Sensitivity of Magnetic Resonance Imaging of the Medial Longitudinal Fasciculus in Internuclear Ophthalmoplegia.

BACKGROUND: Internuclear ophthalmoplegia (INO) is a result of insult to the medial longitudinal fasciculus (MLF). Clinicoradiological correlation in patients with INO has been reported to be poor; however, prior studies have used low resolution MRI imaging techniques and included patients with subclinical INO. We aimed to determine the sensitivity of modern MRI interpreted by a specialist neuroradiologist to detect clinically evident INO. METHODS: A retrospective chart review of patients in 2 tertiary University-affiliated neuro-ophthalmology practices with the diagnosis of INO. MRI scans of all patients were reviewed and interpreted by a fellowship-trained neuroradiologist for the presence of lesion in MLF and concordance with the original imaging report. RESULTS: Forty-five patients were included in the study: 33 with demyelinating disease, 11 with stroke, and 1 with intracranial mass. A visible MLF lesion was present in 25/33 demyelinating cases and 7/11 ischemic cases. Lesions in 2 cases in each group were identified only after review by a fellowship-trained neuroradiologist. In demyelinating INO, patients with a visible MLF lesion were more likely to show other brainstem (72%) and supratentorial (51%) white matter lesions. CONCLUSIONS: In 25% of patients with demyelinating INO and 33% of patients with ischemic INO, no visible lesion was identified on current high-quality MRI imaging. Review of imaging by a neuroradiologist increased the possibility of lesion been identified.

Anti-Ma2 Antibody-Mediated Paraneoplastic Cerebellar Degeneration and Myeloneuropathy Secondary to Lymphoma.

ABSTRACT: A 61-year-old woman with a history of untreated low-grade B-cell lymphoma presented with blurry vision, unsteadiness, and worsening pain on touching skin of the upper trunk was enrolled. Blurry vision was attributed to oscillopsia from downbeat nystagmus, which later evolved into macrosaccadic oscillations. MRI brain and spine showed mild, longitudinally extensive T2 hyperintensity in the central gray matter of the spinal cord extending from the medulla to T11 level. Serum paraneoplastic panel was negative; however, she had very high titers of anti-Ma2 antibodies in cerebrospinal fluid. The diagnosis of paraneoplastic neurological syndrome was made. Empiric treatment with high dose of intravenous steroids followed by intravenous immunoglobulin infusions did not improve her symptoms. An extensive search for an underlying tumor commenced and was initially unrevealing. However, two-month follow-up positron emission tomography scan showed increased uptake in a right pulmonary nodule, which when biopsied confirmed diagnosis of extranodal marginal zone lymphoma. The final diagnosis was anti-Ma2 antibody-mediated paraneoplastic cerebellar degeneration and myeloneuropathy secondary to lymphoma.

The Leading Causes of Optic Disc Edema Seen in Tertiary Care, Academic Neuro-Ophthalmology Clinics.

