Leber Hereditary Optic Neuropathy in Southwestern Ontario: A Growing List of Mutations.

BACKGROUND: Leber hereditary optic neuropathy (LHON) is a rare but bilaterally blinding disease. Three characteristic disease-causing point mutations, and other less common mutations, are most often found on the mitochondrially encoded genes of NADH-ubiquinone oxidoreductase core subunits (MT-ND). The purpose of this study is to provide an overview of LHON mutations in Southwestern Ontario and to describe the associated demographic and clinical characteristics. METHODS: A retrospective genetic and clinical chart review was performed from January 2015 to 2020. Patients were identified within a mitochondrial mutation database and included if a mutation was detected on the MT-ND1, -ND4, or -ND6 genes. A clinical chart review was done on all available patients. RESULTS: Forty-five of 63 patients identified had classic disease-causing mutations (6.7% m.3460G>A, 44.4% m.11778G>A, and 48.9% m.14484T>C). Several of the remaining 18 patients had rare mutations previously documented in association with LHON. Of the 14 patients with clinical charts accessible for review, 12 had symptomatic disease, and all but one had bilateral optic neuropathies. Nine patients had classic LHON mutations and 3 had possible novel mutations; 7 were males; 9 had final visual acuity ≤ 20/200 in at least one eye; and 6 of those had ≤20/400 in both eyes. CONCLUSIONS: This study adds to the literature on LHON in Canada, and specifically Southwestern Ontario. The demographic and clinical data regarding LHON in this geographic location, as well as possible novel disease-causing mutations, provide important information to aid clinicians in recognizing cases of LHON that may otherwise be disregarded.

Spastic Paraplegia Type 7-Associated Optic Neuropathy: A Case Series.

BACKGROUND: Hereditary optic neuropathies comprise a group of clinically and genetically heterogeneous disorders. Optic neuropathy has been previously reported in families with spastic paraplegia type 7 (SPG7) gene mutations. However, the typical time course and clinical presentation of SPG7-associated optic neuropathy is poorly understood. We report a series of 5 patients harboring pathogenic SPG7 mutations who originally presented to a neuro-ophthalmology clinic with symptoms of optic neuropathy. METHODS: Retrospective case series of 5 patients with pathogenic SPG7 mutations and optic atrophy from 3 neuro-ophthalmology clinics. Demographic, clinical, diagnostic, and treatment data were collected and reported by the clinician authors. RESULTS: Five patients ranging in age from 8 to 48 years were evaluated in the neuro-ophthalmology clinic. Although there were variable clinical presentations for each subject, all noted progressive vision loss, typically bilateral, and several also had previous diagnoses of peripheral neuropathy (e.g., Guillain-Barré Syndrome). Patients underwent neuro-ophthalmic examinations and testing with visual fields and optic coherence tomography of the retinal nerve fiber layer. Genetic testing revealed pathogenic variants in the SPG7 gene. CONCLUSIONS: Five patients presented to the neuro-ophthalmology clinic with progressive vision loss and were diagnosed with optic atrophy. Although each patient harbored an SPG7 mutation, this cohort was phenotypically and genotypically heterogeneous. Three patients carried the Ala510Val variant. The patients demonstrated varying degrees of visual acuity and visual field loss, although evaluations were completed during different stages of disease progression. Four patients had a previous diagnosis of peripheral neuropathy. This raises the prospect that a single pathogenic variant of SPG7 may be associated with peripheral neuropathy in addition to optic neuropathy. These results support the consideration of SPG7 testing in patients with high suspicion for genetic optic neuropathy, as manifested by symmetric papillomacular bundle damage without clear etiology on initial workup. Applied judiciously, genetic testing, including for SPG7, may help clarify the cause of unexplained progressive optic neuropathies.

Extraocular Muscle Enlargement in Acromegaly.

