality approach (BrBi). The diagnostic performances (sensitivity, specificity, and accuracy) were calculated with data from post-sampling clinical reports, surgical pathological reports, and diagnostic imaging reports.

Results

222 patients (285 ERCP procedure) met the study criteria and received fluoroscopy-guided ERCP sampling with cytology brushing and/or tissue biopsies. 36 (13%) patients had BiA, 85 (29%) patients had BrA, and 164 (58%) patients had BrBi. The sensitivities, specificities, and accuracies of the three sampling techniques respectively were: 56%, 93%, and 85% for BiA; 73%, 96%, and 83% for BrA; and 79%, 94%, and 86% for BrBi.

Conclusions

Our retrospective analysis of fluoroscopic-guided tissue acquisition shows accuracy as high as current published data on direct visualization cholangiosopy guided techniques. A prospective study looking not only at clinical yield but a cost analysis should be put in place prior to a commitment to purchase new equipment such as the SpyglassTM.

Funding Agencies

None

The evolution of magnetic resonance enterography in the assessment of motility disorders in children

Gastrointestinal symptoms including constipation, diarrhoea, pain and bloating represent some of the most common clinical problems for patients. These symptoms can often be managed with cheap, widely available medication or will spontaneously resolve. However, for many patients, chronic GI symptoms persist and frequently come to dominate their lives. At one end of the spectrum there is Inflammatory Bowel Disease (IBD) with a clearly defined but expensive treatment pathway. Contrasting with this is Irritable Bowel Syndrome (IBS), likely a collection of pathologies, has a poorly standardised pathway with unsatisfactory clinical outcomes. Managing GI symptoms in adult populations is a challenge. The clinical burden of gastrointestinal disease is also prevalent in paediatric populations and perhaps even harder to treat. In this review we explore some of the recent advances in magnetic resonance imaging (MRI) to study the gastrointestinal tract. Complex in both its anatomical structure and its physiology we are likely missing key physiological markers of disease through relying on symptomatic descriptors of gut function. Using MRI we might be able to characterise previously opaque processes, such as non-propulsive contractility, that could lead to changes in how we understand even common symptoms like constipation. This review explores recent advances in the field in adult populations and examines how this safe, objective and increasingly available modality might be applied to paediatric populations.

Relationship between MRI quantified small bowel motility and abdominal symptoms in Crohn's disease patients-a validation study

OBJECTIVE

Previous single-centre MRI data suggests an inverse correlation between normal small bowel motility variance and abdominal symptoms in Crohn's disease (CD) patients. The current work prospectively assesses this observation in a larger, two-centre study.

METHODS

MR enterography datasets were analysed from 82 patients (38 male, aged 16-68), who completed a contemporaneous Harvey-Bradshaw index (HBI) questionnaire. Dynamic "cine motility" breath-hold balanced steady-state free precession sequences were acquired through the whole small bowel (SB) volume. Regions of interest (ROIs) were manually applied to encompass all morphologically normal SB (i.e. excluding Crohn's affected bowel) and a validated registration technique used to produce motility maps. Mean and variance motility metrics were correlated with HBI and symptom components (well-being, pain and diarrhoea) using Spearman's correlation statistics.

RESULTS

Overall, motility variance was non-significantly negatively correlated with the total HBI score, (r = -0.17, p = 0.12), but for subjects with a HBI score over 10, the negative correlation was significant (r = -0.633, p = 0.027). Motility variance was negatively correlated with diarrhoea (r = -0.29, p < 0.01). No significant correlation was found between mean motility and HBI (r = -0.02, p = 0.84).

CONCLUSION

An inverse association between morphologically normal small bowel motility variance and patient symptoms has been prospectively confirmed in patients with HBI scores above 10. This association is particularly apparent for the symptom of diarrhoea. Advances in knowledge: This study builds on preliminary work by confirming in a large, well-controlled prospective multicentre study a relationship between normal bowel motility variance and patient reported symptoms which may have implications for drug development and clinical management.

MRI assessment of the postprandial gastrointestinal motility and peptide response in healthy humans

BACKGROUND

Feeding triggers inter-related gastrointestinal (GI) motor, peptide and appetite responses. These are rarely studied together due to methodological limitations. Recent MRI advances allow pan-intestinal, non-invasive assessment of motility in the undisturbed gut. This study aimed to develop a methodology to assess pan-intestinal motility and transit in a single session using MRI and compare imaging findings to GI peptide responses to a test meal and symptoms in a healthy volunteer cohort.

METHODS

Fifteen healthy volunteers (29.3±2.7 years and BMI 20.1±1.2 kg m^-2 ) underwent baseline and postprandial MRI scans, symptom questionnaires, and blood sampling (for subsequent GI peptide analysis, Glucagon-like peptide-1 [GLP-1], Polypeptide YY [PYY], Cholecystokinin [CCK]) at intervals for 270 minutes following a 400 g soup meal (204 kcal, Heinz, UK). Gastric volume, gall bladder volume, small bowel water content, small bowel motility, and whole gut transit were measured from the MRI scans.

KEY RESULTS

(mean±SEM) Small bowel motility index increased from fasting 39±3 arbitrary units (a.u.) to a maximum of 87±7 a.u. immediately after feeding. PYY increased from fasting 98±10 pg mL^-1 to 149±14 pg mL^-1 at 30 minutes and GLP-1 from fasting 15±3 μg mL^-1 to 22±4 μg mL^-1 . CCK increased from fasting 0.40±0.06 pmol mL^-1 to 0.94±0.1 pmol mL^-1 . Gastric volumes declined with a T_1/2 of 46±5 minute and the gallbladder contracted from a fasting volume of 19±2 mL^-1 to 12±2 mL^-1 . Small bowel water content increased from 39±2 mL^-1 to 51±2 mL^-1 postprandial. Fullness VAS score increased from 9±5 mm to 41±6 mm at 30 minutes postprandial.

