Ocular toxicity associated with anti-HER2 agents in breast cancer: A pharmacovigilance analysis using the FAERS database

Anti-human epidermal growth factor receptor 2 (HER2) agents have exhibited pronounced tumor-inhibitory activity, yet the accompanying ocular toxicity has frequently been underestimated. We aim to conduct a comprehensive comparative analysis of ocular toxicity risk related to various anti-HER2 agents. We executed a retrospective pharmacovigilance investigation based on the FDA Adverse Event Reporting System (FAERS) database, covering the period from Q2 2018 to Q1 2023. The disproportionality analysis was performed to assess ocular toxicity risk. Multivariate logistic regression was implemented to mitigate potential biases. Moreover, the time to onset of ocular toxicity was also evaluated. A total of 3467 ocular adverse event (AE) reports concerning anti-HER2 agents were collected. At the preferred term (PT) level, there were 69 positive signals, among which excessive eye blinking, abnormal sensation in the eye, and asthenopia presented a significant risk. In comparison to tyrosine kinase inhibitors (TKIs), antibody drugs were associated with a broader range of ocular disorders at Standardized MedDRA Queries (SMQ)levels, including conjunctival disorders, corneal disorders, ocular infections, ocular motility disorders, optic nerve disorders, and retinal disorders. In terms of onset time, pertuzumab displayed an earlier onset at 21.5 days, while trastuzumab deruxtecan had the latest at 91.5 days. In summary, our study reveals varying degrees of ocular toxicity related to anti-HER2 agents, with a significantly higher risk observed in antibody drugs. Additionally, novel ocular toxicity signals, not documented in product labels, have been detected. In the future, further research will be necessary to validate our findings.

In silico prediction of ocular toxicity of compounds using explainable machine learning and deep learning approaches

The accurate identification of chemicals with ocular toxicity is of paramount importance in health hazard assessment. In contemporary chemical toxicology, there is a growing emphasis on refining, reducing, and replacing animal testing in safety evaluations. Therefore, the development of robust computational tools is crucial for regulatory applications. The performance of predictive models is heavily reliant on the quality and quantity of data. In this investigation, we amalgamated the most extensive dataset (4901 compounds) sourced from governmental GHS-compliant databases and literature to develop binary classification models of chemical ocular toxicity. We employed 12 molecular representations in conjunction with six machine learning algorithms and two deep learning algorithms to create a series of binary classification models. The findings indicated that the deep learning method GCN outperformed the machine learning models in cross-validation, achieving an impressive AUC of 0.915. However, the top-performing machine learning model (RF-Descriptor) demonstrated excellent performance with an AUC of 0.869 on the test set and was therefore selected as the best model. To enhance model interpretability, we conducted the SHAP method and attention weights analysis. The two approaches offered visual depictions of the relevance of key descriptors and substructures in predicting ocular toxicity of chemicals. Thus, we successfully struck a delicate balance between data quality and model interpretability, rendering our model valuable for predicting and comprehending potential ocular-toxic compounds in the early stages of drug discovery.

Ocular toxicities in chimeric antigen receptor T-cell therapy: a real-world study leveraging FAERS database

Aim: The purpose of this study was to comprehensively explore the ocular toxicity associated with chimeric antigen receptor (CAR) T-cell therapy. Materials & methods: Data were assembled from the US FDA's Adverse Event Reporting System (FAERS) database from 2017 to 2023. Information component and reporting odds ratio methods were used for signal detection in total/categorized CAR T-cell therapy. Results: A total of 17 positive signals (preferred term) were detected, yet none of them were documented in the product information. Some adverse events were with death outcomes and overlapped a lot with cytokine-release syndrome. Conclusion: The ocular adverse events associated with CAR-T cell therapy are noteworthy, and it is imperative to maintain increased alertness and institute early intervention strategies.

Advancements in Retinoblastoma Treatment: Unraveling the Potential of Intravitreal Chemotherapy

Retinoblastoma necessitates urgent attention due to its potential fatality if untreated. Multiple treatment options are available and should be employed according to size, location, and the extent of dissemination. This review emphasizes the need for increased awareness, advanced diagnostic tools, and innovative treatment approaches, especially intravitreal chemotherapy (IVitC) to address the diverse manifestations and aggressive nature of retinoblastoma. Timely diagnosis and commitment to treatment are pivotal, as delays and reluctance to undergo enucleation contribute to unfavorable outcomes. The evolving treatment landscape, spanning from traditional interventions to modern targeted therapies such as intravitreal melphalan, holds promise for improved outcomes. While the intravitreal approach presents challenges, ongoing research aims to establish its definitive role in retinoblastoma treatment. In the treatment of retinoblastoma, IVitC raises considerations about side effects. The risk of tumor spread beyond the eye is rare, emphasising the potential of IVitC in carefully selected cases. Intravitreal injections exhibit fewer local adverse effects compared to intra-arterial chemotherapy, with careful measures reducing significant ocular complications. The evaluation of ocular toxicity, particularly with melphalan, underscores the importance of a nuanced approach to achieve the right balance between therapeutic efficacy and ocular safety. This comprehensive analysis of studies on IVitC and its ocular and systemic complications provides valuable insights for enhanced patient care. The review concludes with a focus on balancing safety and efficacy in local chemotherapeutic drugs, highlighting the need for thoughtful measures and continued research to optimise treatment modalities globally.

Antibody-Drug Conjugates and Ocular Toxicity

Antibody-drug conjugates (ADCs) are a growing class of chemotherapeutic agents for the purpose of treating cancers that often have relapsed or failed first- and second-line treatments. ADCs are composed of extremely potent cytotoxins with a variety of side effects, one of the most significant being ocular toxicity. The available literature describes these toxicities as varying in severity and in incidence, although with disparate methods of evaluation and management. Some of the most common toxicities include microcyst-like epithelial keratopathy and dry eye. We discuss proposed mechanisms of ocular toxicity and describe the reports that mention these toxicities. We focus on ADCs with the most published literature and the most significant effects on ocular tissue. We propose areas for further investigation and possible ideas of future management. We provide a comprehensive look at the reports of ADCs in current literature to better inform clinicians on an expanding drug class.

Transcriptome Profiling of Etridiazole-Exposed Zebrafish (Danio rerio) Embryos Reveals Pathways Associated with Cardiac and Ocular Toxicities

Etridiazole (EDZ) is a thiadiazole-containing fungicide commonly used to control Pythium and Phytophthora spp. Although previous studies have shown that EDZ is teratogenic, the exact molecular mechanisms underlying its toxicity remain unknown. In this study, a zebrafish (Danio rerio; ZF) model was used to explore the molecular pathways associated with EDZ toxicity. The whole transcriptome of ZF embryos exposed to 96 h of EDZ was analyzed, along with developmental abnormalities. EDZ-induced malformations were primarily related to the eyes, heart, and growth of the ZF. Compared to untreated ZF, etridiazole-treated ZF had 2882 differentially expressed genes (DEGs), consisting of 1651 downregulated genes and 1231 upregulated genes. Gene ontology enrichment analysis showed that DEGs were involved in biological processes, such as sensory perception, visual perception, sensory organ development, and visual system development, and showed transmembrane transporter and peptidase regulator activities. Metabolism, phototransduction, aminoacyl-tRNA biosynthesis, MAPK signaling pathway, calcium signaling pathway, and vascular smooth muscle contraction were among the most enriched KEGG pathways. The qPCR analyses of the eight random genes were in good agreement with the transcriptome data. These results suggest several putative mechanisms underlying EDZ-induced developmental deformities in ZF.