BACKGROUND: To determine whether acromegaly is associated with increased extraocular muscle (EOM) size at time of presentation. METHODS: Patients with a new diagnosis of acromegaly in a single tertiary care clinic with a CT scan that adequately delineated the EOMs were included. Control subjects were age- and sex-matched patients with a new diagnosis of nonfunctioning pituitary adenoma. Retrospective chart review was performed to extract baseline clinical and laboratory parameters including growth hormone, insulin-like growth factor 1, thyroid stimulating hormone, free T3, and free T4. A single neuroradiologist analyzed all CT scans and measured the maximum diameter and cross-sectional area of the superior rectus, inferior rectus, medial rectus, and lateral rectus in both eyes of all patients. RESULTS: We evaluated 17 patients with acromegaly and 18 control subjects. Mean maximum diameter of the superior, inferior, medial, and lateral recti were 4.80 mm (SD = 0.81), 4.67 mm (SD = 0.54), 4.86 mm (SD = 0.77), and 4.53 mm (SD = 0.70) respectively, in the acromegaly group. In the control group, they were 3.62 mm (SD = 0.58),3.71 mm (SD = 0.46), 3.66 mm (SD = 0.32), and 3.21 mm (SD = 0.44), respectively. The maximum diameter and cross-sectional area of all 4 EOMs measured in the acromegaly group were significantly larger ( P < 0.001) compared with the control group. CONCLUSIONS: Patients with acromegaly present with significantly enlarged EOMs compared with control subjects with nonfunctioning pituitary adenomas.

Validation and clinical performance of a combined nuclear-mitochondrial next-generation sequencing and copy number variant analysis panel in a Canadian population.

Diagnosing mitochondrial disorders is a challenge due to the heterogeneous clinical presentation and large number of associated genes. A custom next generation sequencing (NGS) panel was developed incorporating the full mitochondrial genome (mtDNA) plus 19 nuclear genes involved in structural mitochondrial defects and mtDNA maintenance. This assay is capable of simultaneously detecting small gene sequence variations and larger copy number variants (CNVs) in both the nuclear and mitochondrial components along with heteroplasmy detection down to 5%. We describe technical validations of this panel and its implementation for clinical testing in a Canadian reference laboratory, and report its clinical performance in the initial 950 patients tested. Using this assay, we demonstrate a diagnostic yield of 18.1% of patients with known pathogenic variants. In addition to the common 5 kb mtDNA deletion, we describe significant contribution of pathogenic CNVs in both the mitochondrial genome and nuclear genes in this patient population.

Visual Outcomes in Surgically Treated Intracranial Meningiomas.

BACKGROUND: Intracranial meningiomas that arise from the medial sphenoid ridge, anterior clinoid process, tuberculum sellae, or planum sphenoidale often impair vision by compressing the optic nerves and optic chiasm. Although many studies have reported visual outcome following surgery for these tumors, documentation has often been incomplete and not validated by patient self-report. METHODS: Retrospective study of 40 patients drawn from a single, academic, medical center. We used a unique method of assessing visual outcome based on whether the change in visual function affected the preoperatively better-sighted or worse-sighted eye in the belief that this method would correlate with effects on activities of daily living (ADL). To elicit patient self-reports of those effects, we conducted telephone interviews of 25 patients with a standard questionnaire. We also assessed putative ophthalmic, imaging, and surgical predictors of visual outcome. RESULTS: Visual improvement occurred in 61% of patients with preoperative monocular visual dysfunction, but only 22% of patients reported improvement in their ability to conduct ADL, and 17% lost vision. Visual outcomes were better in patients with preoperative binocular visual dysfunction, where visual improvement occurred in 73% and no patient lost vision in the preoperatively better-sighted eye. However, only 27% of patients with preoperative binocular visual dysfunction reported improvement in their ability to conduct ADL. Long duration of vision impairment, presence of optic disc pallor, large tumor size, and imaging-based preoperative optic canal involvement did not preclude a favorable visual outcome. Aggressive surgical reduction in displacement of the optic nerves was not necessary to obtain a favorable visual outcome and sometimes led to an unfavorable visual outcome. CONCLUSIONS: In this study, surgery often improved vision, especially in patients with preoperative binocular visual dysfunction. But patients indicated that the effect on their ability to perform ADL was more modest. Moreover, 17% of patients with preoperative monocular visual dysfunction lost vision in the only affected eye, often to a considerable degree. In those patients, surgery would be justified primarily to relieve the concern of having a large brain tumor and to prevent tumor growth. Preoperative ophthalmic and imaging features poorly predicted visual outcomes. Favorable visual outcomes occurred without aggressive surgical debulking of the tumors.

