Case series of keratitis in poultry abattoir workers induced by exposure to the ultraviolet disinfection lamp

Photokeratitis in Outdoor Event Participants Exposed to UV Radiation Display

Importance

While UV radiation displays may be used for recreational purposes at outdoor events, unprotected eyes have been reported to have symptoms consistent with photokeratitis. Such symptoms warrant documentation and evaluation in ophthalmic peer reviewed literature.

Objective

To describe a case series of photokeratitis associated with a single ultraviolet radiation display at an outdoor event.

Design, Setting, and Participants

This case series involved a retrospective record review of 8 patients who presented in public and private health sectors in November 2023 after developing photokeratitis following UV radiation exposure at an outdoor event in Hong Kong on the night of November 4, 2023.

Main Outcomes and Measures

Clinical symptoms, signs, and clinical course of patients who were diagnosed acute photokeratitis following exposure to UV radiation.

Results

The mean time of UV display exposure for the 8 patients (mean [SD] age, 33.12 [5.19] years; 4 [50%] female) was 3.00 (1.41) hours, and symptoms presented at a mean (SD) 8.88 (8.24) hours after the exposure. None of the patients were wearing spectacles during the exposed period. All patients were affected bilaterally. All patients experienced eye pain, 6 experienced red eye, and 5 experienced tearing and photophobia. Mean (SD) presenting visual acuity was logMAR 0.10 (0.14) (approximate Snellen equivalent, 20/25) for right eyes and 0.06 (0.89) (approximate Snellen equivalent, 20/25) for left eyes. On examination, there were findings of cornea and conjunctival involvement with punctate epithelial erosions and ciliary vasodilation, but none of the patients presented with anterior chamber reaction. Corticosteroids, lubricants, and antibiotics, all provided topically, were prescribed. Five patients were not scheduled for a review, and 3 had follow-up visits, with the length of follow-up ranging from 7 to 10 days. All patients had undergone a complete recovery.

Conclusions and Relevance

These findings provide evidence of an association between UV radiation used for recreational purposes and photokeratitis, which may help guide evaluation and management of future cases.

UV Protection in the Cornea: Failure and Rescue

Simple Summary

The sun is a deadly laser, and its damaging rays harm exposed tissues such as our skin and eyes. The skin’s protection and repair mechanisms are well understood and utilized in therapeutic approaches while the eye lacks such complete understanding of its defenses and therefore often lacks therapeutic support in most cases. The aim here was to document the similarities and differences between the two tissues as well as understand where current research stands on ocular, particularly corneal, ultraviolet protection. The objective is to identify what mechanisms may be best suited for future investigation and valuable therapeutic approaches.

Abstract

Ultraviolet (UV) irradiation induces DNA lesions in all directly exposed tissues. In the human body, two tissues are chronically exposed to UV: the skin and the cornea. The most frequent UV-induced DNA lesions are cyclobutane pyrimidine dimers (CPDs) that can lead to apoptosis or induce tumorigenesis. Lacking the protective pigmentation of the skin, the transparent cornea is particularly dependent on nucleotide excision repair (NER) to remove UV-induced DNA lesions. The DNA damage response also triggers intracellular autophagy mechanisms to remove damaged material in the cornea; these mechanisms are poorly understood despite their noted involvement in UV-related diseases. Therapeutic solutions involving xenogenic DNA-repair enzymes such as T4 endonuclease V or photolyases exist and are widely distributed for dermatological use. The corneal field lacks a similar set of tools to address DNA-lesions in photovulnerable patients, such as those with genetic disorders or recently transplanted tissue.

An outbreak of bilateral photokeratitis and eyelid erythema following exposure to an artificial source of ultraviolet radiation, Tamil Nadu, India, 2018

Metal halide lights (MHLs) emit ultraviolet radiation (UVR) and should be used with enclosed fixtures. We investigated a cluster of blurred vision in a locality in South India reported among light music event attendees to identify risk factors.

METHODS

We searched for attendees with any eye-related symptoms by door-to-door. We described cases by time, place, and person and inspected the environment to generate a hypothesis. We followed-up the cohort of the attendees to examine the hypothesis of exposure to MHL as the cause of the outbreak. We computed relative risk (RR) and 95% confidence interval (CI) by comparing attack rates among attendees by seating location and duration of exposure.

