Characterizing visual field loss from past mercury exposure in an Indigenous riverine community (Grassy Narrows First Nation, Canada): a cluster-based approach.

BACKGROUND: Between 1962 and 1975, a chlor-alkali plant in Canada discharged approximately 9 metric tons of mercury (Hg) into the Wabigoon River. Over the following decades, biomarkers of Hg exposure of persons from Grassy Narrows First Nation (Asubpeeschoseewagong Anishinabek), located downriver from the discharge, reflected Hg concentrations in fish. Hg exposure is known to target the calcarine fissure, resulting in visual field (VF) loss. Most studies and clinical reports focus solely on peripheral VF loss; little is known about the impact of Hg on the central and paracentral portions. The present study sought to characterize the patterns of VF loss with respect to past and current Hg. METHODS: A 28-year hair-Hg (HHg) database, created from a 1970-97 government biomonitoring program, served to select study participants with ≥ 4 year-based HHg measurements (n = 81). Blood-Hg was assessed for current exposure. Light sensitivity thresholds across the VF were analyzed monocularly, using a Humphrey Field Analyzer (HFA). Following post-hoc exclusions, based on HFA interpretation indices, 65 participants were retained. Both eyes were combined for analyses (n = 130 eyes). Unsupervised hierarchical clustering of HFA plot data was used to identify patterns of VF loss. A series of mixed effects models (MEM) were performed to test the associations for current Hg exposure with respect to HFA interpretation indices and clusters, as well as for longitudinal past Hg exposure. RESULTS: The clustering approach decomposed the light sensitivity deficits into 5 concentric clusters, with greatest loss in the peripheral clusters. No relation was observed between any of the cluster scores and current blood-Hg. VF deficits increased with past Hg exposure. Longitudinal MEM showed that HHg was significantly (p < 0.05) associated with all peripheral, paracentral, and central cluster scores, as well as with HFA interpretation indices. CONCLUSIONS: Past Hg exposure in Grassy Narrows First Nation was associated with present day VF loss. The cluster-based location-specific approach identified patterns of VF loss associated with long-term Hg exposure, in both the peripheral and the central areas. The functional implications of this type of visual loss should be investigated.

Bilateral Visual Impairment following Combination Chemotherapy with Carboplatin in Patients with Small Cell Lung Cancer: A Case Report.

Background: Platinum-based combination chemotherapy, including cisplatin and carboplatin, are important cytotoxic anti-cancer agents that are widely used to treat various solid tumors. Carboplatin has a similar effect on survival in small cell lung cancer, but generally has a milder toxicity profile when compared with cisplatin. Both may cause moderate or severe neurotoxicity, but ocular neurotoxicity from carboplatin is rarely reported. Case presentation: A 79-year-old man underwent intravenous polychemotherapy (atezolizumab, etoposide, and carboplatin) for small cell lung cancer. One week after the second cycle of chemotherapy, he reported bilateral visual loss as hand motion in both eyes. Dilated fundus examination showed retinal arterial narrowing without hemorrhage, and diffuse choroidal and retinal thinning was observed in an optical coherence tomography scan. Fluorescein angiography revealed significantly delayed circulation without evidence of obstructive lesions. 30-Flicker electroretinogram testing showed a complete absence of cone response in both eyes. The patient's visual acuity aggravated to no light perception in both eyes, even after the cessation of chemotherapy. Conclusions: Carboplatin combination chemotherapy administered at therapeutic doses can result in irreversible visual loss, a side effect that is not widely acknowledged. When using carboplatin, physicians should be aware of its potential ocular toxicity.

Praziquantel-related visual disorders among recipients in mass drug administration campaigns in schistosomiasis endemic settings: Systematic review and meta-analysis protocol.