BACKGROUND: Optic disc edema (ODE) is one of the most common reasons for referral to a neuro-ophthalmologist. There are various causes that require vastly different workup. Thus, differentiating among each cause is important. Our goal was to determine the causes of ODE and various clinical characteristics of consecutive patients with ODE presenting to neuro-ophthalmology clinics. METHODS: A retrospective review of consecutive patients with ODE over a period of 5 years were included. Fundus photographs were routinely obtained as part of clinical care. Clinical data including retinal nerve fiber layer thickness, best-corrected visual acuity, and visual field mean deviation were retrieved, and patients were grouped by etiology. RESULTS: A total of 654 patients (n = 462 or 70.6% women and 192 or 29.4% men) with ODE were included with a mean age of 41.2 ± 17.9 years. Female patients were significantly younger than male patients (mean age female participants: 38.7 years, male participants: 47.6; P < 0.001). The top 5 most common causes of ODE in our clinics were idiopathic intracranial hypertension (IIH; 351/654 or 53.7%), nonarteritic anterior ischemic optic neuropathy (NAION; 116/654 or 17.4%), non-IIH papilledema (71/654 or 10.9%), optic neuritis (ON; 46/654 or 7.0%), and uveitis (17/654 or 2.6%). When considering female-only patients, the top 3 causes of ODE were IIH, non-IIH papilledema, and NAION. Among male-only patients, the top 3 causes were NAION, IIH, and non-IIH. Among the top 5 causes of ODE, visual acuity was the worst at presentation in the ON group and the best in the patients with IIH. The Humphrey mean deviation was the worst in ON/NAION groups and best in IIH group. The ODE was most severe in patients with non-IIH papilledema and least severe in ON group. Non-IIH patients with papilledema were not significantly different in visual acuity and visual field parameters at presentation compared with patients with IIH papilledema. Patients with papilledema (both IIH and non-IIH etiologies) had significantly better visual function at presentation compared with other top causes of disc edema (P < 0.001). CONCLUSIONS: The most common cause of ODE seen in neuro-ophthalmology clinics was IIH, and these patients were more likely to present with preserved visual function. The higher prevalence of IIH was likely why most patients with ODE were women. Visual function at presentation was not able to differentiate the specific cause of papilledema; however, it was an important differentiating factor for all papilledema cases compared with all other causes of ODE including ON and NAION.

Visual and Pharmacotherapy Outcomes After Transverse Sinus Stenting for Idiopathic Intracranial Hypertension.

BACKGROUND: Transverse sinus stenting (TSS) is an increasingly common treatment for patients with idiopathic intracranial hypertension (IIH). However, detailed neuro-ophthalmic evidence on visual and pharmacotherapy outcomes after TSS is scarce and heterogeneous. This study aimed to describe the visual outcomes of patients undergoing TSS for IIH and to ascertain the proportion of patients who could be weaned off intracranial pressure (ICP)-lowering medication postoperatively. METHODS: A retrospective chart review of all patients with IIH from 2 tertiary academic neuro-ophthalmology practices who underwent TSS between 2016 and 2022 was performed. Indications for stenting included failure of pharmacotherapy, intolerance of pharmacotherapy, and acute vision loss from severe papilledema. Data on demographics, symptoms, visual function, pharmacotherapy, and TSS were collected. The paired Wilcoxon rank sum test was used to compare changes in visual acuity (VA) and visual field mean deviation (VFMD) between the baseline and most recent visits. RESULTS: Of the 435 patients with IIH, 15 (13 women) met inclusion criteria. After TSS, ICP-lowering pharmacotherapy was discontinued in 10 patients and decreased in 4; 1 patient was not on ICP-lowering medication before TSS. All patients experienced resolution or improvement of symptoms (10 resolution, 4 improved, 1 asymptomatic before TSS) and papilledema (11 resolution, 4 improved) after stenting. Papilledema resolution was confirmed with optical coherence tomography-measured peripapillary nerve fiber layer thickness (median decrease 147 µm, interquartile range 41.8-242.8 µm, P < 0.001). Change in VA between the baseline and most recent visit was not significant, but VFMD improved significantly after stenting (median increase 3.0, IQR 2.0-4.2, P < 0.001). No patient developed transverse sinus restenosis nor in-stent thrombosis postoperatively across a median venogram follow-up of 20.8 (11.3-49.8) weeks. In addition, no patient required subsequent surgical intervention for IIH. CONCLUSIONS: In this cohort of patients with IIH and fulminant presentation, medication resistance, or medication intolerance, TSS was an effective and safe treatment modality. Most patients were able to stop ICP-lowering medications while demonstrating striking improvement in symptomatology and visual function.

Assessment of Reversibility of Transverse Venous Sinus Stenosis in Patients With Papilledema.

