OPTICAL COHERENCE TOMOGRAPHY FINDINGS IN PRESUMED VETERINARY ANTHELMINTIC DRUG-INDUCED RETINAL TOXICITY: A Glimpse into Underlying Mechanism.

PURPOSE: To report optical coherence tomography findings of presumed veterinary anthelmintic drugs (VADs)-induced retinal toxicity that may aid in understanding potential pathogenic mechanisms. METHODS: This is a retrospective observational case series analysis of patients with vision abnormalities following the accidental or intentional consumption of veterinary anthelmintic drugs. All cases underwent a thorough ophthalmological examination. Moreover, medical records, as well as the initial and follow-up optical coherence tomography images, were thoroughly scrutinized. RESULTS: Four patients were identified (3 men; mean [range] age, 36.5 [22-52] years). Each patient overdosed on one or two of the following VADs: closantel, triclabendazole, praziquantel, pyrantel pamoate, and niclofolan. The most characteristic optical coherence tomography finding was diffuse, granular, hyperreflective lesions throughout the outer retina, which were initially identified in the ellipsoid zone in two cases. At follow-up, optical coherence tomography exhibited regression of hyperreflective lesions and extensive loss of the outer retinal elements in two patients. In addition, the subfoveal outer retinal layers may be partially preserved. CONCLUSION: Some veterinary anthelmintic drugs could be detrimental to the human retina if overdosed, resulting in visual disturbances. Optical coherence tomography revealed the mitochondria-enriched ellipsoid zone where outer retinal damage first appeared on, implying that these medications may harm the retina by inhibiting mitochondrial energy metabolism, as they do to eliminate parasites.

Quality of hydroxychloroquine retinopathy screening at a Canadian teaching hospital.

PURPOSE: To assess the quality of hydroxychloroquine (HCQ)-induced retinopathy screening at a Canadian tertiary center, we concentrate on risk factor documentation within the electronic health record, in accordance with the 2016 AAO guidelines. METHODS: We performed a retrospective quality assessment study based on chart review of patients who underwent screening for HCQ-induced retinopathy at the Centre Hospitalier de l'Université de Montréal (CHUM) from 2016 to 2019. We evaluated four key risk factors for HCQ-induced retinopathy: daily dose, duration of use, renal disease, and tamoxifen use, using a three-tier grading system (ideal, adequate, inadequate) for documentation assessment. Pareto and root cause analyses were conducted to identify potential improvement solutions. RESULTS: Documentation quality varied in our study: daily dosage was 33% ideal, 31% appropriate, and 36% inappropriate. Duration of use documentation was 75% ideal, 2% adequate, and 24% inadequate. Renal disease documentation was only 6% ideal, with 62% adequate and 32% of charts lacking any past medical history. Among women's charts, tamoxifen use wasn't documented at all, with 65% adequately documenting medication lists. Pareto analysis indicated that improving renal disease and tamoxifen documentation could reduce 64% of non-ideal records, and enhancing daily dose documentation could decrease this by up to 90%. CONCLUSION: Accurate documentation of key risk factors is critical for HCQ-induced retinopathy screening, impacting both exam initiation and frequency. Our study identifies potential improvements in the screening process at the hospital, referring physician, and ophthalmologist levels. Implementing integrated pathways could enhance patient experience and screening effectiveness.

Poppers maculopathy missed in a patient with cataract highlights the importance of preoperative optical coherence tomography.

Poppers maculopathy is a complication of alkyl nitrate (poppers) inhalation. It presents with non-specific symptoms and variable signs, which can make it difficult to diagnose. We present a case of coexisting cataract and poppers maculopathy in a patient. He had vague visual symptoms that were attributed entirely to his cataract and he went on to have cataract surgery. Suboptimal postoperative visual acuity and normal clinical examination triggered further investigation with spectral-domain optical coherence tomography (SD-OCT), after which poppers maculopathy was diagnosed. We highlight the importance of performing OCT in the preoperative assessment of a cataract patient, especially where the cataract is mild and may not fully account for symptoms. The patient showed complete visual recovery on drug cessation despite ongoing maculopathy on OCT scans.