Rapid Assessment of Ocular Toxicity from Environmental Contaminants Based on Visually Mediated Zebrafish Behavior Studies

The presence of contaminants in the environment has increased in recent years, and studies have demonstrated that these contaminants have the ability to penetrate the blood-retinal barrier and directly affect the visual systems of organisms. Zebrafish are recognized as an ideal model for human eye diseases due to their anatomical and functional similarities to the human eye, making them an efficient and versatile organism for studying ocular toxicity caused by environmental contaminants in the field of environmental toxicology. Meanwhile, zebrafish exhibit a diverse repertoire of visually mediated behaviors, and their visual system undergoes complex changes in behavioral responses when exposed to environmental contaminants, enabling rapid assessment of the ocular toxicity induced by such pollutants. Therefore, this review aimed to highlight the effectiveness of zebrafish as a model for examining the effects of environmental contaminants on ocular development. Special attention is given to the visually mediated behavior of zebrafish, which allows for a rapid assessment of ocular toxicity resulting from exposure to environmental contaminants. Additionally, the potential mechanisms by which environmental contaminants may induce ocular toxicity are briefly outlined.

Evaluation of Retinal Nerve Fiber Layer and Macular Thickness Pre- and Post-Chemotherapy With Carboplatin and Paclitaxel in Patients With Endometrial and Ovarian Cancer

Background Carboplatin and paclitaxel are two standard chemotherapeutic agents known to cause neurotoxicity. In this study, we aim to evaluate the toxicity of these agents by measuring the peripapillary retinal nerve fiber layer (RNFL) and macular thickness in patients with endometrial and ovarian cancers who are receiving them. Methods A one-year prospective cohort study involving 28 patients who were treated intravenously with carboplatin (200-400 mg/m2) and paclitaxel (175 mg/m2) three-weekly for six cycles was conducted. RNFL and macula thickness were measured using optical coherence tomography (OCT) before the commencement of chemotherapy, after the third cycle, and one month after the sixth cycle. The main outcome measurements were the average RNFL thickness and central subfield thickness of the macula. Results The mean age of the 28 participants was 54.68 years old (standard deviation [SD] 9.03). Eleven had endometrial cancer, while 17 had ovarian cancer. The mean of the average RNFL thickness during baseline pre-chemotherapy was 96.43 µm (SD 11.39). One month after cessation of treatment, the mean RNFL thickness increased to 101.57 µm (SD 13.54). Statistical analysis showed a significant increment in the mean RNFL thickness (p ≤ 0.001), from baseline to after three cycles, and baseline to one month after six cycles of chemotherapy, except the nasal quadrant. The increment of all macular quadrants was statistically significant (p < 0.05) except for central subfield thickness. Conclusion Systemic administration of carboplatin and paclitaxel affected both the peripapillary RNFL and macula thickness. This represents early evidence of subacute subclinical retinal toxicity. OCT can be used as a screening tool to assess peri-chemotherapeutic retinal alterations.

Toxicity to intravitreal melphalan in a patient with retinoblastoma

Objective: Description of melphalan's toxicity in retinoblastoma treatment. Methods: Clinical case report. Results: We presented a case of unilateral retinoblastoma with vitreous seeding at diagnosis, in which the use of intravitreal melphalan produced many adverse reactions. Conclusions: Vitreous seedings have been one of the most important challenges in retinoblastoma treatment. Intravitreal melphalan has achieved the regression of vitreous seedings in a large percentage of cases. It is a safe treatment; however, it can produce toxicity, even with the standard dose of 20-30 µg, which has been poorly documented. Exhaustive follow-up of patients is recommended for an early diagnosis of possible adverse effects. Abbreviations: OS = left eye, RI = magnetic resonance imaging, OCT = optical coherence tomography.

Interaction of systemic drugs causing ocular toxicity with organic cation transporter: an artificial intelligence prediction

Chronic disease patients (cancer, arthritis, cardiovascular diseases) undergo long-term systemic drug treatment. Membrane transporters in ocular barriers could falsely recognize these drugs and allow their trafficking into the eye from systemic circulation. Hence, despite their pharmacological activity, these drugs accumulate and cause toxicity at the non-target site, such as the eye. Since around 40% of clinically used drugs are organic cation in nature, it is essential to understand the role of organic cation transporter (OCT1) in ocular barriers to facilitate the entry of systemic drugs into the eye. We applied machine learning techniques and computer simulation models (molecular dynamics and metadynamics) in the current study to predict the potential OCT1 substrates. Artificial intelligence models were developed using a training dataset of a known substrates and non-substrates of OCT1 and predicted the potential OCT1 substrates from various systemic drugs causing ocular toxicity. Computer simulation studies was performed by developing the OCT1 homology model. Molecular dynamic simulations equilibrated the docked protein-ligand complex. And metadynamics revealed the movement of substrates across the transporter with minimum free energy near the binding pocket. The machine learning model showed an accuracy of about 80% and predicted the potential substrates for OCT1 among systemic drugs causing ocular toxicity - not known earlier, such as cyclophosphamide, bupivacaine, bortezomib, sulphanilamide, tosufloxacin, topiramate, and many more. However, further invitro and invivo studies are required to confirm these predictions.Communicated by Ramaswamy H. Sarma.

Ocular Toxicity Profile of Targeted Cancer Therapy (TCT) at a US Tertiary Cancer Center

PURPOSE

 Targeted cancer therapy (TCT) is a significant advancement in oncology with promising survival improvement in patients with cancer and remarkable effects on various cancers. There is evidence suggesting a connection between specific TCT classes and the occurrence of immune-related adverse events (irAEs). Our study aims to investigate the potential ocular toxicities of different classes of TCT, provide a better understanding of these toxicities, and aid in the future development of screening and management recommendations for ocular irAEs.

DESIGN

 Retrospective observational case series.

PARTICIPANTS

 Only ocular immune-related AEs were included in the study; patients on TCT who received a new ophthalmic diagnosis were seen at the MD Anderson Cancer Center.

METHODS

 Between 2010 and 2019, we retrospectively reviewed the medical records of 6,354 patients on TCT at a large US tertiary cancer center.  Results: The criteria for data analysis were met by 1861 patients. TCT was associated with a wide range of class-specific ocular irAEs. There was a statistically significant correlation between ocular toxicity with polytherapy with a p-value of <0.001. Furthermore, there was a statistically significant correlation between toxicity and BRAF, epidermal growth factor receptor (EGFR), and ICI <0.001, <0.001, and 0.006, respectively.  Conclusion: Our cohort is the most extensive case series in English literature, demonstrating the increased risk of class-specific ocular toxicity associated with TCT, which sheds some light on the importance of developing standardized grading criteria and management guidelines.

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.

Inflammatory Genes Associated with Pristine Multi-Walled Carbon Nanotubes-Induced Toxicity in Ocular Cells

Background

The wide application of multi-walled carbon nanotubes (MWCNTs) in various fields has raised enormous concerns regarding their safety for humans. However, studies on the toxicity of MWCNTs to the eye are rare and potential molecular mechanisms are completely lacking. This study was to evaluate the adverse effects and toxic mechanisms of MWCNTs on human ocular cells.

Methods

Human retinal pigment epithelial cells (ARPE-19) were treated with pristine MWCNTs (7-11 nm) (0, 25, 50, 100 or 200 μg/mL) for 24 hours. MWCNTs uptake into ARPE-19 cells was examined using transmission electron microscopy (TEM). The cytotoxicity was evaluated by CCK-8 assay. The death cells were detected by Annexin V-FITC/PI assay. RNA profiles in MWCNT-exposed and non-exposed cells (n = 3) were analyzed using RNA-sequencing. The differentially expressed genes (DEGs) were identified through the DESeq2 method and hub of which were filtered by weighted gene co-expression, protein-protein interaction (PPI) and lncRNA-mRNA co-expression network analyses. The mRNA and protein expression levels of crucial genes were verified using quantitative polymerase chain reaction (qPCR), colorimetric analysis, ELISA and Western blotting. The toxicity and mechanisms of MWCNTs were also validated in human corneal epithelial cells (HCE-T).