BACKGROUND: Bilateral transverse venous sinus stenosis (TVSS) or stenosis of a dominant venous sinus has been found to be very sensitive radiological findings in patients with intracranial hypertension (IH), yet there is still an ongoing debate whether they constitute reversible or permanent phenomena. Thus, the purpose of this study was to investigate the reversibility of TVSS in patients with IH, including conservatively treated patients with signs of IH as defined by the presence of papilledema. METHODS: This was a retrospective chart review of all patients diagnosed with IH between 2016 and 2022, assessed from 2 tertiary university-affiliated neuro-ophthalmology practices. Inclusion criteria were the presence of papilledema, as quantified by optical coherence tomography, and bilateral TVSS, which is considered typical of IH on neuroimaging. During follow-up, included patients must have had confirmation of papilledema resolution as well as subsequent neuroimaging after conservative treatment or cerebrospinal fluid flow diversion. Patients with dural sinus vein thrombosis or intrinsic stenosis from sinus trabeculations or significant arachnoid granulations were excluded from the study. Either CT venography or MRI/MR venography was reviewed by a fellowship-trained neuroradiologist, and the degree of stenosis was scored through the combined conduit score (CCS), as described by Farb et al. The primary outcome was to assess TVSS changes after resolution or improvement of papilledema. RESULTS: From 435 patients, we identified a subset of 10 who satisfied all inclusion criteria. Our cohort comprised entirely women with a median age of 29.5 years and a median BMI of 32.5 kg/m2. Treatment consisted of acetazolamide in 7 patients, of which 1 had additional topiramate and 2 underwent cerebrospinal fluid flow diversion. Furthermore, 6 patients demonstrated significant weight loss during follow-up. For the primary outcome, 5 of 10 patients exhibited no appreciable TVSS change, and 5 patients demonstrated significant improvement in TVSS, of which 4 received conservative treatment only. Papilledema resolution or improvement was statistically significantly associated with increasing average CCS, TVSS diameter, and grade. CONCLUSIONS: We were able to demonstrate that TVSS can be both irreversible and reversible in patients with resolved papilledema. The finding of TVSS reversibility from conservative treatment alone is novel and has important implications to optimize patient care. Future studies should work to identify factors associated with irreversible TVSS for subsequent targeted intervention and prevention.

Utility of ChatGPT for Automated Creation of Patient Education Handouts: An Application in Neuro-Ophthalmology.

BACKGROUND: Patient education in ophthalmology poses a challenge for physicians because of time and resource limitations. ChatGPT (OpenAI, San Francisco) may assist with automating production of patient handouts on common neuro-ophthalmic diseases. METHODS: We queried ChatGPT-3.5 to generate 51 patient education handouts across 17 conditions. We devised the "Quality of Generated Language Outputs for Patients" (QGLOP) tool to assess handouts on the domains of accuracy/comprehensiveness, bias, currency, and tone, each scored out of 4 for a total of 16. A fellowship-trained neuro-ophthalmologist scored each passage. Handout readability was assessed using the Simple Measure of Gobbledygook (SMOG), which estimates years of education required to understand a text. RESULTS: The QGLOP scores for accuracy, bias, currency, and tone were found to be 2.43, 3, 3.43, and 3.02 respectively. The mean QGLOP score was 11.9 [95% CI 8.98, 14.8] out of 16 points, indicating a performance of 74.4% [95% CI 56.1%, 92.5%]. The mean SMOG across responses as 10.9 [95% CI 9.36, 12.4] years of education. CONCLUSIONS: The mean QGLOP score suggests that a fellowship-trained ophthalmologist may have at-least a moderate level of satisfaction with the write-up quality conferred by ChatGPT. This still requires a final review and editing before dissemination. Comparatively, the rarer 5% of responses collectively on either extreme would require very mild or extensive revision. Also, the mean SMOG score exceeded the accepted upper limits of grade 8 reading level for health-related patient handouts. In its current iteration, ChatGPT should be used as an efficiency tool to generate an initial draft for the neuro-ophthalmologist, who may then refine the accuracy and readability for a lay readership.

Inappropriate Use of the Term "Papilledema" in the Medical Literature: A Systematic Review of Case Reports across Specialties.