A case of successful treatment of a rare retinal disease presented by interferon-induced retinopathy.

OBJECTIVE: Aim: To showcase a rare retinal lesion and the results of contemporary diagnostic and treatment of interferon-induced retinopathy. PATIENTS AND METHODS: Materials and Methods: We describe a case of a 36-year-old patient with interferon-induced retinopathy, with hepatitis C, that received prolonged interferon treatment. Clinical signs, examination and combined laser and pharmacologic treatment were showcased in the study. RESULTS: Results: As a result of pharmacologic and laser treatment, the patient's visual acuity increased from 0.1 to 1.0 through the duration of 3 months after treatment. The patients` condition remained stable under dynamic observation. CONCLUSION: Conclusions: Because interferon-induced retinopathy is a rare occurrence in routine ophthalmologic practice, combined laser therapy can be used for treatment of preretinal hemorrhage, which leads to improvement of visual functions and stabilization of the retinal processes. This case is an addition to the few described cases of interferon-induced retinopathy.

Risk Factors for Hydroxychloroquine Retinopathy and Its Subtypes.

Importance: The major toxic effect of hydroxychloroquine is retinopathy. Thus, current guidelines recommend limiting the dose and screening annually for retinopathy among all long-term users, but individual patient factors may be associated with retinopathy risk. Objective: To identify risk factors beyond hydroxychloroquine dose and duration of use for hydroxychloroquine retinopathy. Design, Setting, and Participants: This cohort study of 4677 patients in the Kaiser Permanente Northern California integrated health network who initiated hydroxychloroquine, continued treatment, and underwent retinopathy screening after 5 years of use was conducted from July 1, 1997, to December 31, 2020, with up to 15 years of follow-up. Statistical analysis was performed in August 2023. Exposure: Candidate risk factors included age at hydroxychloroquine initiation, sex, race and ethnicity, indications, chronic kidney disease (CKD), liver disease, diabetes, tamoxifen use, and medications that interact with hydroxychloroquine metabolism. Hydroxychloroquine dose was assessed from pharmacy dispensing records. Main Outcome and Measures: Incident hydroxychloroquine retinopathy was adjudicated from masked review of guideline-recommended screening studies and classified as parafoveal or pericentral pattern. Multivariable Cox proportional hazards regression was used to assess potential risk factors for hydroxychloroquine retinopathy within 15 years of initiation. Results: Of 4677 long-term hydroxychloroquine users (mean [SD] age at initiation, 52.4 [14.1] years; 3877 women [82.9%]), 125 patients developed hydroxychloroquine retinopathy within 15 years (102 parafoveal, 23 pericentral). Older age at time of hydroxychloroquine initiation was associated with retinopathy risk, with adjusted hazard ratios (HRs) of 2.48 (95% CI, 1.28-4.78) for those aged 45 to 54 years, 3.82 (95% CI, 2.05-7.14) for those aged 55 to 64 years, and 5.68 (95% CI, 2.99-10.79) for those aged 65 years or older compared with those younger than 45 years. The risk of retinopathy was higher among females than males (HR, 3.83 [95% CI, 1.86-7.89]), among patients with CKD stage 3 or greater (HR, 1.95 [95% CI, 1.25-3.04]), and among individuals with tamoxifen use (HR, 3.43 [95% CI, 1.08-10.89]). The likelihood of pericentral retinopathy was higher among Asian patients (HR, 15.02 [95% CI, 4.82-46.87]) and Black patients (HR, 5.51 [95% CI, 1.22-24.97]) compared with non-Hispanic White patients. Conclusions and Relevance: This study suggests that increasing age, female sex, CKD stage 3 or greater, and tamoxifen use were associated with a higher risk of hydroxychloroquine retinopathy, whereas being younger than 45 years at hydroxychloroquine initiation and male sex were associated with a lower risk. Race and ethnicity were also associated with the pattern of retinopathy. These factors should be incorporated into hydroxychloroquine dosing decisions.

Presumed fluoxetine maculopathy.