Results

TEM analysis indicated the internalization of MWCNTs into ARPE-19 cells to cause cell damage. Compared with untreated ARPE-19 cells, those exposed to MWCNTs exhibited significantly decreased cell viabilities in a dose-dependent manner. The percentages of apoptotic (early, Annexin V positive; late, Annexin V and PI positive) and necrotic (PI positive) cells were significantly increased after exposure to IC50 concentration (100 μg/mL). A total of 703 genes were identified as DEGs; 254 and 56 of them were, respectively, included in darkorange2 and brown1 modules that were significantly associated with MWCNT exposure. Inflammation-related genes (including CXCL8, MMP1, CASP3, FOS, CXCL2 and IL11) were screened as hub genes by calculating the topological characteristics of genes in the PPI network. Two dysregulated long non-coding RNAs (LUCAT1 and SCAT8) were shown to regulate these inflammation-related genes in the co-expression network. The mRNA levels of all eight genes were confirmed to be upregulated, while caspase-3 activity and the release of CXCL8, MMP1, CXCL2, IL11 and FOS proteins were demonstrated to be increased in MWCNT-treated ARPE-19 cells. MWCNTs exposure also can induce cytotoxicity and increase the caspase-3 activity and the expression of LUCAT1, MMP1, CXCL2, and IL11 mRNA and protein in HCE-T cells.

Conclusion

Our study provides promising biomarkers for monitoring MWCNT-induced eye disorders and targets for developing preventive and therapeutic strategies.

Bromelain protects against cisplatin-induced ocular toxicity through mitigating oxidative stress and inflammation

The aim of this study was to investigate the molecular, biochemical, and histopathological effects of bromelain, which has antioxidant and anti-inflammatory properties, against cisplatin-induced ocular toxicity. The groups were designed as (1) Control, (2) Cisplatin (7 mg/kg, intraperitoneally), (3) Cisplatin + Bromelain (50 mg/kg, orally for 14 consecutive days), (4) Cisplatin + Bromelain (100 mg/kg, orally for 14 consecutive days). The activity of total antioxidant capacity (TAC) and total oxidant status (TOS) and levels of reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), interleukin-1β (IL-1β), IL-10, nuclear factor kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α) and 8-OHdG were measured in ocular tissue. The mRNA expression of NF-κB and Caspase-3 was also evaluated. Also, ocular sections were evaluated histopathologically. Bromelain demonstrated a dose-dependent protective effect in cisplatin-induced toxicity by regulating oxidative stress, inflammation, and tissue damage. Our results suggested that bromelain may be a potential adjuvant that can protect the eye from cisplatin-induced toxicity.

Highlights on Ocular Toxicity of Immune Checkpoint Inhibitors at a US Tertiary Cancer Center

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have improved prognosis in advanced malignancies; however, they may be associated with extensive ocular immune-related adverse events (irAEs) that are sight threatening. Our study aimed to identify the presentation, characteristics, management, and clinical outcomes of ocular irAEs.

METHODS

In this retrospective, observational case series, we reviewed the medical records of 1280 patients at a large US tertiary cancer center between 2010 and 2020.

RESULTS

We identified 130 patients who presented with ocular irAEs (10%) with 69 males (53%) and 61 females (47%). The mean time to toxicity was 6.1 months. Adverse events include corneal toxicity (31%), neuro-ophthalmic (14%), uveitis and scleritis (13%), retinopathy (13%), periocular disorders (11%), and others. IrAEs occurred most frequently with nivolumab (26%). Most ocular irAEs were treated with topical therapy. Advanced cases required systemic corticosteroids and even cessation of ICIs.

CONCLUSION

Our cohort is a large case series highlighting the increased potential of ocular toxicity associated with ICIs. Prompt recognition and management of ocular irAEs can minimize their effect.

Metallic Engineered Nanomaterials and Ocular Toxicity: A Current Perspective

The ocular surface, comprised of the transparent cornea, conjunctiva, and protective tear film, forms a protective barrier defending deeper structures of the eye from particulate matter and mechanical trauma. This barrier is routinely exposed to a multitude of naturally occurring and engineered nanomaterials (ENM). Metallic ENMs are particularly ubiquitous in commercial products with a high risk of ocular exposure, such as cosmetics and sunscreens. Additionally, there are several therapeutic uses for metallic ENMs owing to their attractive magnetic, antimicrobial, and functionalization properties. The increasing commercial and therapeutic applications of metallic ENMs come with a high risk of ocular exposure with poorly understood consequences to the health of the eye. While the toxicity of metallic ENMs exposure has been rigorously studied in other tissues and organs, further studies are necessary to understand the potential for adverse effects and inform product usage for individuals whose ocular health may be compromised by injury, disease, or surgical intervention. This review provides an update of current literature on the ocular toxicity of metallic ENMs in vitro and in vivo, as well as the risks and benefits of therapeutic applications of metallic ENMs in ophthalmology.

Safety, efficacy and delivery of multiple nucleoside analogs via drug encapsulated carbon (DECON) based sustained drug release platform

Acyclovir and similar nucleoside analogs form an essential frontline treatment for various herpesvirus infections of the eye. However, these drugs have low ocular retention when delivered topically and need to be administered several times every day. We have previously demonstrated that acyclovir loaded into activated carbon can be used to significantly decrease dosage frequency in a murine model of ocular infection. In this study, we demonstrate that other nucleoside analogs such as ganciclovir, penciclovir and famciclovir have excellent loading and release profile similar to acyclovir. Similarly we also demonstrate that nucleoside analog loaded carbons termed DECON are effective at very low concentrations in treating active viral infection of human corneal epithelial cells. In this study, using a variety of techniques to evaluate corneal dryness, nerve sensitivity, intraocular pressure, corneal thickness, and somatic inflammation, we report that DECON is well tolerated after administration three times daily over the course of four weeks.

Dramatic Improvement of Severe Cicatricial Ectropion after Discontinuing Long-Term Erlotinib Therapy in a Patient with Lung Cancer

There is no consensus on the choice of systemic and ophthalmic treatment for patients who develop ocular toxicity with erlotinib in the few cases reported previously. Various ocular complications related to erlotinib have been reported, with one of the most serious being corneal perforation. Our patient was at risk of potential corneal perforation because of severe cicatricial ectropion and diffuse punctate corneal epitheliopathy. Therefore, erlotinib treatment was temporarily discontinued with the approval of the oncology department and the patient was closely followed. She was prescribed steroid eye ointment, single-use preservative-free artificial tears, and eye lubricant gel to protect the ocular surface. On day 4 of treatment, the patient’s findings were significantly improved. After 1 week, the cicatricial ectropion had dramatically improved and the patient’s complaints were completely resolved. To our knowledge, there is no case report of a patient with both ocular toxicity after long-term use that shows dramatic improvement with drug cessation, and severe cicatricial ectropion affecting the entire lower eyelid. Here, we described a patient who used erlotinib for 3 years due to non-small cell lung cancer and developed severe cicatricial ectropion which improved dramatically within one week of temporarily discontinuing erlotinib and discussed the possible reasons. Although ocular complications with erlotinib are usually encountered early in treatment, it should be kept in mind that erlotinib-related ocular complications may also arise with long-term use.

Ocular adverse effects of therapeutic biologics

Biological drugs, termed biologics, are medications that contain or are derived from a living organism (human, animal, or microorganism). With new biological agents being approved by the Food and Drug Administration (FDA) every year, clinicians need to know potential ocular adverse effects that are associated with these drugs. This review provides an overview of ocular adverse effects of biological medications used to treat both ophthalmic and non-ophthalmic diseases. We searched PubMed for relevant case reports, case series, reviews, and clinical trials reporting ocular adverse effects caused by biologics. This review was conducted in June 2021 and investigated the drugs listed in the most updated (April 2021) FDA Purple Book Database of Licensed Biological Products. This review focuses on monoclonal antibodies, interleukins, and receptor fusion proteins. We explore ocular side effects of 33 biological drugs, stating whether they are frequent, common, or rare.