TOPIC: The term "papilledema" is often misused in different ways when describing nonintracranial pressure-related optic disc edema (ODE) or on fundoscopic examination. However, the extent of these errors is unknown among case reports. CLINICAL RELEVANCE: "Papilledema" refers to ODE secondary to raised intracranial pressure (ICP). Papilledema is a leading reason for referral to neuro-ophthalmologists. In any specialty setting, papilledema must be distinguished from other causes of ODE because it implies a unique pathophysiology and management strategy. If managed inappropriately, papilledema may cause permanent vision loss. METHODS: Cross-sectional evidence-based study with protocol registered on Open Science Framework (digital object identifier: 10.17605/OSF.IO/BUQS3). From Ovid MEDLINE and EMBASE, we included case reports with "papilledema" in their title, abstract, or article keywords between January 2011 and March 2022. Studies were graded for the following errors: type 1 (using "papilledema" without evidence of elevated ICP), type 2 (declaring "papilledema" on examination before finding evidence of elevated ICP), type 3 (both errors type 1 and 2), or no error. RESULTS: Among 722 case reports, there was a total of 482 errors (66.8%). There were 12 type 1 errors, 360 type 2 errors, 110 type 3 errors, and 240 studies with no errors. Ophthalmology, neurology, and neurosurgery were the most represented fields, yet only ophthalmology had a low prevalence of errors among all specialties. Regardless, all specialties with at least 10 included reports had a high error prevalence (>30%). Reduced error prevalence was significantly associated with higher impact factor journals, non-open-access publication models, and origin countries with an English official language. Error prevalence was not significantly associated with publication year. Also, the relationship between article citation counts and the prevalence of any type of error did not reach significance. Risk of bias analysis indicated that error occurrence was unrelated to the quality of case report study design. CONCLUSION: "Papilledema" is widely misused even among ophthalmology case reports. When allowed to propagate, this error can mislead care delivery to patients with ODE. Our results, although limited to case reports, indicate a need for more thorough peer-review standards and neuro-ophthalmology exposure in medical education.

The use of optical coherence tomography in neurology: a review.

Optical coherence tomography is a non-invasive, cost-efficient technique that provides high-resolution in vivo imaging of retinal tissue. The peripapillary retinal nerve fibre layer and macular ganglion cell complex are surrogate markers of neuroaxonal integrity in not only the eye, but also the CNS. Retinal atrophy may occur in tandem with CNS pathologies as a result of injury to ganglion cells, direct degeneration of the pregeniculate pathway, or retrograde trans-synaptic degeneration secondary to postgeniculate lesions. In this review, we outline the basic principles of optical coherence tomography and discuss its application to managing patients with demyelinating disorders, idiopathic intracranial hypertension, stroke, neurodegenerative conditions, and mitochondrial disorders. We demonstrate that measurements of peripapillary retinal nerve fibre layer and macular ganglion cell complex thickness are paramount in diagnosing and monitoring neurological disorders, including those with subclinical disease progression.

Dural Venous Sinus Thrombosis and Papilledema Related to JAK2 Mutation: A Case Series.

BACKGROUND: Dural venous sinus thrombosis (DVST) is an important cause of papilledema. Patients diagnosed with DVST should undergo work-up for underlying hypercoagulable state, including genetic causes. One important prothrombotic mutation is in the JAK2 gene, which is a driver of myeloproliferative neoplasms including polycythemia vera (PV). We aimed to determine the prevalence of JAK2 mutation in patients in presenting to neuro-ophthalmology clinic with DVST and papilledema. METHODS: Retrospective case series of patients seen in a tertiary neuro-ophthalmology practice who presented with papilledema due to DVST and were investigated for presence of JAK2 mutation. RESULTS: Four out of 15 patients with DVST (26%) were found to have JAK2 V617F mutation which led to subsequent diagnosis of PV in 2. One additional patient had a known diagnosis of essential thrombocytosis. We describe the clinical presentation of these four patients with papilledema and JAK2 mutation. CONCLUSIONS: A significant proportion of patients with papilledema secondary to DVST will harbor mutations in the JAK2 gene. Clinicians should be aware of this mutation as early testing will facilitate timely diagnosis and treatment of myeloproliferative disease to improve prognosis and reduce risk of recurrent thrombotic events.