RESULTS

Of the total 500 attendees, we could interview 319 (64%) and 89% (284/319) attendees developed bilateral photokeratitis (median age = 24 years [range: 2-80 years]). Attack rate was higher among female (92% [172/189]) than male (85% [110/130]). Attack rate among those seated within 12 meters from dais was higher (95% [241/253]) than the rest (65% [43/66]; RR = 1.5; 95% CI = 1.2, 1.7) and attack rate was higher among those continuously exposed to MHL (97% [268/277]) than others (38% [16/42]; RR = 2.5; 95% CI = 1.7, 3.7). The duration of exposure was associated with increased risk of bilateral photokeratitis (χ2 test for linear trend = 74; P < 0.00001). During the environmental inspection, we identified the use of MHL with a broken outer envelope.

CONCLUSIONS

Photokeratitis was associated with exposure to UVR from MHL with a broken outer envelope. We recommended the usage of MHL along with enclosed fixtures.

Photobiomodulation of the Visual System and Human Health

Humans express an expansive and detailed response to wavelength differences within the electromagnetic (EM) spectrum. This is most clearly manifest, and most studied, with respect to a relatively small range of electromagnetic radiation that includes the visible wavelengths with abutting ultraviolet and infrared, and mostly with respect to the visual system. Many aspects of our biology, however, respond to wavelength differences over a wide range of the EM spectrum. Further, humans are now exposed to a variety of modern lighting situations that has, effectively, increased our exposure to wavelengths that were once likely minimal (e.g., “blue” light from devices at night). This paper reviews some of those biological effects with a focus on visual function and to a lesser extent, other body systems.

Simulated Mass Casualty Incident Triage Exercise for Training Medical Personnel

Audience

The target audience is any medical professional who requires training in mass casualty incident (MCI) triage. This could apply to pre-hospital specialists, nurses, medical students, residents, and physicians.

Introduction

Emergency medicine specialists must be able to triage patients quickly, especially in an MCI scenario. The simple triage and rapid treatment (START) system allows providers to categorize patients according to the urgency with which patients must access limited resources. Providers should be comfortable utilizing the START triage system before an MCI or disaster so that they can be prepared to implement it if necessary. This exercise uses simulation and gamification as instructional strategies to encourage knowledge of and comfort with the START triage system for emergency providers.

Educational Objectives

By the end of this exercise, learners should be able to (1) recite the basic START patient categories (2) discuss the physical exam signs associated with each START category, (3) assign roles to medical providers in a mass casualty scenario, (4) accurately categorize patients into triage categories: green, yellow, red, and black, and (5) manage limited resources when demand exceeds availability.

Educational Methods

Gamification is the use of elements of game design in non-game contexts.1 Gamification was implemented in this scenario by assigning participants to roles and teams, while creating an engaging, fun, and competitive environment. The exercise also uses low fidelity simulation (without simulation equipment) to encourage learners to practice using the START triage system in a low stakes environment.2 It is possible for the learners to be divided into two groups that each have the same patients, resources, and objectives. The team that finishes triaging all patients first would be declared the winner. However, in our implementation, we completed the exercise as a single group of learners and patients.

Research Methods

Learners were given a survey at the end of implementation and also given the opportunity to discuss feedback with the instructors in a group discussion after completing the exercise. There was no formal assessment completed after the exercise.

Results

Informal feedback was collected at the end of the exercise. Residents and medical students all enjoyed the experience. The feedback was overwhelmingly positive. All participants providing feedback stated they would enjoy participating in the exercise again and suggested that it is implemented annually for review of triage topics. We also received informal feedback for suggested changes which we will discuss in this article. An optional, anonymous survey was given to participants at the end of the exercise. There were six responses. Of those surveyed, 100% of participants stated the effectiveness and value of the exercise was outstanding (a rating of five on a scale of one to five). Regarding the quality of the exercise, and whether the participants felt engaged, 100% of responses gave a rating of five. When asked to consider the relevance of the session, 100% of participants selected a score of five ("I loved this session"). Regarding whether the content was applicable to practice of emergency medicine, 80% of respondents stated the session was highly relevant and 20% of responses selected a score of mostly relevant. One question asked for points of improvement for the session to which there were no responses.