To report a unique case of a patient who developed simultaneous bilateral maculopathy presumed from intake of fluoxetine. The optic coherence tomography (OCT) macular showed a subfoveal disruption in the outer retinal layer in both eyes (OU), higher in the left one (OS). Although reported cases of serotonin recapture inhibitors (SSRIs) Maculopathy so far have been caused by sertraline, fluoxetine shares the biological mechanism, and OCT findings and ocular symptoms are the same as published. We should be aware with ocular symptoms in patients that take fluoxetine.

Multimodal imaging in deferasirox-mediated retinopathy.

INTRODUCTION: Deferasirox is the only iron chelator available in oral formulation and a rare cause of pigmentary retinopathy. We report the first case of multimodal imaging in an adult with deferasirox retinopathy. METHODS: Case report and literature review, with search terms including deferasirox retinopathy and deferasirox toxicity. RESULTS: A 63-year-old man with end stage renal disease and transfusion-dependent anemia on deferasirox for one year presented with asymptomatic pigment epitheliopathy. Optical coherence tomography featured outer retinal and retinal pigment epithelial discontinuity corresponding to hypoautofluorescence on fundus autofluorescence and blocking on fluorescein angiography. Multifocal electroretinography revealed subtle reduction in all amplitudes. CONCLUSIONS: Retinal examinations should be considered for patients requiring chronic administration of deferasirox.

Exome sequencing and genome-wide association analyses unveils the genetic predisposition in hydroxychloroquine retinopathy.

OBJECTIVES: To unveil the candidate susceptibility genes in chloroquine/hydroxychloroquine (CQ/HCQ) retinopathy using whole exome sequencing (WES) and genome-wide association study (GWAS). METHODS: Patients with a diagnosis of CQ/HCQ retinopathy based on the comprehensive demographic and ocular examination were included. The peripheral blood was extracted for WES and GWAS analyses. The Chinese Han Southern database from 1000 genomes was used as control group to compare the affected percentage. Multivariate logistic regression analysis adjusted for age, HCQ dose, duration and renal disease were used to analyze the correlation between genetic variants and visual outcome. A poor vision outcome was defined as visual acuity <6/12. An abnormal anatomical outcome was defined as disruption of ellipsoid zone in the fovea. RESULTS: Twenty-nine patients with an average age of 60.9 ± 13.4 years, treatment duration of 12.1 ± 6.2 years, daily dose of 8.5 ± 4.1 mg/kg, and the cumulative dose of 1637.5 ± 772.5 g, were genotyped. Several candidate genes associated with CQ/HCQ retinopathy were found, including RP1L1, RPGR and RPE65, with a difference of affected percentage over 50% in mutation between the case and control groups. New foci in CCDC66: rs56616026 (OR = 63.43, p = 1.63 × 10-8) and rs56616023 (OR = 104.7, p = 5.02 × 10-10) were identified significantly associated with HCQ retinopathy. Multivariate analysis revealed increased genetic variants were significantly associated with poor functional (OR = 1.600, p = 0.004) and structural outcome (OR = 1.318, p = 0.043). CONCLUSIONS: Several candidate susceptibility genes including RP1L1, RPGR, RPE65 and CCDC66 were identified to be associated with CQ/HCQ retinopathy. In addition to disease susceptibility, patients with increased genetic variants are more vulnerable to poor visual outcomes.

Electroretinogram as a Screening Tool to Assess Vigabatrin-Induced Retinal Toxicity in Children With Infantile Spasms.

PURPOSE: To assess the utility of electroretinogram (ERG) as a screening tool for vigabatrin-induced retinal toxicity in children with infantile spasms. METHODS: This was an observational cohort study including children with infantile spasms receiving treatment with vigabatrin. A 30-Hz flicker potential ERG, using the RETeval system (LKC Technologies), was done at baseline before starting vigabatrin at 6 months and 1 year. The amplitudes were recorded. RESULTS: Eleven children were included in the study. The most common etiologic factor for infantile spasms was tuberous sclerosis (36.4%) followed by West syndrome (27.3%). The mean age of the children was 7.14 ± 2.9 months, with a range of 3 to 16 months. The mean difference in amplitude was 3.21 ± 2.45 and 5.72 ± 4.18 µV at 6 and 12 months follow-up, respectively (P < .001). Eight of the 11 children (72.7%) showed vigabatrin-induced retinal toxicity, and all 8 children were receiving vigabatrin for more than 6 months. CONCLUSIONS: ERG can be used for vigabatrin-induced retinal toxicity monitoring in children with infantile spasms. Vigabatrin-induced retinal toxicity is related to the duration of treatment rather than cumulative dosage. [J Pediatr Ophthalmol Strabismus. 2024;61(4):273-278.].