Transsynaptic Ganglion Cell Degeneration in Adult Patients After Occipital Lobe Stroke.

BACKGROUND: Loss of retinal ganglion cells after occipital lobe damage is known to occur through transsynaptic retrograde degeneration in congenital lesions; however, studies of this phenomenon in acquired pathology, such as strokes affecting postgenicular visual pathway, are scant. We studied a cohort of adult patients with known onset of occipital lobe stroke to look for the presence, rate, and timing of macular ganglion cell loss on optical coherence tomography. METHODS: Retrospective review of patients seen in tertiary neuro-ophthalmology practice with homonymous hemianopia secondary to occipital lobe stroke of known onset. Optical coherence tomography of the macular ganglion cell complex (GCC) was performed, and hemifields corresponding to the side of the visual field (VF) defect were compared with the control retinal hemifield. RESULTS: Fifteen patients with homonymous VF defects were included in the study, and 8 of these (53.3%) demonstrated GCC hemifield thickness of less than 90% on the side corresponding to VF loss including 2/9 (22%) patients who had a stroke less than 2.5 years ago and 6/6 (100%) patients who had a stroke longer than 2.5 years ago. The amount of hemifield atrophy correlated to the logarithm of time since stroke onset ( P =0.030) but not age ( P = 0.95) or mean deviation on VF ( P = 0.19). Three patients with longitudinal data showed GCC thinning rates of 1.99, 5.13, and 5.68 µm per year. CONCLUSION: Transsynaptic retrograde degeneration occurs after occipital lobe stroke as early as 5.5 months after injury and was observed in all patients 2.5 years after stroke.

Visual Recovery in 2 Cases of Central Retinal Artery Occlusion Treated With Prompt Intra-ophthalmic Artery Fibrinolysis.

BACKGROUND: Central retinal artery occlusion (CRAO) rapidly produces inner retinal ischemia and irreversible vision loss. Although many therapeutic interventions have been proposed, no interventions have proven effective in restoring vision in large randomized controlled trials and final visual outcome in most patients is very poor. METHODS: Retrospective case series. RESULTS: We describe 2 cases of CRAO occurring after uncomplicated cataract surgery under topical anesthesia and rapidly diagnosed. Both had very severe vision loss at presentation with dramatic improvement after intra-ophthalmic artery fibrinolysis administered 2.75 and 5.5 hours after symptom onset. CONCLUSIONS: Sudden monocular vision loss is an ophthalmologic emergency as CRAO must be ruled out and if diagnosed, rapid intervention should be performed. Devastating vision loss can be prevented if interventional neuroradiology is trained and available on a 24-hour basis for administration of local intra-arterial thrombolysis.

Asymptomatic Fellow Eye Involvement in Nonarteritic Anterior Ischemic Optic Neuropathy.