Paraneoplastic Ophthalmoplegia as the Presenting Sign of Paediatric Glioblastoma Multiforme: A Case Report.

Glioblastoma multiforme (GBM) is an aggressive glioma that is infrequently diagnosed in the paediatric population. GBM and other primary brain tumours have rarely been associated with paraneoplastic syndromes. We report an unusual case of an 8-year-old boy presenting with an inability to abduct his left eye and almost complete ophthalmoplegia of his right eye, prior to any radiological evidence of GBM. This is the first documented case of paediatric GBM presenting with bilateral asymmetric ophthalmoplegia.

Optic Nerve Atrophy in N-methyl-D-aspartate (NMDA) Encephalitis.

N-methyl-D-aspartate receptor (NMDA) encephalitis is a recently described autoimmune disease that typically presents with prodromal symptoms including upper respiratory tract infection, headache, fever, nausea, vomiting and diarrhea. Psychiatric symptoms follow within weeks, including anxiety, insomnia, mania, paranoia and grandiose delusions. The diagnosis is confirmed by the detection of NMDA antibodies in the serum or cerebrospinal fluid (CSF).1 Tumours, especially teratomas, are frequently associated with NMDA encephalitis; however, only 5% of male patients older than 18 years have been found to have an underlying tumour. Optic neuropathy associated with NMDA encephalitis is being increasingly recognised in the literature2-6 and was reviewed most recently by Mugavin et al.2 in 2017. In this report, we present a case of bilateral optic neuropathy in a young man diagnosed with NMDA receptor encephalitis.

Putaminal Diffusion Restriction in a Case of Methanol Toxicity with Clinical Recovery.

A 32-year-old male presented to the emergency department for confusion, dyspnea, and a "white out" of his central vision over the preceding 24 hours. The patient had recently consumed a bottle of alcohol purchased overseas. Bloodwork revealed a severe metabolic acidosis (pH 6.90) and a critically high methanol level of 28.9 mmol/l. Shortly after presentation, the patient went into respiratory failure and became comatose. He was intubated and admitted to the ICU.

Multirater Validation of Peripapillary Hyperreflective Ovoid Mass-like Structures (PHOMS).

Peripapillary hyperreflective ovoid mass-like structures (PHOMS) are a new retinal optical coherence tomography (OCT) finding. The Optic Disc Drusen Studies Consortium had made recommendations to distinguish PHOMS from true optic disc drusen (ODD) in 2018. While publications on PHOMS have increased since then, the accuracy of the definition of PHOMS and reliability of detection is unknown. In this multi-rater study, we demonstrate that the 2018 definition of PHOMS resulted in a poor multi-rater kappa of 0.356. We performed a Delphi consensus process to develop a consistent and refined definition of PHOMS with clear principles around the nature of PHOMS and how they differ from normal anatomy. Fifty explanatory teaching slides, provided as supplementary material, allowed our expert group of raters to achieve a good level of agreement (kappa 0.701, 50 OCT scans, 21 raters). We recommend adopting the refined definition for PHOMS.

The Optic Disc Drusen Studies Consortium Recommendations for Diagnosis of Optic Disc Drusen Using Optical Coherence Tomography.