PEDF-derived peptide protects against Amyloid-ß toxicity in vitro and prevents retinal dysfunction in rats.

Amyloid-beta (Aß), a family of aggregation-prone and neurotoxic peptides, has been implicated in the pathophysiology of age-related macular degeneration (AMD). We have previously shown that oligomeric and fibrillar species of Aß42 exerted retinal toxicity in rats, but while the consequences of exposure to amyloid were related to intracellular effects, the mechanism of Aß42 internalization in the retina is not well characterized. In the brain, the 67 kDa laminin receptor (67LR) participates in Aß-related neuronal cell death. A short peptide derived from pigment epithelium-derived factor (PEDF), formerly designated PEDF-335, was found to mitigate experimental models of ischemic retinopathy via targeting of 67LR. In the present study, we hypothesized that 67LR mediates the uptake of pathogenic Aß42 assemblies in the retina, and that targeting of this receptor by PEDF-335 may limit the internalization of Aß, thereby ameliorating its retinotoxicity. To test this assumption ARPE-19 cells in culture were incubated with PEDF-335 before treatment with fibrillar or oligomeric structures of Aß42. Immunostaining confirmed that PEDF-335 treatment substantially prevented amyloid internalization into ARPE-19 cells and maintained their viability in the presence of toxic oligomeric and fibrillar Aß42 entities in vitro. FRET competition assay was performed and confirmed the binding of PEDF-335 to 67LR in RPE-like cells. Wild-type rats were treated with intravitreal PEDF-335 in the experimental eye 2 days prior to administration of retinotoxic Aß42 oligomers or fibrils to both eyes. Retinal function was assessed by electroretinography through 6 weeks post injection. The ERG responses in rats treated with oligomeric or fibrillar Aß42 assemblies were near-normal in eyes previously treated with intravitreal PEDF-335, whereas those measured in the control eyes treated with injection of the Aß42 assemblies alone showed pathologic attenuation of the retinal function through 6 weeks. The retinal presence of 67LR was determined ex vivo by immunostaining and western blotting. Retinal staining demonstrated the constitutional expression of 67LR mainly in the retinal nuclear layers. In the presence of Aß42, the levels of 67LR were increased, although its retinal distribution remained largely unaltered. In contrast, no apparent differences in the retinal expression level of 67LR were noted following exposure to PEDF-335 alone, and its pattern of localization in the retina remained similarly concentrated primarily in the inner and outer nuclear layers. In summary, we found that PEDF-335 confers protection against Aß42-mediated retinal toxicity, with significant effects noted in cells as well as in vivo in rats. The effects of PEDF-335 in the retina are potentially mediated via binding to 67LR and by at least partial inhibition of Aß42 internalization. These results suggest that PEDF-335 may merit further consideration in the development of targeted inhibition of amyloid-related toxicity in the retina. More broadly, our observations provide evidence on the importance of extracellular versus intracellular Aß42 in the retina and suggest concepts on the molecular mechanism of Aß retinal pathogenicity.

SCREENING PRACTICES AND LATE DIAGNOSIS OF HYDROXYCHLOROQUINE RETINOPATHY IN ASIAN PATIENTS.