BACKGROUND: Sequential nonarteritic anterior ischemic optic neuropathy (NAION) has been reported to occur in approximately 15% of patients within 5 years of the first episode. However, the incidence of presumed previous asymptomatic episode of NAION in fellow eye of patients presenting with acute NAION has not been previously reported. We reviewed charts of patients with acute NAION seen over a 5-year period to determine the frequency of visual field (VF) defect in the fellow eye secondary to presumed previous asymptomatic episode of NAION. METHODS: Retrospective chart review of all patients presenting to single, tertiary university-affiliated neuro-ophthalmology practice from January 2016 to September 2021 with diagnosis of acute NAION. Patients were determined to have had a presumed previous episode of asymptomatic NAION in the fellow eye if VF defect and corresponding optic nerve head pallor as well as thinning on peripapillary ocular coherence tomography (OCT) and ganglion cell analysis of macular complex were present and alternate causes of VF were excluded. RESULTS: One hundred ninety-two patients with the diagnosis of acute NAION were identified. One hundred thirty-nine had reliable VFs and were included in this study. VF defects in the fellow eye were present in 63 patients (45.4%). Of these, 54 (39%) were determined to represent previous NAION. In 14 of 139 patients (10%), a presumed episode of previous NAION in the fellow eye was asymptomatic. The most prevalent defect in asymptomatic eye was inferior altitudinal defect sparing fixation (7 of 14, 50%). The presence of obstructive sleep apnea, hypertension, diabetes, age, or sex was not predictive of previous episode of asymptomatic NAION. CONCLUSION: Unrecognized presumed previous episode of NAION occurred in a significant proportion of patients with acute NAION (14 of 139, 10.1%). In 100% of cases, the VF defect in the asymptomatic fellow eye was in a hemifield where there was a new loss in the symptomatic eye.

Diagnostic Yield of Investigations in Symmetric Optic Neuropathy.

BACKGROUND: Symmetric optic neuropathy (SON) is commonly seen in neuro-ophthalmic practice and is often discovered incidentally. Although multiple investigations might be performed to discover the underlying cause, they are not always indicated. The aim of this study was to report a clinically reasonable and cost-effective approach to investigating patients with SON. METHODS: SON was defined as bilateral optic neuropathy with normal and/or symmetrically decreased central visual acuity, absence of relative afferent pupillary defect, presence of symmetric optic disc pallor, symmetric thinning of peripapillary retinal nerve fiber layer on optical coherence tomography, and absence of other identifiable causes of optic neuropathy. Records of all patients diagnosed with SON seen at a tertiary university-affiliated neuro-ophthalmology practice from 2016 to 2022 were reviewed to identify the yield of various investigations. Clinical data from the initial and last follow-up visit were obtained. Subgroup analysis was performed to ascertain whether diagnostic yield is higher in patients with severe visual loss (central acuity worse than 20/40) compared with those with mild visual loss (acuity 20/40 or better). RESULTS: One hundred thirty-six patients met inclusion criteria. Testing for OPA1 and OPA2 mutations had the highest diagnostic yield (16.0%), followed by mitochondrial genome sequencing (13.6%), serum vitamin B12 (6.1%), and serum folate (1.6%). MRI brain was performed in 54.4% of patients and had a diagnostic yield of only 5%. Both patients who had abnormal MRI had symptoms of demyelination at presentation. Patients were followed for a mean of 15.0 (SD 21.3) months. The most frequently identified etiologies of SON were Leber hereditary optic neuropathy (8.1%), alcohol/tobacco amblyopia (7.4%), vitamin B12 deficiency (5.9%), and dominant optic atrophy (2.9%). Patients with severe visual impairment were more likely to have a final diagnosis compared with those with milder visual impairment (63.9% vs 12.0%, P < 0.001). CONCLUSIONS: The diagnostic yield of investigating SON in patients with preserved visual function, normal diet, and absence of other neurological symptoms is very low. It is reasonable to observe patients with SON with mild visual impairment, reserving costly investigations for those with the visual acuity worse than 20/40 or progressive course.

Swelling of Atrophic Optic Discs in Idiopathic Intracranial Hypertension.