Toxic effects of triclocarban on larval zebrafish: A focus on visual dysfunction

Triclocarban (TCC) is considered an endocrine disruptor and shows antagonist activity on thyroid receptors. In view of the report that thyroid hormone signaling mediates retinal cone photoreceptor specification, we hypothesize that TCC could impair visual function, which is vital to wildlife. In order to verify our hypothesis, we assessed alteration in the retinal structure (retinal layer thickness and cell density), visually-mediated behavior, cone and rod opsin gene expression, and photoreceptor immunostaining in zebrafish larvae exposed to TCC at environmentally realistic concentrations (0.16 ± 0.005 µg/L, L-group) and one-fifth of the median lethal concentrations (25.4 ± 1.02 µg/L, H-group). Significant decrease in eye size, ganglion cell density, optokinetic response, and phototactic response can be observed in the L-group, while the thickness of outer nuclear layer, where the cell bodies of cone and rod cells are located, was significantly reduced with the down-regulation of critical opsin gene (opn1sw2, opn1mw1, opn1mw3, opn1lw1, opn1lw2, and rho) expression and rhodopsin immunofluorescence in the H-group. It should be noted that TCC could affect the sensitivity of zebrafish larvae to red and green light according to the results of behavioral and opsin gene expression analysis. These findings provide the first evidence to support our hypothesis that the visual system, a novel toxicological target, is affected by TCC. Consequently, we urgently call for a more in-depth exploration of TCC-induced ocular toxicity to aquatic organisms and even to humans.

The ocular adverse effects of oral drugs

Some commonly prescribed drugs have ocular adverse effects. Many parts of the eye can be affected by oral drugs. Some ocular adverse effects may be reversed with medical or surgical intervention whereas other drugs may cause irreversible loss of vision

The risk of visual loss can be reduced by a number of approaches, including monitoring for ocular toxicity, reducing the drug dose, or stopping the drug and looking for an alternative. This can be supported by good communication between the prescribing clinician and ophthalmologist

Infrequent or delayed ocular adverse effects may not be identified in clinical trials of new drugs. Reporting adverse events is therefore important

Cataract Surgery by Intraoperative Surface Irrigation with 0.25% Povidone-Iodine

Postoperative endophthalmitis after cataract surgery is typically caused by the patient's own conjunctival normal bacterial flora. A three-step approach is recommended to prevent endophthalmitis: (1) "border control" to prevent microorganisms from entering the eye by disinfecting the ocular surface is the most important measure; (2) bacteria that have gained access into the anterior chamber are reduced by irrigation; (3) bacteria remaining in the anterior chamber and vitreous at the end of surgery are controlled by antibacterial drugs. We have devised a method, "the Shimada technique", for irrigating the ocular surface with povidone-iodine, a disinfectant with potent microbicidal effect and established effective and safe concentrations for eye tissues. Povidone-iodine exhibits a bactericidal effect for a wide concentration range of 0.005-10%, but 0.1% povidone-iodine has the highest activity and requires the shortest time of only 15 s to achieve microbicidal effect. When used to irrigate the ocular surface every 20-30 s during cataract surgery, 0.25% povidone-iodine is conceivably diluted to around 0.1%. Irrigation with 0.25% povidone-iodine during cataract surgery significantly reduced bacteria contamination rate in the anterior chamber compared with saline (p = 0.0017) without causing corneal endothelial damage.

Vitreous inflammation and macular edema secondary to perfluoro-n-octane toxicity

Although it is not frequent, residual perfluoro-n-octane elicits an inflammatory response in form of macroscopic white flake-like material on intraocular structures formed by macrophages with intracellular vacuoles containing it. Macular edema could be another manifestation of this entity which, to our knowledge, has not been described so far. We describe an unusual case of intravitreal inflammation and macular edema secondary to the presence of residual perfluoro-n-octane after a surgical intervention of retinal detachment.

Safety and Efficacy of Intravitreal Chemotherapy (Melphalan) to Treat Vitreous Seeds in Retinoblastoma

Background: Active vitreous seeds in eyes with retinoblastoma (Rb) adversely affects the treatment outcome. This study aimed to investigate the safety and efficacy of intravitreal melphalan chemotherapy (IViC) as a treatment for recurrent and refractory vitreous seeds in patients with Rb.

Methods: We used a retrospective non-comparative study of patients with intraocular Rb who had vitreous seeds and were treated by IViC (20–30 μg of melphalan) using the safety-enhanced anti-reflux technique. Tumor response, ocular toxicity, demographics, clinical features, and survival were analyzed.

Results: In total, 27 eyes were treated with 108 injections for recurrent (16 eyes) or refractory (11 eyes) vitreous seeds after failed systemic chemotherapy. A total of 15 (56%) were males, and 20 (74%) had bilateral disease. At diagnosis, the majority (n = 21) of the injected eyes were group D, and n = 6 were group C. Vitreous seeds showed complete regression in 21 (78%) eyes; 100% (n = 10) for eyes with focal seeds; 65% (n = 11/17 eyes) for eyes with diffuse seeds (p = 0.04); 7 (64%) eyes with refractory seeds; and 14 (87%) eyes with recurrent seeds showed complete response (p = 0.37). In total, 16 (59%) eyes developed side effects: retinal toxicity (48%), pupillary synechiae (15%), cataracts (30%), iris atrophy (7%), and retinal and optic atrophy (4%). Only one child was lost to follow-up whose family refused enucleation and none developed orbital tumor recurrence or distant metastasis.

Conclusion: IViC with melphalan is effective (more for focal than diffuse seeding) and a relatively safe treatment modality for Rb that can improve the outcomes of eye salvage procedures. However, unexpected toxicity can occur even with the standard dose of 20–30 μg.

Intravitreal Steroid Treatment for Uveitis Associated with Dabrafenib and Trametinib for Metastatic Cutaneous Melanoma

Purpose: To report a case of bilateral retinal inflammation under long-term therapy with dabrafenib/trametinib for metastatic cutaneous melanoma.Methods: Retrospective chart review.Results: A 59-year-old patient with metastatic cutaneous melanoma diagnosed in 2004 under treatment with dabrafenib/trametinib since 2014 presented to our department with intraretinal hemorrhage and extrafoveal macula edema on the right eye and optic disc swelling on the left eye. The patient did not report visual complaints. After cessation of dabrafenib/trametinib and subconjunctival and intravitreal corticosteroid injections, optic disc swelling on the left eye recovered after 6 months. The macula edema on the right eye was treated with one intravitreal anti-VEGF (vascular endothelial growth factor) injection after encroaching upon the fovea 10 months after initial presentation. The final visual acuity was 20/20 on both eyes.Conclusion: Even after years of treatment with low dose dabrafenib/trametinib, ocular toxicity can develop. Such cases can respond well to intravitreal corticosteroids.

Profile and Management of Toxicity of Selinexor and Belantamab Mafodotin for the Treatment of Triple Class Refractory Multiple Myeloma

Treatment options are limited for multiple myeloma patients who have developed four/five drug-refractory disease. Selinexor (Sel) and belantamab mafodotin (belamaf) were recently approved by the US FDA for treatment of RRMM. The toxicity profile of these drugs is a concern since these agents are used in patients who have already undergone multiple lines of treatment. In this review, we discuss the toxicity profile and strategies for the management of toxicities of Sel and belamaf for the treatment of RRMM. We conducted a comprehensive literature search on PubMed, Embase, Cochrane, and Clinicaltrials.gov using the terms “selinexor”, “belantamab”, “belamaf”, and “multiple myeloma” without applying any limitations based on the date of the study, language, or country of origin. The most common hematological toxicity associated with these two drugs is thrombocytopenia. Cytopenias, constitutional symptoms, gastrointestinal effects, and hyponatremia are the major toxicities of Sel. Keratopathy and anemia are the major toxicities of belamaf. Treatment modifications and dose interruption are usually needed when side effects are more than grade II. As these are newer drugs with limited data, continuous surveillance and monitoring are warranted during the treatment course with early mitigation strategies.