BACKGROUND: Making an accurate diagnosis of optic disc drusen (ODD) is important as part of the work-up for possible life-threatening optic disc edema. It also is important to follow the slowly progressive visual field defects many patients with ODD experience. The introduction of enhanced depth imaging optical coherence tomography (EDI-OCT) has improved the visualization of more deeply buried ODD. There is, however, no consensus regarding the diagnosis of ODD using OCT. The purpose of this study was to develop a consensus recommendation for diagnosing ODD using OCT. METHODS: The members of the Optic Disc Drusen Studies (ODDS) Consortium are either fellowship trained neuro-ophthalmologists with an interest in ODD, or researchers with an interest in ODD. Four standardization steps were performed by the consortium members with a focus on both image acquisition and diagnosis of ODD. RESULTS: Based on prior knowledge and experiences from the standardization steps, the ODDS Consortium reached a consensus regarding OCT acquisition and diagnosis of ODD. The recommendations from the ODDS Consortium include scanning protocol, data selection, data analysis, and nomenclature. CONCLUSIONS: The ODDS Consortium recommendations are important in the process of establishing a reliable and consistent diagnosis of ODD using OCT for both clinicians and researchers.

Accuracy and Reliability of a Handheld, Nonmydriatic Fundus Camera for the Remote Detection of Optic Disc Edema.

BACKGROUND: Optic disc edema can be an important indicator of serious neurological disease, but is poorly detected using the direct ophthalmoscope. Portable fundus photography may overcome this difficulty. INTRODUCTION: The purpose of this study was to determine the sensitivity and specificity of a handheld, nonmydriatic fundus camera for the detection of optic disc edema. MATERIALS AND METHODS: Retrospective review of nonmydriatic optic disc photographs taken with a portable fundus camera (Pictor Plus; Volk Optical, Mentor, OH) from the University of Michigan Neuro-Ophthalmology Clinics. We included 103 consecutive eyes with optic disc edema and 103 consecutive eyes without optic disc edema of 109 patients. Four masked neuro-ophthalmologists graded a single photograph of each optic disc presented in randomized order and documented the presence of optic disc edema. Sensitivity and specificity of graders' photographic interpretation was compared with clinical examinations. Reliability of assessments within and between graders was determined using kappa statistics. RESULTS: The sensitivity and specificity for detection of optic disc edema were 71.8-92.2% and 81.6-95.2%, respectively. Photos were found to be ungradable in 0-8.3% of cases. The intergrader reliabilities ranged from 0.60 [95% confidence interval (CI): 0.52-0.67] to 0.72 (95% CI: 0.66-0.77). Intragrader reliability ranged from 0.76 (95% CI: 0.63-0.92) to 0.82 (95% CI: 0.69-0.95). DISCUSSION: Photographs taken with portable, nonmydriatic technology met threshold sensitivity and specificity for remote screening for optic disc edema when performed by most, but not all graders. Reliability between graders was moderate-strong and strong within individual providers. CONCLUSIONS: Portable photography holds promise for use in remote screening of optic disc edema.

Multiple Cranial Nerve Palsies in Giant Cell Arteritis.

Giant cell arteritis (GCA) is a systemic vasculitis of medium and large arteries often with ophthalmic involvement, including ischemic optic neuropathy, retinal artery occlusion, and ocular motor cranial nerve palsies. This last complication occurs in 2%-15% of patients, but typically involves only 1 cranial nerve. We present 2 patients with biopsy-proven GCA associated with multiple cranial nerve palsies.

Positive Apraclonidine Test in Horner Syndrome Caused by Thalamic Hemorrhage.

Reversal of anisocoria following instillation of apraclonidine 0.5% has been reported in Horner syndrome caused by lesions of the central and peripheral nervous system. The shortest documented latency between symptom onset and a positive apraclonidine test is 36 hours, occurring in a patient with a pontomedullary infarct. We present the case of a 69-year-old man with Horner syndrome due to thalamic hemorrhage in whom apraclonidine testing demonstrated reversal of anisocoria 4 days after symptom onset. This is the first reported case of a positive apraclonidine test in a Horner syndrome caused by a lesion at this site. It suggests that apraclonidine testing is useful in confirming the diagnosis within days of onset even in a lesion located at the most proximal portion of the oculosympathetic pathway.