BACKGROUND: Monitoring patients with idiopathic intracranial hypertension (IIH) and optic atrophy may be difficult as papilledema may not be appreciable on ophthalmoscopy. This retrospective chart review evaluated whether papilledema recurrence can be detected in this population using optical coherence tomography (OCT). METHODS: Serial clinical assessments, ophthalmoscopy, and peripapillary OCT were reviewed in a cohort of patients with IIH and optic atrophy. Atrophy was defined as moderate if average peripapillary retinal nerve fiber layer (pRNFL) thickness was ≤80 µm and severe if average pRNFL thickness was ≤60 µm on at least 2 consecutive high-quality OCT scans. Based on the upper tolerance limit of test-retest variability, mean pRNFL elevation of ≥6 µm with subsequent decrease to baseline thickness was considered papilledema. RESULTS: In a cohort of 165 patients with IIH, 32 eyes of 20 patients and 22 eyes of 12 patients demonstrated moderate and severe optic atrophy, respectively. Over a median follow-up of 198.5 weeks (range, 14.0-428.9), 63.3% (19 of 30) of patients had at least 1 episode of relapse, and 50.0% (15 of 30) had at least 1 episode of papilledema. There was a total of 36 relapse episodes, of which 7 occurred in patients with clinical signs and symptoms but no OCT evidence of relapse, 12 occurred in patients with OCT changes but no clinical signs and symptoms of relapse, and 17 occurred in patients with both clinical and OCT evidence to support relapse. The median percent pRNFL increase in the latter 2 groups was 13.7% (range, 7.5-111.8), and 7 eyes (13.0%) of 5 patients (16.7%) showed thickening greater than 20.0% from baseline. The rate, magnitude, and concordance of pRNFL swelling were similar between moderately vs severely atrophic eyes. CONCLUSIONS: Papilledema recurrence can be detected in atrophic optic discs using OCT. All patients with atrophic IIH should be longitudinally monitored with pRNFL measurement. Concurrence of other relapse-suggestive features should prompt further evaluation.

Obstructive Sleep Apnea in Men With Idiopathic Intracranial Hypertension: A Prospective Case-Control Study.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is uncommon in men. Previous studies reported on high frequency of obstructive sleep apnea (OSA) in men with IIH, but the pathophysiology of this association remains unclear. One possible culprit for increased intracranial pressure in patients with OSA is hypercapnia. The purpose of this study was to compare the rate of hypercapnia during polysomnography (PSG) study in men with and without IIH and to report on the rate and severity of OSA in men with IIH compared with control subjects of similar age and body mass index (BMI). METHODS: Prospective case-control study of male patients diagnosed with IIH underwent PSG with continuous oxygen and carbon dioxide monitoring overnight. Healthy control subjects with similar age and BMI also underwent PSG. The incidence of OSA diagnosis, rate of hypercapnia and hypoxia, and apnea hypopnea index (AHI) were compared between 2 groups. RESULTS: Eleven subjects with IIH and 10 controls underwent PSG. Both groups were similar regarding age and BMI on the Mann-Whitney U test ( P = 0.072 for age, P = 0.251 for BMI). Subjects for whom carbon dioxide data were not available for more than 50% of total sleep time were excluded from hypercapnia analysis. The mean age was 41.9 years, and the mean BMI was 33.8 kg/m 2 in subjects and controls. OSA was diagnosed in 9 of 11 men with IIH and 4 of 10 controls. There was no statistically significant difference in the rate of hypercapnia and hypoxia between 2 groups for whom the data were available. All patients with BMI over 30 kg/m 2 (7 of 7) and 50% (2 of 4) controls with BMI over 30 kg/m 2 were diagnosed with OSA compared with 50% (2 of 4) of cases and 33% (2 of 6) of controls with BMI less than 30 kg/m 2 . BMI was a significant predictor of total AHI ( P = 0.042) and OSA severity ( P = 0.023), but IIH diagnosis was not ( P > 0.05). CONCLUSIONS: There was no difference in hypercapnia rate between men with IIH and controls; thus, hypercapnia is an unlikely causative factor in pathophysiology of IIH. OSA on PSG was almost 2 times as prevalent in patients with IIH compared with controls; however, BMI was the strongest predictor of OSA diagnosis, and most patients (9 of 11) with BMI over 30 kg/m 2 had OSA on PSG. In men with BMI less than 30, the rate of OSA on PSG study was higher in men with IIH. Based on these data, we recommend that all men with the diagnosis of IIH should undergo PSG study.

Idiopathic Intracranial Hypertension and Socioeconomic Status in the Greater Toronto Area, Canada.