BACKGROUND: Hundreds of millions of doses of Praziquantel (PZQ) have been administered to persons with and without schistosomiasis living in schistosomiasis endemic settings, through the mass drug administration (MDA) strategy which started in the early 2000s. A recent publication suggested high risk of PZQ-related visual disorders, raising public health concerns. We aim to systematically synthesize evidence on the magnitude of PZQ-related visual disorders. METHODS: We will search PubMed, Google Scholar, CINAHL, SCOPUS, CENTRAL and LILACS from 1977 (when the first human clinical trials on PZQ started) to 31st May 2024, with no language restrictions. The key search terms will include "Praziquantel", "PZQ", "visual disorder", "adverse events", "side effects", "blurry vision" and "visual impairment" together with alternative terms and synonyms. All the countries endemic for schistosomiasis will be included as search terms. We will also search HINARI, Africa Journals Online, Thesis Databases and Preprint Repositories. Where necessary, we will contact expert researchers working in the field of schistosomiasis, UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), pharmaceutical industries, country-specific Food and Drug Authorities (FDAs) and the European Medicines Agency databases. We will search Conference Proceedings and reference lists of relevant studies for additional studies. At least two authors will independently select studies, extract data and assess risk of bias in the included studies. Any disagreements or discrepancies will be resolved through discussion between the reviewers. Heterogeneity will be explored graphically, and statistically using the I2-statistic. We will conduct random-effects meta-analysis when heterogeneity is appreciable, and express dichotomous outcomes (visual adverse events including excessive lacrimation, blurry vision and visual impairments) as risk ratio (RR) or Odds Ratio (OR) with their 95% confidence interval (CI). We will perform subgroup analysis to assess the impact of heterogeneity, and sensitivity analyses to test the robustness of the effect estimates. The overall level of evidence will be assessed using GRADE. EXPECTED OUTCOMES: The present review expects to identify and categorize visual disorders occurring after administration of PZQ, alone or in combination with other drugs. By synthesizing the data from multiple studies, the review aims to present a quantitative assessment of the risk or odds of experiencing a visual disorder in different populations after ingesting PZQ. The review will also generate insights into whether PZQ in combination with other drugs are associated with increased odds of visual disorders and whether the occurrence of visual disorders correlates with dosage or treatment duration. Policymakers, public health experts and stakeholders could rely on the review findings to deliver context-sensitive preventive chemotherapy programs by adjusting drug combinations or dosing schedules to reduce risk of visual adverse effects in populations treated with PZQ. The review aims to identify gaps in the current evidence regarding visual disorders following PZQ administration in schistosomiasis endemic settings which can serve as the basis for future research on important but unanswered questions. DISSEMINATION AND PROTOCOL REGISTRATION: The findings of this study will be disseminated through stakeholder forums, conferences, and peer-review publications. The review protocol has been registered in the International Prospective Register for Systematic Reviews (PROSPERO)- CRD42023417963.

Reconsideration of Surgical Indication for Prolactin-producing Pituitary Tumor Focusing on Visual Impairment.

Prolactin-producing pituitary tumor (PRLoma) is the most prevalent functional pituitary tumor. If the tumor becomes large, vision can be impaired. In contrast to other pituitary tumors, cabergoline (CAB) is extremely effective for PRLoma and has become the first-line treatment. In this study, we examined our experience with the pharmacological and surgical management of PRLomas with visual impairment (VI) to determine whether VI could be a surgical indication. Further, we discussed the function of surgery in situations where the gold standard of PRLoma treatment was CAB administration. Of the 159 patients with PRLomas (age, 13-77 [mean = 36.3] years; men, 29; women, 130) at Tokyo Women's Medical University Hospital from 2009 to 2021, 18 (age, 15-67 [mean = 35.8] years; men, 12; woman, 6) had VI (subjectively, 12; objectively, 6). They started CAB treatment immediately (maximum dose: 0.5 to 6 mg/week; average: 2.17 mg/week). VI improved in 16 patients (88.9%) but did not improve in 2 (11.1%) requiring surgeries. One of the two patients had a parenchymal tumor resistant to CAB, and the other had a cystic tumor due to intratumoral bleeding. Consequently, CAB is the first-line treatment for PRLomas with VI because of its significantly high rate of improvement. However, close and rigorous surveillance is necessary for cases resistant to CAB, and the correct decision is required regarding surgical interventions at proper timing and appropriate surgical approaches considering the purpose of surgery.

Toxic encephalopathy, vision loss, and memory disorder caused by acute acrylamide exposure.