Effects of Achillea millefolium on cisplatin induced ocular toxicity: an experimental study

Aim: Cisplatin is a widely used and highly effective anti-cancer agent and one of the limiting side effects of cisplatin is ocular toxicity. Achillea millefolium, also known as yarrow, is a plant that has been used for many years to treat various health problems including chemotherapy-related toxicities. Methods: The present investigation was designed to evaluate the biochemical, molecular and histopathological effects of Achillea Millefolium on cisplatin-induced oxidative and inflammatory ocular damage in rats. Twenty-four adult male rats were assigned randomly to four groups (n = 6) as (1) control, (2) cisplatin (7 mg/kg, intraperitoneally), (3) Cisplatin + Achillea millefolium (200 mg/kg, orally for 14 consecutive days), (4) Cisplatin + Achillea millefolium (400 mg/kg, orally for 14 consecutive days). Levels of total antioxidant capacity and total oxidant status, SOD, MDA, IL-1β, and IL-10 were measured in ocular tissue. The mRNA expressions of TNF-α, nuclear factor kappa B and Caspase-3 were evaluated. Also, ocular sections were evaluated histopathologically.Results: Achillea Millefolium upregulated ocular antioxidant enzymes and downregulated inflammation. The SOD activity and total antioxidant capacity increased whereas total oxidant status and MDA levels decreased significantly at high dose group. High dose Achillea millefolium treatment reduced the IL-1β concentrations, whereas IL-10 levels increased significantly in that group. Moreover, we observed that Achillea millefolium restored ocular histopathological structure and significantly suppressed apoptosis by reducing the expression of Caspase-3.Conclusion: Collectively, our results suggest that Achillea millefolium have protective effects against cisplatin-induced ocular toxicity and is a promising adjuvant therapy with the potential to prevent cisplatin related ocular toxicity.

Ocular Toxicity of Belantamab Mafodotin, an Oncological Perspective of Management in Relapsed and Refractory Multiple Myeloma

Belantamab mafodotin (belamaf), an antibody-drug conjugate approved for the treatment of relapsed and refractory multiple myeloma (RRMM), is an anti B-cell maturation antigen (BCMA) agent. DREAMM-1, a first in-human trial of belamaf, reported several ocular toxicities requiring dose adjustments, dose delays and treatment discontinuations. In DREAMM-1, 53% of patients in part-1 and 63% of patients in part-2 had ocular toxicity. Similarly, 73% of patients in DREAMM-2 had keratopathy (71% in 2.5 mg/kg versus 75% in 3.4 mg/kg) with the most common symptoms being blurred vision and dry eyes. Ocular toxicity of belamaf is attributed to microtubule-disrupting monomethylauristatin-F (MMAF), a cytotoxic payload of the drug that causes an off-target damage to the corneal epithelial cells. Ocular adverse events (AEs) of belamaf are more frequent at higher doses compared with lower doses. Higher belamaf dose, history of dry eyes and soluble BCMA are associated with increased risk of corneal toxicity. Absence of ocular symptoms does not exclude the possibility of belamaf-induced ocular toxicity, so patients need slit lamp and Snellen visual acuity testing to detect microcytic-like epithelial changes and visual decline. Corticosteroid eyes drops for 4-7 days prior to belamaf dose do not prevent ocular AEs and may cause steroid-related AEs instead. Keratopathy and Visual Acuity scale (KVA) is recommended to document the severity of belamaf-induced ocular toxicity and make treatment adjustments. Management of toxicity includes dosage modifications, treatment interruption or discontinuations and preservative-free artificial tears along with close ophthalmology and hematology-oncology follow-ups.

Ocular side effects of checkpoint inhibitors

The incidence and impact of ocular side effects in patients treated with checkpoint inhibitors are not clearly defined. We reviewed prospective phase III clinical trials of checkpoint inhibitors applied in lung cancer, renal cell cancer, and melanoma. Case reports of the occurrence of ocular toxicities in patients receiving immune checkpoint inhibitors were also included. Of the 35 articles corresponding to phase III clinical trials with checkpoint inhibitors, ocular toxicity was described in four. Forty-six clinical cases of ocular toxicity after therapy with checkpoint inhibitors have been reported. The most frequently described ocular toxicities are uveitis, inflammatory orbital disease, and alterations of the ocular surface. Ocular toxicity is underestimated in checkpoint inhibitors clinical trials. Early ophthalmic examination and treatment with corticosteroids may improve the visual prognosis in these patients.

Retinal and Lens Degeneration in New Zealand White Rabbits Administered Intravitreal TSG-6 Link Domain-Rabbit FAb Fusion Proteins

Fusion of biologic therapeutics to hyaluronic acid binding proteins, such as the link domain (LD) of Tumor necrosis factor (TNF)-Stimulated Gene-6 (TSG-6), is expected to increase vitreous residence time following intravitreal injection and provide for long-acting delivery. The toxicity of a single intravitreal dose of free TSG-6-LD and fusion proteins of TSG-6-LD and a nonbinding rabbit antibody fragment (RabFab) were assessed in New Zealand White rabbits. Animals administered free TSG-6-LD exhibited extensive lens opacities and variable retinal vascular attenuation, correlated with microscopic findings of lens and retinal degeneration. Similar but less severe findings were present in animals dosed with the RabFab-TSG-6-LD fusion proteins. In-life ocular inflammation was noted in all animals from 7-days postdose and was associated with high anti-RabFab antibody titers in animals administered fusion proteins. Inflammation and retinal degeneration were multifocally associated with evidence of retinal detachment, and hypertrophy and migration of vimentin, glial fibrillary acidic protein, and glutamine synthetase positive Müller cells to the outer nuclear layer. Further assessment of alternative hyaluronic acid binding protein fusions should consider the potential for retinal degeneration and enhanced immune responses early in development.

Neuroanatomy and Sampling of Central Projections for the Visual System in Mammals Used in Toxicity Testing

Visual system toxicity may manifest anywhere in the visual system, from the eye proper to the visual brain. Therefore, effective screening for visual system toxicity must evaluate not only ocular structures (ie, eye and optic nerve) but also multiple key brain regions involved in vision (eg, optic tract, subcortical relay nuclei, and primary and secondary visual cortices). Despite a generally comparable pattern across species, the neuroanatomic organization and function of the visual brain in rodents and rabbits exhibit appreciable differences relative to nonrodents. Currently recognized sampling practices for general toxicity studies in animals, which are based on easily discerned external neuroanatomic landmarks and guided by extant stereotaxic brain atlases, typically will permit histopathologic evaluation of many brain centers involved in visual sensation (eg, optic chiasm, optic tract, dorsal lateral geniculate nucleus, primary and secondary visual cortices) and often some subcortical brain nuclei involved in light-modulated nonvisual activities needed for visual attention and orientation (eg, rostral colliculus in quadrupeds, termed the superior colliculus in bipeds; several cranial nerve nuclei). Pathologic findings induced by toxicants in the visual brain centers are similar to those that are produced in other brain regions.

COVID-19 Pandemic - A Narrative Review of the Potential Roles of Chloroquine and Hydroxychloroquine

BACKGROUND

Chloroquine (CQ) and hydroxychloroquine (HCQ) are old drugs used against malaria, rheumatism, inflammation in the joints, lupus, among others. These drugs showed positive results in preliminary scientific research for treatment of the severe acute respiratory syndrome coronavirus (SARS-CoV-2). Since the studies with CQ and HCQ are initial with small patient populations, it is not yet known whether there are adverse effects from the use of CQ and HCQ for patients infected with the coronavirus.

OBJECTIVES

The aim of this study was to evaluate the evidence regarding the efficacy and safety of CQ and HCQ used against viral infection caused by SARS-CoV-2.

STUDY DESIGN

This is a narrative review of the traditional prescriptions of CQ and HCQ efficacy and adverse effects as well as their employment for coronavirus disease 2019 (COVID-19).

SETTING

In vitro and clinical studies comparing the antiviral efficacy and adverse effect profile of CQ and HCQ against COVID-19 in adult patients were evaluated.