PURPOSE: To investigate the associations between screening practices and late diagnosis in Asian patients with hydroxychloroquine retinopathy. METHODS: In total, 92 Korean patients with hydroxychloroquine retinopathy were included and separated into late diagnosis and earlier diagnosis groups according to the retinopathy stage at the time of diagnosis. Details of screening practices regarding timing and modalities for baseline and annual monitoring examinations were compared between the two groups. Adherence to the current American Academy of Ophthalmology guidelines was compared between the two groups. RESULTS: Timing of baseline and initial monitoring examinations was appropriate as per the Academy of Ophthalmology guidelines in only 5.3% of patients with late diagnosis. There were significant differences in the proportions of patients receiving initial monitoring at 5 years of use and those receiving annual monitoring between the late and earlier diagnosis groups ( P = 0.003 and <0.001, respectively). The duration from the start date of hydroxychloroquine therapy to the first monitoring examination was significantly prolonged in the late diagnosis group ( P < 0.001). Multivariate logistic regression revealed significant association of the time duration with the first monitoring examination ( P = 0.042) and age ( P = 0.028) with late diagnosis. CONCLUSION: Results of this study suggest that poor adherence to the Academy of Ophthalmology guideline, particularly delayed initial monitoring, may be associated with late diagnosis of hydroxychloroquine retinopathy.

Role of monocarboxylate transporters in AMPK-mediated protection against excitotoxic injury in the rat retina.

Activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK) pathway protects against N-methyl-D-aspartic acid (NMDA)-induced excitotoxic retinal injury. AMPK activation enhances fatty acid metabolism and ketone body synthesis. Ketone bodies are transported into neurons by monocarboxylate transporters (MCTs) and exert neuroprotective effects. In this study, we examined the distribution and expression levels of MCT1 and MCT2 in the retina and analyzed the effects of pharmacological inhibition of MCTs on the protective effects of metformin and 5-aminoimidazole-4-carboxamide (AICAR), activators of AMPK, against NMDA-induced retinal injury in rats. MCT1 was expressed in the blood vessels, processes of astrocytes and Müller cells, and inner segments of photoreceptors in the rat retina, whereas MCT2 was expressed in neuronal cells in the ganglion cell layer (GCL) and in astrocyte processes. The expression levels of MCT2, but not MCT1, decreased one day after intravitreal injection of NMDA (200 nmol). Intravitreal injection of NMDA decreased the number of cells in the GCL compared to the vehicle seven days after injection. Simultaneous injection of metformin (20 nmol) or AICAR (50 nmol) with NMDA attenuated NMDA-induced cell loss in the GCL, and these protective effects were attenuated by AR-C155858 (1 pmol), an inhibitor of MCTs. AR-C155858 alone had no significant effect on the retinal structure. These results suggest that AMPK-activating compounds protect against NMDA-induced excitotoxic retinal injury via mechanisms involving MCTs in rats. NMDA-induced neurotoxicity may be associated with retinal neurodegenerative changes in glaucoma and diabetic retinopathy. Therefore, AMPK-activating compounds may be effective in managing these retinal diseases.

Novel optical coherence tomography findings in a patient with methanol toxicity: a case report.

We report a case of acute methanol toxicity with unique optical coherence tomography findings. A 56-year-old man was referred to our ophthalmology clinic with a history of handmade vodka consumption and vision loss. On ophthalmologic examination, his vision was 20/100 in his right eye and 20/200 in his left eye. Bilateral mild optic disk hyperemia was detected on fundus examination. Because of the severity of systemic symptoms in such cases, it is very difficult to include optical coherence tomography in the ophthalmologic examination. However, we managed to perform optical coherence tomography and recorded shallow subretinal fluid and a prominent middle limiting membrane sign as acute retinal structural changes in the patient. The patient was treated with hemodialysis, intravenous ethanol, and sodium bicarbonate. On the fourth day of treatment, visual acuity improved to 20/20 in both eyes. In addition, the prominent middle limiting membrane sign and subretinal fluid disappeared. In this unusual case, retinal pigment epithelium damage and retinal ischemia may have contributed to the prominent middle limiting membrane and subretinal fluid, which are novel optical coherence tomography findings of methanol toxicity.

Identification of new risk factors for hydroxychloroquine and chloroquine retinopathy in systemic lupus erythematosus patients.