Acrylamide (ACR) is an irritant that can cause damage to the eyes, skin, and nervous and reproductive systems. This study aims to illustrate a case of central nervous system and optic nerve damage from exposure to ACR. In this case, a 49-year-old male material handler was accidentally splashed with ACR solution on both of his upper limbs. Consequently, he was admitted to the hospital with toxic encephalopathy, characterized by cerebellar ataxia and slurred speech. Magnetic resonance imaging scan, a brain computed tomography scan blood sample analyses, optic coherence tomography, electroneuromyogram, and visual evoked potentials examination were performed. After 20 days of receiving symptomatic support treatment, the patient continued to experience disturbances in consciousness. Then, he developed vision loss, memory disorders, and symptoms of peripheral neuropathy such as skin peeling, extremity weakness, and absent tendon reflexes. This case report underscores the severe consequences of acute dermal exposure to high concentrations of ACR, resulting in toxic encephalopathy, visual impairment, and memory disorders, which will contribute to a broader understanding of ACR toxicity.

Ethambutol and its ophthalmic effects; is screening and collaboration the new way forward?

AIM: To screen patients on ethambutol and evaluate its role on visual functions and toxic optic neuropathy. SETTING AND DESIGN: Retrospective, observational single tertiary centre cohort of 80 patients. METHODS AND MATERIAL: A total of 69 from the initial 80 patients with visual complaints were categorised into two groups A and B; ongoing anti-tubercular therapy with ethambutol and having stopped ethambutol for greater than six months respectively. All patients underwent vision (V) testing on ETDRS chart and anterior and posterior segment evaluation. Additionally, patients in group A recorded color vision (CV) on Ishihara chart and visual evoked potential (VEP). STATISTICAL ANALYSIS USED: P value was calculated using Chi square test (SPSS ver. 20). RESULTS: Out of 69 patients in our study, 58 (84.05%) patients recorded reduced visual acuity. The mean visual acuity was 0.58 logMAR units. 33 out of our 58 (57%) patients with reduced visual acuity showed normal optic discs while 25 out of 58 (43%) showed altered optic discs. In group B, 14 out of 32 patients with vision of less than 20/20 also had optic disc pallor (p = 0.02). 12 out of 15 patients in group A recorded an altered color vision and also had a vision of less than 20/20 (p = 0.023). 15 patients who recorded altered VEP also had vision of less than 20/20 (p = 0.037). CONCLUSION: Visual acuity, color vision and vep are sensitive and sustainable tools which can be implemented in regular screening. Ethambutol toxicity is a real problem and a collaborative approach is necessary to establish screening protocols and prevent ethambutol induced toxic optic neuropathy.

Neurologic Complications in Critically Ill Patients with Toxic Alcohol Poisoning: A Multicenter Population-Based Cohort Study.

BACKGROUND: Toxic alcohol poisoning is regularly encountered in emergency departments and intensive care units (ICUs). Most patients present with an altered level of consciousness, but the subsequent course and spectrum of neurologic complications and outcomes is highly variable. METHODS: We performed a population-based, multicenter retrospective cohort study of critically ill patients with toxic alcohol poisoning admitted to ICUs in Alberta, Canada, between 2007 and 2019 to describe neurologic sequelae, including seizures, coma, neuroimaging abnormalities, persistent cognitive or visual impairment, and mortality. Multivariate analysis was performed to identify predictors of poor outcome. RESULTS: We identified 104 patients, including 55 (53%) with methanol ingestion, 36 (35%) with ethylene glycol ingestion, and 13 (13%) with isopropanol ingestion. In patients who underwent neuroimaging, abnormalities were detected in 9 of 24 (38%) with methanol toxicity, 5 of 20 (25%) with ethylene glycol toxicity, and 0 of 10 with isopropanol toxicity (p = 0.07). Basal ganglia were commonly involved with both methanol and ethylene glycol poisoning, but prominent subcortical involvement and restricted diffusion were observed only with methanol poisoning. The composite of death, persistent cognitive impairment, or visual loss occurred in 13 (24%) patients with methanol poisoning, compared with one (3%) with ethylene glycol poisoning and none with isopropanol poisoning (p = 0.006). Among patients with methanol toxicity, greater elevation of the anion gap and lower Glasgow Coma Scale score were independent predictors of poor outcome. No patient with an anion gap ≥ 28 at presentation had a favorable recovery. Progression to death by neurologic criteria occurred in 3 of 55 (5%) patients with methanol poisoning and in none with other toxic alcohols. CONCLUSIONS: Methanol overdose is the most common form of toxic alcohol poisoning to result in ICU admission. Poor neurologic outcomes may occur especially with methanol poisoning, with more than one in five patients dying or having persistent cognitive or visual impairment. A wide anion gap independently predicts poor outcome, emphasizing the importance of expeditious recognition and treatment.