METHODS

A systemic search of reviews, including in vitro and clinical trial studies in English focusing on CQ and HCQ effects and adverse effects against COVID-19 in the adult patient population from PubMed was performed. It included studies reporting chloroquine and hydroxychloroquine effects and adverse effects against COVID-19.

RESULTS

A total of 42 articles published between 2004 and April 2020 were reviewed for therapeutic use of CQ and HCQ. Both these drugs showed a significant in vitro potential against coronavirus. Many studies for clinical use of CQ and HCQ showed that patients presented adverse reactions on high doses.

LIMITATIONS

Clinical studies have some methodology shortcomings, such as lack of information about the treatment and small number of experimental patients, leading to a misinterpretation of the data. Besides, there are few clinical studies with a limited sample size. Moreover, most of them did not present control groups, and some patients had died during these protocols.

DISCUSSION

Despite both CQ and HCQ in vitro antiviral evidence, clinically, both drugs, either alone or combined with other medications, may increase the risk of cardiac arrhythmias, leading to cardiac arrest and sudden death. Besides, a lot of uncertainty still remains, such as starting administration period, dose prescribed, length of treatment, patients' condition, concomitant drug use, among others.

CONCLUSION

From the studies reviewed, it is not possible to state the precise efficacy and safety of CQ and HCQ use in the treatment of COVID-19 at any time in the course of the disease. Future studies are warranted.

Bilateral subfoveal serous detachment following Cisplatin chemotherapy

A 74-year-old gentleman with a background of metastatic pancreatic neuroendocrine tumour on combination chemotherapy of Cisplatin and Etoposide presented with a 3-week history of bilateral visual loss. Snellen visual acuity was right 6/9 and left 6/60. Fundus examination revealed clear media with isolated macular oedema in both eyes. Optical coherence tomography of the maculae showed localised bilateral subfoveal serous detachments. Cisplatin was thought to be the causative agent and was withheld following discussion with the treating Oncology team. Eight weeks after withholding Cisplatin, his vision improved with complete resolution of the subretinal fluid. To the authors' knowledge, this is the first report to have illustrated bilateral subfoveal serous detachment caused by Cisplatin which resolved completely with cessation of offending drug.

Optic neuritis induced by 5-fluorouracil chemotherapy: Case report and review of the literature

Introduction

For over 50 years, 5-Fluorouracil has played a critical role in the treatment of numerous malignancies, including colorectal cancer. Ocular side effects are uncommon and include blurred vision, conjunctivitis, excessive lacrimation and keratitis.

Case report

We report a 57-year-old male with metastatic colorectal cancer who had received extensive chemotherapy with 5-Fluorouracil-based regimens for over 12 months. Following his seventh cycle of cetuximab/FOLFIRI, he developed acute onset global headache, nausea and loss of vision in the right eye. After detailed investigations, including ophthalmologic and neurologic consultations, a diagnosis of optic neuritis was made.

Management and outcome

Chemotherapy was ceased immediately, and intravenous methylprednisolone (1 g) daily for five days was commenced. His headache resolved and vision started to improve within 24 h. Three weeks after completion of corticosteroids, constriction of the right visual field had fully resolved.

Discussion

Atypical optic neuritis is an inflammatory optic neuropathy that can be caused by ischaemia, mechanical compression, nutritional deficiency, toxins and drugs. Drug-induced optic neuritis, while rare, is associated with cytotoxic medications including methotrexate, cisplatin, carboplatin, vincristine and paclitaxel. There have only been five previous case reports implicating 5-Fluorouracil in the development of optic neuropathy. The likelihood of the adverse drug reaction due to 5-Fluorouracil was assessed using the Naranjo algorithm. A score of +7 indicates probable causality. Clinicians should be alert to this potential ocular toxicity in order to initiate prompt cessation of treatment and early ophthalmology referral to prevent visual loss and damage to ocular structures.

Neurovascular Organotypic Culture Models Using Induced Pluripotent Stem Cells to Assess Adverse Chemical Exposure Outcomes

Introduction: Human-induced pluripotent stem cells (iPSCs) represent a promising cell source for the construction of organotypic culture models for chemical toxicity screening and characterization. Materials and Methods: To characterize the effects of chemical exposure on the human neurovasculature, we constructed neurovascular unit (NVU) models consisting of endothelial cells (ECs) and astrocytes (ACs) derived from human-iPSCs, as well as human brain-derived pericytes (PCs). The cells were cocultured on synthetic poly(ethylene glycol) (PEG) hydrogels that guided the self-assembly of capillary-like vascular networks. High-content epifluorescence microscopy evaluated dose-dependent changes to multiple aspects of NVU morphology. Results: Cultured vascular networks underwent quantifiable morphological changes when incubated with vascular disrupting chemicals. The activity of predicted vascular disrupting chemicals from a panel of 38 compounds (U.S. Environmental Protection Agency) was ranked based on morphological features detected in the NVU model. In addition, unique morphological neurovascular disruption signatures were detected per chemical. A comparison of PEG-based NVU and Matrigel^™-based NVU models found greater sensitivity and consistency in chemical detection by the PEG-based NVU models. Discussion: We suspect that specific morphological changes may be used for discerning adverse outcome pathways initiated by chemical exposure and rapid mechanistic characterization of chemical exposure to neurovascular function. Conclusion: The use of human stem cell-derived vascular tissue and PEG hydrogels in the construction of NVU models leads to rapid detection of adverse chemical effects on neurovascular stability. The use of multiple cell types in coculture elucidates potential mechanisms of action by chemicals applied to the model.

Reversible Ocular Toxicity of Oxaliplatin: A Case Report

Oxaliplatin, a platinum-based chemotherapy agent, is commonly used in the treatment of various malignancies. Common adverse effects involve neurological, hematological, gastrointestinal system, and hypersensitivity, and rarely ocular changes have also been reported. We describe the case of a 71-year-old male, who developed reversible ocular toxicity after receiving oxaliplatin for treatment for pancreatic cancer.

Ocular dysfunctions and toxicities induced by antiepileptic medications: Types, pathogenic mechanisms, and treatment strategies

INTRODUCTION

Ocular dysfunctions and toxicities induced by antiepileptic drugs (AEDs) are rarely reviewed and not frequently received attention by treating physicians compared to other adverse effects (e.g. endocrinologic, cognitive and metabolic). However, some are frequent and progressive even in therapeutic concentrations or result in permanent blindness. Although some adverse effects are non-specific, others are related to the specific pharmacodynamics of the drug. Areas covered: This review was written after detailed search in PubMed, EMBASE, ISI web, SciELO, Scopus, and Cochrane Central Register databases (from 1970 to 2019). It summarized the reported ophthalmologic adverse effects of the currently available AEDs; their risks and possible pathogenic mechanisms. They include ocular motility dysfunctions, retinopathy, maculopathy, glaucoma, myopia, optic neuropathy, and impaired retinal vascular autoregulation. In general, ophthalmo-neuro- or retino-toxic adverse effects of AEDs are classified as type A (dose-dependent), type B (host-dependent or idiosyncratic) or type C which is due to the cumulative effect from long-term use. Expert opinion: Ocular adverse effects of AEDs are rarely reviewed although some are frequent or may result in permanent blindness. Increasing knowledge of their incidence and improving understanding of their risks and pathogenic mechanisms are crucial for monitoring, prevention, and management of patients' at risk.