CONCLUSIONS AND INFERENCES

The test meal challenge was effective in inducing a change in MRI motility end-points which will improve understanding of the pathophysiological postprandial GI response.

The development of a magnetic resonance imaging index for fistulising Crohn's disease

BACKGROUND

Magnetic resonance imaging (MRI) is the gold standard for assessment of perianal fistulising Crohn's disease (CD). The Van Assche index is the most commonly used MRI fistula index.

AIMS

To assess the reliability of the Van Assche index, and to modify the instrument to improve reliability and create a novel index for fistulising CD.

METHODS

A consensus process developed scoring conventions for existing Van Assche index component items and new items. Four experienced radiologists evaluated 50 MRI images in random order on three occasions. Reliability was assessed by estimates of intraclass correlation coefficients (ICCs). Common sources of disagreement were identified and recommendations made to minimise disagreement. A mixed effects model used a 100 mm visual anologue scale (VAS) for global severity as outcome and component items as predictors to create a modified Van Assche index.

RESULTS

Intraclass correlation coefficients (95% confidence intervals) for intra-rater reliability of the original and modified Van Assche indices and the VAS were 0.86 (0.81-0.90), 0.90 (0.86-0.93) and 0.86 (0.82-0.89). Corresponding ICCs for inter-rater reliability were 0.66 (0.52-0.76), 0.67 (0.55-0.75) and 0.58 (0.47-0.66). Sources of disagreement included number, location, and extension of fistula tracts, and rectal wall involvement. A modified Van Assche index (range 0-24) was created that included seven component items.

CONCLUSIONS

Although "almost perfect" intra-rater reliability was observed for the assessment of MRI images for fistulising CD using the Van Assche index, inter-rater reliability was considerably lower. Our modification of this index should result in a more optimal instrument.

A magnetic resonance imaging study of gastric motor function in patients with dyspepsia associated with Ehlers-Danlos Syndrome-Hypermobility Type: A feasibility study

BACKGROUND

The clinical use of Magnetic Resonance Imaging (MRI) for investigating gastric motor function in dyspepsia is limited, largely due to protocol complexity, cost and limited availability. In this study, we explore the feasibility of a sub 60-minute protocol using a water challenge to assess gastric emptying, motility and accommodation in a cohort of Ehlers-Danlos Syndrome-Hypermobility type (EDS-HT) patients presenting with dyspepsia.

METHODS

Nine EDS-HT patients (mean age 33, range: 26-50 all female) with a history of dyspepsia were recruited together with nine-matched controls. Subjects fasted for 6 hours prior to MRI. A baseline anatomical and motility scan was performed after which the subjects ingested 300 mL water. The anatomical and motility scans were then repeated every 10 minutes to a total of 60 minutes. Gastric emptying time, motility, and accommodation were calculated based on the observations of two observers for each EDS-HT subject and compared to their matched control using paired statistics.

KEY RESULTS

Median motility increase following the water challenge was lower in EDS-HT subjects (11%, range: 0%-22%) compared to controls (22%, range: 13%-56%), P=.03. Median gastric emptying time was non-significantly decreased in EDS-HT subjects (12.5 minutes, range: 6-27) compared to controls (20 minutes, range: 7-30), P=.15. Accommodation was non-significantly reduced in EDS-HT subjects (56% increase, range: 32%-78%) compared to healthy controls (67% increase, range: 52%-78%), P=.19.

CONCLUSIONS & INFERENCES

This study demonstrates the feasibility of a water challenge MRI protocol to evaluate gastric physiology in the clinical setting. Motility differences between EDS-HT and controls are worthy of further investigation.

Safety and acceptability of an organic light-emitting diode sleep mask as a potential therapy for retinal disease

PurposeThe purpose of the study was to study the effect of an organic light-emitting diode sleep mask on daytime alertness, wellbeing, and retinal structure/function in healthy volunteers and in diabetic macular oedema (DMO).Patients and methodsHealthy volunteers in two groups, 18-30 yrs (A), 50-70 yrs (B) and people with DMO (C) wore masks (504 nm wavelength; 80 cd/m² luminance; ≤8 h) nightly for 3 months followed by a 1-month recovery period. Changes from baseline were measured for (means): psychomotor vigilance task (PVT) (number of lapses (NL), response time (RT)), sleep, depression, psychological wellbeing (PW), visual acuity, contrast sensitivity, colour, electrophysiology, microperimetry, and retinal thickness on OCT.ResultsOf 60 participants, 16 (27%) withdrew, 8 (13%) before month 1, due to sleep disturbances and mask intolerance. About 36/55 (65%) who continued beyond month 1 reported ≥1 adverse event. At month 3 mean PVT worsened in Group A (RT (7.65%, P<0.001), NL (43.3%, P=0.005)) and mean PW worsened in all groups (A 28.0%, P=0.01, B 21.2%, P=0.03, C 12.8%, P<0.05). No other clinically significant safety signal was detected. Cysts reduced/resolved in the OCT subfield of maximal pathology in 67% Group C eyes. Thinning was greater at 3 and 4 months for greater baseline thickness (central subfield P<0.001, maximal P<0.05).ConclusionSleep masks showed no major safety signal apart from a small impairment of daytime alertness and a moderate effect on wellbeing. Masks were acceptable apart from in some healthy participants. Preliminary data suggest a beneficial effect on retinal thickness in DMO. This novel therapeutic approach is ready for large clinical trials.