Long-Term Visual and Neurodevelopmental Outcomes in Two Children with Congenital Nystagmus Secondary to Methadone Exposure In utero.

Methadone is used as a substitute for illicit opioids during pregnancy. However, the real effect of this molecule on visual and neurodevelopmental outcomes of the children exposed is not fully understood, since studies considered subjects born to polydrug-dependent mothers and followed for few months/years. We report the long-term outcomes of two infants with congenital nystagmus solely exposed to methadone in utero. Neurological and neurovisual evaluations were performed every year from the first year of life to 11 years of age. One child was diagnosed with developmental coordination disorder. Both cases presented with ophthalmologic (refractive errors), oculomotor (nystagmus and fixation, smooth pursuit, and saccades dysfunctions), and perceptive problems (reduced visual acuity and contrast sensitivity). While nystagmus and other oculomotor dysfunctions remained stable over time, visual acuity and contrast sensitivity improved; refractive errors worsened and required corrective lenses. Both children showed normal neurodevelopmental and cognitive profile. This report highlights the long-term visual and developmental outcomes of two children exclusively exposed to methadone underlining the possibility of a visual dysfunction and motor coordination disorder. These observations prompt the need to investigate prenatal drug exposure as a cause of congenital nystagmus.

Anticholinergic syndrome: blurred vision and headache.

A young woman presented with blurred vision due to anticholinergic syndrome. We highlight the importance of considering this condition in the context of multiple medications and increased anticholinergic burden. The documented pupil abnormality gives an opportunity to review the syndrome of the reverse (inverse) Argyll Robertson pupil (preserved pupil light response with loss of accommodation). We review other situations in which the reverse Argyll Robertson pupil may occur and its possible mechanism in this case.

Closantel retinal toxicity: Recovery from severe vision loss after corticosteroid therapy.

PURPOSE: To present a relatively rare case of retinal toxicity and consequent severe vision loss due to Closantel ingestion. CASE REPORT: A 37-year-old female presented with sudden painless decrease vision in both eyes. She had no previous history of medical disease and denied any trauma. The patient had accidentally ingested Closantel a few days prior to presentation. Closantel is a veterinary anti-helminthic drug used mainly in livestock. Best corrected visual acuity (BCVA) at presentation was 20/200 bilaterally. There was no relative afferent pupillary defect (RAPD) and red saturation test was normal. Macular optical coherence tomography (OCT) revealed disruption in the outer retinal layer and ellipsoid zone in both eyes. A diagnosis of retinal toxicity due to Closantel was made and the patient was started on 1 mg/kg oral prednisolone acetate. On the 45th day after presentation, her BCVA had improved to 20/20 bilaterally. CONCLUSION: Closantel is a potentially toxic drug causing destruction of the neurosensory retina and visual disturbances. We suggest eye-care personnel awareness regarding the risk of Closantel-induced retinal toxicity and prompt treatment with systemic steroids should be considered.

Ocular toxicity following carboplatin chemotherapy for neuroendocrine tumour of the bladder.

INTRODUCTION: Carboplatin is a commonly used platinum analogue chemotherapeutic agent that is similar to cisplatin but is known to be better tolerated. This case report outlines a case of ocular toxicity following carboplatin chemotherapy used for the management of a neuroendocrine tumour of the bladder. CASE REPORT: A 70-year-old man with a history of neuroendocrine bladder cancer underwent chemotherapy with carboplatin and etoposide. He presented 4 weeks following his fourth chemotherapy cycle with a 1-week history of right eye blurriness. The patient had suffered a similar episode 2 weeks following his third chemotherapy cycle in his left eye. Carboplatin-induced ocular toxicity was suspected and his vision remained stable following cessation of carboplatin chemotherapy. DISCUSSION: Current literature on carboplatin-induced ocular toxicity remains scanty, however, previous cases have reported symptoms beginning 5 days to 2 weeks following carboplatin use. Visual disturbance in the form of altered colour vision, blind spot, blurred vision and metamorphopsia have been reported by previous literature. This case report emphasised a case of bilateral sequential blurring of vision following carboplatin chemotherapy. CONCLUSION: It remains critical for ophthalmologists and oncologists to look out for ocular side effects of chemotherapy due to its devastating effects.