Vision Loss Caused by Retinal and Lateral Geniculate Nucleus Infarction in H1N1 Influenza.

A 13-year-old girl developed encephalopathy and severe bilateral vision loss to the level of light perception within 24 hours of having fever and myalgias heralding H1N1 influenza A. Ophthalmoscopy demonstrated findings of confluent ischemic retinopathy. Brain MRI disclosed lateral geniculate body signal abnormalities indicative of hemorrhagic infarction. Despite aggressive treatment with intravenous corticosteroids, intravenous immunoglobulin, and plasmapheresis, vision did not substantially improve. This case demonstrates that H1N1 can cause simultaneous retinal and lateral geniculate body infarctions, a combination of findings not previously described in any condition. We postulate an immunologic response to the virus marked by occlusive damage to arteriolar endothelium.

Congenital trochlear-oculomotor synkinesis.

Synkinesis of the extraocular muscles forms a subset of congenital ocular motility abnormalities termed congenital cranial dysinnervation disorders. Synkinesis most frequently involves the abducens or oculomotor nerves and rarely the trochlear nerve. Only 3 such patients have been described in the literature. We report an isolated case of trochlear-oculomotor synkinesis in a healthy 6-year-old boy and discuss the proposed pathophysiology of this disorder.

Low-grade intraductal carcinoma of the lacrimal gland.

Intraductal carcinoma has been described in the salivary glands as a relatively benign tumour with low-grade histopathologic features. To our knowledge, this tumour has not previously been reported in the lacrimal gland. We report the first case of low-grade intraductal carcinoma occurring in the lacrimal gland. This tumour was discovered incidentally on neuro-imaging in an asymptomatic 65-year-old patient. Incisional biopsy revealed uniform, polygonal cells with eosinophilic cytoplasm and minimal nuclear atypia, arranged in solid, cribiform and micropapillary nests. The patient underwent complete surgical excision with no evidence of recurrence at 8 months of follow-up.

Association of pre-residency publications with research productivity in residency, fellowship, and academic career choice among Canadian ophthalmologists.

OBJECTIVE: This study aimed to assess whether the research output of medical students who matched into a Canadian ophthalmology residency program influences their subsequent research productivity during residency, decision to pursue a fellowship, or engagement in academic practice. DESIGN: Retrospective database review. PARTICIPANTS: A total of 369 trainees commencing ophthalmology residency from 2004 to 2015 at 15 residency programs. METHODS: Each trainee's publication record was queried in Scopus before and after the date they started residency. Multiple public sources were searched to identify fellowship placement and the type of subsequent practice (i.e., academic or community). Predictors of research productivity during residency, fellowship, and practice setting were assessed using multivariable regression analyses. RESULTS: Trainees with pre-residency publications (n = 187) demonstrated significantly higher research productivity during residency than those without pre-residency publications (n = 182), with a mean of 5.17 ± 5.97 versus 1.60 ± 2.38 publications on any topic (p < 0.001). Pre-residency research output was a predictor of research productivity during residency (relative risk = 1.17; 95% CI, 1.09-1.27; p < 0.001), pursuing fellowship (odds ratio, 2.9; 95% CI, 1.74-4.83), and an academic career (odds ratio = 1.85; 95% CI, 1.07-3.2). CONCLUSION: Pre-residency research output is a significant predictor of research productivity during residency and subsequent career choices, suggesting that pre-residency publishing reflects a propensity toward an academic trajectory. Residency publication count moderates this association, underscoring the role of the residency program environment in fostering research productivity. Addressing barriers such as mentorship, funding, and curriculum may be key to incentivizing trainees to pursue academic medicine.