From the Cover: Inhibitors of Nicotinamide Phosphoribosyltransferase Cause Retinal Damage in Larval Zebrafish

Nicotinamide phosphoribosyltransferase (NAMPT) has been investigated as a target for oncology because it catalyzes a rate-limiting step in cellular energy metabolism to produce nicotinamide adenine dinucleotide. Small molecule inhibitors of NAMPT have been promising drug candidates but preclinical development has been hindered due to associated retinal toxicity. Here we demonstrate that larval zebrafish can predict retinal toxicity associated with this mechanism revealing an attractive alternative method for identifying such toxicities. Zebrafish permit higher throughput testing while using far lower quantities of test article compared with mammalian systems. NAMPT inhibitor-associated toxicity manifested in zebrafish as a loss of response to visual cues compared with auditory cues. Zebrafish retinal damage associated with NAMPT inhibitor treatment was confirmed through histopathology. Ranking 6 NAMPT inhibitors according to their impact on zebrafish vision revealed a positive correlation with their in vitro potencies on human tumor cells. This correlation indicates translatable pharmacodynamics between zebrafish and human NAMPT and is consistent with on-target activity as the cause of retinal toxicity associated with NAMPT inhibition. Together, these data illustrate the utility of zebrafish for identifying compounds that may cause ocular toxicity in mammals, and, likewise, for accelerating development of compounds with improved safety margins.

Solid lipid nanoparticles for ocular delivery of isoniazid: evaluation, proof of concept and in vivo safety & kinetics

AIM

Evaluation of solid lipid nanoparticles (SLNs) for ocular delivery of isoniazid (INH).

MATERIALS & METHODS

INH-SLNs were characterized for morphological, thermal, crystalline and nuclear magnetic resonance properties. In vitro release and ex vivo corneal permeability of INH-SLNs was also evaluated. Proof-of-concept uptake studies were performed in corneal and conjunctival cell lines and in vivo in rat eye using fluorescein-labeled SLNs. Antimycobacterial activity of INH-SLNs was confirmed. In vivo aqueous humor pharmacokinetics, toxicity and tolerance was performed in rabbit/rat eye.

RESULTS

INH-SLNs showed extended release (48 h), enhanced corneal permeability (1.6-times), five-times lower MIC, significant in vitro and in vivo uptake of fluorescein-labeled SLNs, 4.2-times ocular bioavailability (area under the curve) and in vivo acute and repeat dose safety.

CONCLUSION

INH-SLNs are an effective ocular delivery system.

Ocular toxicity due to colours used during holi celebration in India: correlation of clinical findings with the anterior segment OCT

PURPOSE

To correlate the anatomical extent of ocular surface toxicity due to colours using anterior segment optical coherence tomography (ASOCT) with the clinical findings.

METHODS

Patients presenting to our emergency department with ocular colour toxicity during the Holi festival celebrations from March 2 2018 to March 5 2018 were assessed for any adnexal, conjunctival, corneal, and anterior chamber findings, as well as findings on anterior segment optical coherence tomography.

RESULTS

A total of 21 patients were observed. The average age was 23 years with 16 patients being male (76.19%). Bilateral ocular involvement was more common (13 patients, 61.90%). Clinically, the corneal changes included localized punctate epitheliopathy (type I) in 12 patients (57.14%) and diffuse punctate epitheliopathy admixed with a variable sized epithelial defect (type II) in the other 9 patients (42.85%). The visual acuity among the former group varied from 6/6 to 6/9, whereas for the latter, it ranged from 6/12 to 6/24. On ASOCT in both the types, the superficial stromal involvement was noted up to 60 microns. Interestingly in two patients with type II corneal involvement, anterior segment involvement was noted in the form of staining of the lens capsule and dense anterior chamber inflammation.

CONCLUSIONS

Ocular toxicity due to colours used during Holi mainly involves the surface epithelium and the superficial stroma. This was observed clinically and also confirmed on ASOCT. The colour can rarely diffuse into the anterior chamber causing an inflammatory reaction and staining of the lens capsule. However, if managed appropriately, vision-threatening complications can be averted.

Ocular Drug Distribution and Safety of a Noninvasive Ocular Drug Delivery System of Dexamethasone Sodium Phosphate in Rabbit

PURPOSE

To determine the ocular toxicity, systemic exposure, and amounts of dexamethasone sodium phosphate (DSP) in ocular tissues after administration of DSP with the Visulex system (DSP-Visulex).

METHODS

DSP-Visulex was applied onto healthy rabbit eyes. DSP concentrations (4%, 8%, 15%, and 25%) and treatment durations (5, 10, and 20 min) were evaluated for the amounts of DSP in the ocular tissues and in plasma after single administrations of DSP-Visulex. The drug in eye tissues and plasma was analyzed by high-performance liquid chromatography-UV/VIS and by liquid chromatography-mass spectrometry, respectively. The safety and tolerability were ascertained based on clinical observations and histopathological examinations from repeat weekly DSP-Visulex treatments (4%, 8%, 15%, and 25% for 20 min) for 12 weeks.

RESULTS

Significant amounts of DSP (ie, higher than 1 μg/g) were found in the anterior chamber, retina-choroid, cornea, vitreous, conjunctiva, and sclera after single applications of DSP-Visulex. The DSP concentrations in the ocular tissues and in plasma increased with increased DSP concentrations in the Visulex applicator and with increased application times. Systemic DSP was rapidly detected. The plasma half-life was 2-3 h. C_max was 148 and 1,844 ng/mL, and the area under the plasma drug concentration versus time curve (AUC) was 418 and 3,779 ng · h/mL for the low dose (4% DSP-Visulex for 5 min) and the high dose (15% DSP-Visulex for 20 min), respectively. Ocular findings over 12 weeks were mostly conjunctival injection and eye discharge. These were transient and mild. Histopathological examinations indicated the eyes to be normal.

CONCLUSIONS

DSP can be administered safely and effectively into the rabbit eye with the Visulex system. Treatment duration and DSP concentration are important factors in achieving therapeutic levels. Repeat applications of DSP-Visulex are safe and well tolerated for weekly administrations over 4-12 weeks. DSP-Visulex has clinical potential for the noninvasive treatment of ocular diseases.

A novel lipid prodrug strategy for sustained delivery of hexadecyloxypropyl 9-[2-(phosphonomethoxy)ethyl]guanine (HDP-PMEG) on unwanted ocular proliferation

Proliferative vitreoretinopathy (PVR) is a blinding eye disease and there is no effective pharmacological measure to prevent PVR development. The difficulty comes from lack of potent antiproliferative agent and lack of sustained delivery to cover high-risk time window for PVR to develop. Lipid prodrug of PMEG, hexadecyloxypropyl 9-[(2-phosphonomethoxy)ethyl]guanine (HDP-PMEG), was prepared and was evaluated as a pharmacological adjuvant to surgical management of PVR. A dose-escalation study determined that the highest nontoxic dose for intravitreal use in pigmented rabbits was 3 µg per eye. The genotoxicity of HDP-PMEG was harnessed as a perioperative preventative measure against PVR in a rabbit eye model while the sustained intravitreal pharmacological effect was evaluated on a laser-induced fibrovascular model in rat eye. After intravitreal 3 µg, HDP-PMEG particles in the rabbit vitreous was visible for at least 6 weeks. A single 50-min intravitreal infusion of HDP-PMEG demonstrated significant inhibition of PVR formation when compared with the eyes infused with only BSS (BSS vs. HDP-PMEG: estimate = 1.14, OR = 3.1, p = .027). A single intravitreal 104 ng (equivalent to 3 µg for rabbit eye) of HDP-PMEG significantly inhibit laser-induced fibrovascular proliferation in rat eye by 55% (least square mean pixel, BSS = 4763569.5 vs. HDP-PMEG = 2148129.7, p < .0001, generalized estimating equation [GEE]). Retinal fluorescein angiography showed the odds for BSS intervened eyes to have higher-rated FA leaking grades were 38.5 times compared with HDP-PMEG treated eyes (p < .0001, GEE). Our study results indicate that single intravitreal HDP-PMEG may be a promising ocular drug delivery as a perioperative intervention to prevent PVR reoccurrence following primary surgical management.