RISK FACTORS OF VISION LOSS AND MULTIPLE RECURRENCES IN MYOPIC MACULAR NEOVASCULARIZATION.

PURPOSE: To investigate the factors associated with maximum visual improvement (peak vision) gain and the risk factors of peak vision loss and multiple recurrences in myopic macular neovascularization undergoing antivascular endothelial growth factor therapy. METHODS: Retrospective study of 310 eyes with active myopic macular neovascularization and median follow-up of 3.5 years. We defined peak vision gain as the maximum best-corrected visual acuity value reached under treatment and peak vision loss as best-corrected visual acuity never scoring as peak vision. We used multiple-event Prentice, Williams, and Peterson models to compute recurrences' incidence and Cox regression to identify risk factors for peak vision gain, peak vision loss, and multiple recurrences. RESULTS: Eyes with worse baseline best-corrected visual acuity {hazard ratio (HR) = 2.59 (95% confidence interval [CI]: 1.63-4.11) for 0.1 logMAR increase, P < 0.001} had higher chance to achieve peak vision. Peak vision was lost in 162 eyes (52%). Older age (HR = 1.22 [95% CI: 1.02-1.43] for 10-year increase, P = 0.02) and recurrences (HR = 1.10 [95% CI: 1.01-1.22] for event, P = 0.04) predicted nonsustained peak vision. Older age (HR = 1.13 [95% CI: 1.04-1.27] for 10-year increase, P = 0.006), larger myopic macular neovascularization (HR = 1.06 [95% CI: 1.01-1.13] for 1-mm 2 increase, P = 0.04), and juxtafoveal location (HR = 1.88 [95% CI: 1.28-2.77] vs. extrafoveal, P = 0.001) predicted multiple recurrences. CONCLUSION: Myopic macular neovascularization eyes lose vision mainly because of multiple recurrences. Patients at risk for recurrences should undergo more attentive monitoring to avoid vision loss.

MERCI: a machine learning approach to identifying hydroxychloroquine retinopathy using mfERG.

PURPOSE: Hydroxychloroquine (HCQ) is an anti-inflammatory drug in widespread use for the treatment of systemic auto-immune diseases. Vision loss caused by retinal toxicity is a significant risk associated with long term HCQ therapy. Identifying patients at risk of developing retinal toxicity can help prevent vision loss and improve the quality of life for patients. This paper presents updated reference thresholds and examines the diagnostic accuracy of a machine learning approach for identifying retinal toxicity using the multifocal Electroretinogram (mfERG). METHODS: A retrospective study of patients referred for mfERG testing to detect HCQ retinopathy. A consecutive series of all patients referred to Kensington Vision and Research Centre between August 2017 and July 2020 were considered eligible. Eyes suspect for other ocular pathology including widespread retinal disease and advanced macular pathology unrelated to HCQ or with poor quality mfERG recordings were excluded. All patients received mfERG testing and Ocular Coherence Tomography (OCT) imaging. Presence of HCQ retinopathy was based on ring ratio analysis using clinical reference thresholds established at KVRC coupled with structural features observed on OCT, the clinical reference standard. A Support Vector Machine (SVM) using selected features of the mfERG was trained. Accuracy, sensitivity and specificity are reported. RESULTS: 1463 eyes of 748 patients were included in the study. SVM model performance was assessed on 293 eyes from 265 patients. 55 eyes from 54 patients were identified as demonstrating HCQ retinopathy based on the clinical reference standard, 50 eyes from 49 patients were identified by the SVM. Our SVM achieves an accuracy of 85.3% with a sensitivity of 90.9% and specificity of 84.0%. CONCLUSIONS: Machine learning approaches can be applied to mfERG analysis to identify patients at risk of retinopathy caused by HCQ therapy.