Discussion

Learners were assigned roles in the exercise by the incident commander, fulfilling objective three. The START categories were discussed at the beginning of the exercise by the lead proctor (using PowerPoint) and then utilized throughout the exercise, thus accomplishing objectives one and two. The residents/students filling the triage roles were primarily responsible for fulfilling objective four; however, all participants assisted in categorization of patients throughout the exercise. Finally, objective five was addressed through the various social situations and complications that can be implemented during the exercise. We chose not to implement the additional "radiation contamination" scenario (details available in the article text) due to time constraints; however, this is an additional option to address objective five. The implementation was effective based on informal feedback from participants and proctors as well as evidenced by the responses to the anonymous survey. Learners found the aspects of resource management, review of START triage, repetition of the START triage system, and medical management of various types of trauma informative and meaningful. We received valuable feedback from both learners and proctors, which we will discuss in this article.

Topics

Mass casualty incident, disaster, START, gamification, simulation, emergency medicine, triage, triage category, contamination, teamwork, trauma, projectile trauma, penetrating injury, blunt trauma, intracranial hemorrhage, fracture, trauma in pregnancy, active shooter, radiation, radio communication.

The Bystander Effect of Ultraviolet Radiation and Mediators

A bystander effect is biological changes in non-irradiated cells by transmitted signals from irradiated bystander cells, which causes the radiation toxic effects on the adjacent non-irradiated tissues. This phenomenon occurs by agents such as ionizing radiation, ultraviolet radiation (UVR) and chemotherapy. The bystander effect includes biological processes such as damage to DNA, cell death, chromosomal abnormalities, delay and premature mutations and micronuclei production. The most involved genes in creating this phenomenon are cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), the nuclear factor of kappa B (NFkB) and Mitogen-Activated Protein Kinases (MAPKs). Radiation generated reactive oxygen species (ROS) can damage DNA, membranes and protein buildings. Studies have shown that Vitamin C, Hesperidin, and melatonin can reduce the number of ROS and have a protective role. Silver nanoparticles (Ag NPs) are the most abundant nanoparticles produced and when they enter cells, they can create DNA damage. Studies have shown that combined treatment with UVR and silver nanoparticles could form γ-H2AX and 8-hydroxy-2'-deoxyguanosine (8-OHdG) synergistically. This article reviews the direct and the bystander effects of UVR on the nuclear DNA, the effect of radioprotectors and Ag NPs on these effects.

Impact of Silver Nanoparticles on the Ultraviolet Radiation Direct and Bystander Effects on TK6 Cell Line

PURPOSE/AIM

Ultraviolet C (UVC) radiation is harmful to cells and living organisms that cause direct and indirect DNA damage. UVC can also increase the inflammatory genes expression such as COX-2 that results in elevated oxidative stress that plays a role in radiation-induced bystander effect (BSE). Silver nanoparticles (AgNPs) have used widely in commercial and medical products and the toxicological risks of AgNPs must be determined. The aim of this study was to investigate the direct and BSEs of UVC radiation and AgNPs on TK6 cell line.

MATERIALS AND METHODS

TK6 cells were exposed to AgNPs (10 μg/ml, 1 h). Then, they were exposed to UVC and to determine the BSEs of radiation, the irradiated cells media were transferred to nonirradiated cells. Expression level of H2AX and COX-2 mRNAs were examined by quantitative real-time PCR and 8-OHdG formation was examined by ELISA. The cell viability examined by MTT assay.

RESULTS

P < 0.05 was considered as the level of significance. The results showed that the mean expression level of H2AX mRNA in the AgNPs + UVC group increased significantly in comparison with UVC group. 8-OHdG increased significantly in the BSE of UV group in comparison with sham control of BSE. COX-2 mRNA increased significantly in the BSE of AgNPs + UVC with sham control in BSE.

CONCLUSIONS

Our findings showed the induced DNA damage in TK6 cell by AgNPs and UVC radiation and also were seen BSE.

Photokeratitis among restaurant workers: A case series

This case report highlights the challenges associated with the diagnosis and workplace evaluation of occupationally acquired ultraviolet (UV) radiation-induced photokeratitis and associated skin burns in a group of restaurant workers. UV-C spectrum bulbs were inadvertently shipped and installed in insect light traps. Ocular and dermal symptoms were reported in 18 of 85 restaurant employees to varying degrees of severity over a 2-day period. One patient was formally diagnosed with a chemical burn/irritation of the cornea. More severe symptoms were reported by individuals working in close proximity to the lights. This clinical picture can resemble mass chemical or irritant exposure when multiple individuals are affected, and a multidisciplinary approach was required for rapid identification of the source to limit morbidity. Prevention strategies for similar events should be considered which can include limiting hardware compatibility and improving warning labels.