Analysis of Draize eye irritation testing and its prediction by mining publicly available 2008-2014 REACH data

Public data from ECHA online dossiers on 9,801 substances encompassing 326,749 experimental key studies and additional information on classification and labeling were made computable. Eye irritation hazard, for which the rabbit Draize eye test still represents the reference method, was analyzed. Dossiers contained 9,782 Draize eye studies on 3,420 unique substances, indicating frequent retesting of substances. This allowed assessment of the test's reproducibility test based on all substances tested more than once. There was a 10% chance of a non-irritant evaluation given after a prior severe-irritant result as given by UN GHS classification criteria. The most reproducible outcomes were the results negative (94% reproducible) and severe eye irritant (73% reproducible). To evaluate whether other GHS categorizations predict eye irritation we built a dataset of 5,629 substances (1,931 'irritant' and 3,698 'non-irritant'). The two best decision trees with up to three other GHS classifications resulted in balanced accuracies of 68% and 73%, i.e., in the rank order of the Draize rabbit eye test itself, but both use inhalation toxicity data ("May cause respiratory irritation"), which is not typically available. Next, a dataset of 929 substances with at least one Draize study was mapped to PubChem to compute chemical similarity using 2D conformational fingerprints and Tanimoto similarity. Using a minimum similarity of 0.7 and simple classification by the closest chemical neighbor resulted in balanced accuracy from 73% over 737 substances to 100% at a threshold of 0.975 over 41 substances. This represents a strong support of read-across and (Q)SAR approaches in this area.

The effect of thiamine pyrophosphate on ethambutol-induced ocular toxicity

CONTEXT

Ethambutol-induced retinal oxidative damage in patients with tuberculosis is still not being adequately treated. The protective effect of thiamine pyrophosphate against oxidative damage in some tissues has been reported, but no information on the protective effects of thiamine pyrophosphate against ethambutol-induced oxidative retinal damage has been found in the medical literature.

OBJECTIVE

The objective is to investigate whether thiamine pyrophosphate has a protective effect against oxidative retinal damage in rats induced by ethambutol.

MATERIALS AND METHODS

Experimental animals divided into four groups (n = 10): the healthy group (HG), the ethambutol control group (EMB), thiamine + ethambutol group (Thi-EMB) and thiamine pyrophosphate + ethambutol group (TPP-EMB). The rats in the TPP-EMB and Thi-EMB groups were administered thiamine pyrophosphate and thiamine, respectively, at doses of 20 mg/kg intraperitoneally. Distilled water was administered intraperitoneally to the HG and the EMB groups as a solvent in the same volumes. One hour after drug injection, 30 mg/kg ethambutol was administered via an oral gavage to the TPP-EMB, Thi-EMB and EMB groups. This procedure was repeated once a day for 90 days. At the end of this period, all rats were euthanized under high-dose thiopental sodium anesthesia, and biochemical and histopathological investigations of the retinal tissue were performed.

RESULTS

Malondialdehyde (MDA) and DNA damage product 8-hydroxyguanine levels were significantly lower in the retinal tissue of TPP-EMB and HG groups compared to those of the Thi-EMB and EMB groups, and total glutathione (tGSH) was also found to be higher. In addition, severe retinal tissue vascularization, edema and loss of ganglion cells were observed in the Thi-EMB and EMB groups, whereas histopathological findings for the TPP-EMB group were observed to be close to normal.

DISCUSSION AND CONCLUSION

These findings suggest that thiamine pyrophosphate protects retinal tissues from ethambutol-induced oxidative damage, and thiamine does not. This positive effect of thiamine pyrophosphate may be useful in the prevention of ocular toxicity that occurs during ethambutol use.

Critical appraisal of alternative irritation models: three decades of testing ophthalmic pharmaceuticals

BACKGROUND

Testing ocular tolerability of ocular pharmaceuticals is an essential regulatory requirement. The current approved reference model (gold standard) for ocular irritation testing is the Draize test. However this method is subjective and involves using live animals, hence the need to develop alternative in vitro and ex vivo testing strategies.

SOURCE OF DATA

Pubmed, Science Direct, Scopus, Google Scholar, Medline, Current Content, Web of Science and validation reports from international regulatory bodies; The Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) and European Centre for the Validation of Alternative Methods (ECVAM) were searched for in vitro alternatives.

AREA OF AGREEMENT

Whilst no single in vitro test can effectively replace the Draize eye irritation test, regulatory bodies and cosmetic/pharmaceutical industries agree that there is a need for in vitro alternatives with validated endpoints to evaluate pharmaceutical ingredients and finished eye products.

AREA OF CONTROVERSY

There is no single in vitro test / assay that can predict the ocular irritation potential of mild to moderate test substances.

AREA TIMELY FOR DEVELOPING RESEARCH

This review provides a critical appraisal of the selected in vitro and ex vivo ocular toxicity models recommended by international regulatory bodies. These include cytotoxicity methods, biochemical systems and ex vivo assays. The latter are approved by ECVAM as in vitro alternatives for the well-known Draize test. Hen's egg test-chorioallantoic membrane and the isolated rabbit eye test are also accepted by regulatory agencies in France, Germany, the Netherlands and the UK. A combination of ex vivo assays along with histological examination of excised bovine cornea can predict the conjunctival and corneal tolerability and cover a wider range of ocular pharmaceutical substances.

Bilateral maculopathy associated with sertraline

OBJECTIVE

We report a rare case of bilateral maculopathy that developed with the initiation of sertraline.

METHODS

We conducted a case report and review of the literature.

RESULTS

A 23-year-old man rapidly developed maculopathy with associated visual blurring after the initiation of sertraline. Treatment was ceased with the patient subsequently reporting mild improvement in visual symptoms.

CONCLUSIONS

Maculopathy associated with sertraline use has yet to be established and recognized as an adverse side effect. With only one previous reported case in the literature, this condition requires further awareness.

Usefulness of optical coherence tomography to detect central serous chorioretinopathy in monkeys

Many systemic drugs can induce ocular toxicity and several ocular side-effects have been identified in clinical studies. However, it is difficult to detect ocular toxicity in preclinical studies because of the lack of appropriate evaluation methods. Optical coherence tomography (OCT) is useful because it can provide real-time images throughout a study period, whereas histopathology only provides images of sacrificed animals. Using OCT alongside histopathology, attempts were made to find effective approaches for screening of drug-induced ocular toxicity in monkeys. Such approaches could be used in preclinical studies prior to human trials. Six male cynomolgus monkeys (Macaca fascicularis Raffles) were orally administered one of six candidate MAPK/ERK kinase (MEK) inhibitors. Central serous chorioretinopathy, a known side-effect of such inhibitors, was identified in four monkeys by OCT. Artifacts generated during tissue processing meant that histopathology could not detect edematous changes. Thus, OCT is a useful tool to detect ocular toxicity which cannot be detected by histopathology in preclinical studies.

Ocular toxicity of benzalkonium chloride homologs compared with their mixtures

This study was performed to assess the in vivo ocular toxicity of benzalkonium chloride (BAK) homologs compared with commercially available BAK (BAK mixture) and to assess the ocular toxicity of BAK homolog after repeated ocular application. Rabbit eyes were examined by ophthalmology and scanning electron microscopy (SEM) after 10 applications of BAK homologs with C12 (C12-BAK) and C14 (C14-BAK) alkyl chain lengths and a BAK mixture at concentrations of 0.001% (w/v), 0.003% (w/v), 0.005% (w/v), 0.01% (w/v) and 0.03% (w/v). The ocular toxicity of C12-BAK to rabbit eyes was examined by ophthalmology and histopathology after repeated ocular application for 39 weeks. In addition, the antimicrobial activities of C12-BAK and C14-BAK against A. niger, S. aureus and P. aeruginosa were assessed. Ocular toxicity of C12-BAK was less than those of the BAK mixture and C14-BAK. No ocular toxicity was noted after ocular application of 0.01% C12-BAK to rabbits for 39 weeks. C12-BAK showed antimicrobial activities at a concentration of 0.003%. These results suggest that the use of C12-BAK to replace BAK mixture as a preservative in ophthalmic solutions should be considered in order to reduce the incidence of the corneal epithelial cell injury induced clinically by BAK.