Probable Methylphenidate-Related Reversible "Visual Snow" in a Child With ADHD.

OBJECTIVES: Visual snow syndrome is relatively a recently recognized neurological entity presenting primarily with positive visual disturbance. Etiology is largely speculative. METHODS: Authors report here on a child case of ADHD that developed a probable visual snow syndrome related to methylphenidate. RESULTS AND CONCLUSIONS: Although remaining rare, prescribers ought to be cognizant of such unusual methylphenidate-related perceptual alterations.

Severe visual loss caused by inhalational methanol poisoning in fireworks production: A report on 3 cases.

BACKGROUND: Workers in fireworks production are mainly at risk for explosion injury. However, there are few reports on the consequences of methanol poisoning in fireworks laborers. CASE PRESENTATION: We report on three patients with visual loss caused by inhalation exposure to high concentrations of methanol, who were engaged in the granulation process of the fireworks manufacturing industry. They presented with severe metabolic acidosis and visual impairments, accompanied by headache, chest tightness, shortness of breath, dizziness, and vomiting. All were diagnosed with acute methanol poisoning. One patient developed bilateral blindness and two patients improved after timely hemodialysis treatment. CONCLUSIONS: These case reports emphasize the risk of methanol poisoning in the fireworks industry or other factories using commercial alcohol with high methanol content. Early hemodialysis intervention and metabolic acidosis correction are crucial for rescuing visual impairment caused by methanol exposure. Awareness and supervision of commercial alcohol use are indispensable for similar industrial processes.

Corneal Allograft Rejection Associated With Herpes Zoster Recombinant Adjuvanted Vaccine.

PURPOSE: The purpose of this article is to report 3 cases of corneal allograft rejection that occurred in temporal proximity to administration of the zoster subunit vaccine (RZV). METHODS: Three cases of corneal transplant rejection that developed after RZV administration were identified. Clinical history, including existence of other risk factors, timing of rejection, corticosteroid therapy at the time of onset of rejection, and course were reviewed. RESULTS: The onset of symptoms occurred 5 weeks after the first RZV dose in 1 patient and 1 and 6 weeks after the second dose in the other 2 patients. Coexisting risk factors included history of endothelial keratoplasty in the fellow eye in 1 patient and previous failure of a penetrating keratoplasty because of rejection in a second patient. The third patient had a history of 1 episode of rejection in a previous graft that resolved and then experienced graft failure over several years. In 2 patients, rejection developed despite relatively high levels of topical steroid therapy: prednisolone acetate 1%, 4 × per day in 1 patient and difluprednate 0.05%, 3 × per day in a second patient. CONCLUSIONS: RZV, which elicits a more robust immune reaction than the zoster live-attenuated vaccine, ZVL, may increase the risk of allograft rejection in immunocompetent patients with preexisting corneal endothelial or penetrating transplants. Based on the available data, it may be reasonable to increase the topical corticosteroid regimen before the first dose, until approximately 3 months after the second dose of ZVL.

Visual impairment and medication safety: a protocol for a scoping review.

BACKGROUND: The number of individuals with a visual impairment in the UK was estimated a few years ago to be around 1.8 million. People can be visually impaired from birth, childhood, early adulthood or later in life. Those with visual impairment are subject to health inequities and increased risk for patient safety incidents in comparison to the general population. They are also known to be at an increased risk of experiencing medication errors compared to those without visual impairment. In view of this, this review aims to understand the issues of medication safety for VI people. METHODS/DESIGN: Four electronic bibliographic databases will be searched: MEDLINE, Embase, PsycInfo and CINAHL. Our search strategy will include search combinations of two key blocks of terms. Studies will not be excluded based on design. Included studies will be empirical studies. They will include studies that relate to both medication safety and visual impairment. Two reviewers (SG and LR) will screen all the titles and abstracts. SG, LR, RM, SCS and PL will perform study selection and data extraction using standard forms. Disagreements will be resolved through discussion or third party adjudication. Data to be collected will include study characteristics (year, objective, research method, setting, country), participant characteristics (number, age, gender, diagnoses), medication safety incident type and characteristics. DISCUSSION: The review will summarise the literature relating to medication safety and visual impairment.