BACKGROUND: Long-term hydroxychloroquine (HCQ) or chloroquine (CQ) intake causes retinal toxicity in 0.3-8 % of patients with rheumatic diseases. Numerous risk factors have been described, eg, daily dose by weight, treatment duration, chronic kidney disease, concurrent tamoxifen therapy and pre-existing retinal or macular disease. However, those factors cannot explain the entire risk of developing antimalarial retinopathy. OBJECTIVE: This study was undertaken to identify new risk factors associated with HCQ or CQ retinopathy (QRNP) in systemic lupus erythematosus (SLE) patients. METHODS: This case-control (1:2) study compared SLE patients with QRNP (cases) to those without (controls). Controls were matched for sex and known QRNP risk factors: HCQ and/or CQ treatment duration (±1 year) and age (±5 year) at SLE diagnosis. RESULTS: Forty-eight cases were compared to 96 SLE controls. Multivariable logistic-regression analysis retained the following as independent determinants significantly associated with QRNP: concomitant selective serotonin-reuptake inhibitor (SSRI) or serotonin- and norepinephrine-reuptake inhibitor (SNRI) intake (OR [95 % confidence interval] 6.6 [1.2 to 40.9]; p < 0.01); antiphospholipid syndrome (OR=8.9 [2.2 to 41.4] p < 0.01); blood hydroxychloroquine/desethylchloroquine concentration ([HCQ]/[DCQ]) ratio <7.2 (OR 8.4 [2.7 to 30.8]; p < 0.01) or skin phototype ≥4 (OR 5.5 [1.4 to 26.5]; p = 0.02), but not daily HCQ dose, blood [HCQ] or body mass index. CONCLUSION: The results of this case-control study identified blood [HCQ]/[DCQ] ratio, concurrent SSRI/SNRI therapy, skin phototype ≥4 and antiphospholipid syndrome as new risk factors for QRNP.

Crystalline Retinopathy Following Intravitreal Clindamycin.

This case report describes a 74-year-old woman who developed a crystalline retinopathy following intravitreal injection of clindamycin. The patient presented with ocular toxoplasmosis in the left eye but was allergic to sulfa medications, so she was treated with intravitreal clindamycin. Subsequently, fine refractile yellow-white crystals were observed on examination of the left macula. Optical coherence tomography localized the crystals to the posterior hyaloid. Intravitreal clindamycin should be considered in the differential diagnosis of crystalline retinopathy. [Ophthalmic Surg Lasers Imaging Retina 2024;55:168-170.].

Demographic and clinical characteristics associated with screening practices for hydroxychloroquine retinopathy.

In this nationwide population-based cohort study, we investigated the demographic and clinical characteristics associated with hydroxychloroquine retinopathy screening using the National Health Insurance Review and Assessment database in South Korea. This study included a total of 32,732 at-risk patients, identified based on having been prescribed hydroxychloroquine for at least 6 months, and 15,477 long-term (> 5 years) users between January 2010 and December 2020. Participants were categorized based on the performance of baseline examinations (within 1 year of hydroxychloroquine use) and monitoring examinations (after 5 years of hydroxychloroquine use). Demographic and clinical factors, including hospitals and medical specialties prescribing hydroxychloroquine, indications for hydroxychloroquine use, and prescription details, were compared between groups. Significant differences were found in sex, residence, departments and hospitals (primary vs. referral centers) where hydroxychloroquine was prescribed, diagnosis for hydroxychloroquine therapy, and mean daily dose between patients who did and did not undergo baseline or monitoring examinations (all P < 0.01). Patients who received hydroxychloroquine prescriptions from referral hospitals were more likely to undergo baseline and monitoring examinations compared to those from primary clinics (both P < 0.001). Additionally, patients who received hydroxychloroquine prescriptions from the rheumatology department and had systemic lupus erythematosus were more likely to undergo baseline and monitoring examinations compared to other patients (all P < 0.001). There were notable differences in the number of modalities used for retinopathy screening between primary and referral centers (P < 0.001). Our findings suggest that several clinical factors related to hydroxychloroquine prescription and screening centers are associated with retinopathy screening practices.