BACKGROUND: Previous studies have identified an association between obesity and socioeconomic variables such as poverty, minority status, and a low level of education. Because obesity is a major risk factor for the development of idiopathic intracranial hypertension (IIH), this study aims to identify and assess relationships between socioeconomic and geographic variables in patients with IIH in Canada. METHODS: A retrospective chart review was performed to identify female patients with IIH presenting to 2 neuro-ophthalmology clinics in Toronto between 2014 and 2022. Consecutive female patients younger than 50 years who did not have IIH were identified as controls. Patient age, body mass index (BMI), and postal code were obtained from electronic medical records. Patient postal codes were then converted to geographic dissemination areas based on the 2016 Canadian census, and data on socioeconomic outcomes were collected from Statistics Canada. RESULTS: Three hundred twenty-two female patients with IIH (mean age: 32.3 ± 10) and 400 female controls (mean age: 33.9 ± 9) were included. The mean BMI was 35.0 ± 8 for patients with IIH and 26.7 ± 7 for control patients ( P < 0.00001). There was a significant difference between dissemination areas resided by patients with IIH and control patients for median income ($34640 vs $36685 CAD, P = 0.02) and rate of postsecondary degree attainment (57.7% vs 60.5%, P = 0.01). There were no significant differences in the percentage of visible minorities, percentage of immigrants, knowledge of official languages, percentage of married individuals, average household size, or unemployment rate. There was a weak but significant inverse relationship between the rate of postsecondary degree attainment in dissemination areas resided by patients with IIH and their BMI ( P = 0.01, R 2 = 0.02). CONCLUSION: Patients with IIH reside in geographic areas with lower average levels of income and education than control patients. Patients with lower levels of education may be at higher risk of elevated BMI and therefore disease incidence and progression.

Maculopathies Referred to Neuro-Ophthalmology Clinic as Optic Neuropathies: A Case Series.

BACKGROUND: The clinical features of maculopathies and optic neuropathies often overlap: Both present with decreased visual acuity and variable loss of color vision; thus, maculopathy can be misdiagnosed as optic neuropathy, leading to patient harm. We aimed to determine what findings and/or tests were most helpful in differentiating between optic neuropathy and maculopathy. METHODS: A retrospective chart review of consecutive patients over 4.5 years who were referred to neuro-ophthalmology clinics with the diagnosis of optic neuropathy but whose final diagnosis was maculopathy. Patient demographics, mode of presentation, clinical profile, complete ophthalmological examination, results of all ancillary testing, and final diagnosis were recorded. RESULTS: A total of 47 patients (27 women) were included. The median age was 55 years (range, 18-85). Most referrals were by ophthalmologists (72.3%) and optometrists (12.8%). The diagnosis of maculopathy was made in 51.1% of patients at the time of first neuro-ophthalmic consultation. Only 6.4% patients (3) had relative afferent pupillary defect. Benign disc anomalies (tilted, myopic, small, or anomalous discs) were present in 34.0%, and 21.3% had pathologic disc changes unrelated or secondary to maculopathy. Macular ocular coherence tomography (OCT) was abnormal in 84.4% (with outer retinal pathology in 42.2% and inner retina pathology in 17.8%). Retinal nerve fiber layer (RNFL) thickness was normal in 82.6% of patients. CONCLUSIONS: Macular OCT is a high-yield test in differentiating between optic neuropathy and maculopathy and should be obtained in patients with suspected optic neuropathies who have normal RNFL thickness. Macular dystrophies, particularly cone dystrophies, unspecified retinal disorders, and macular degeneration were the most common mimics of optic neuropathy. The diagnosis was often present on OCT of the macula. The presence of coexistent benign and pathological disc anomalies may lead to maculopathy being misdiagnosed as optic neuropathy.

Unilateral Pendular Nystagmus in Multiple Sclerosis: A Case Series.

BACKGROUND: Acquired pendular nystagmus is most often seen in patients with demyelinating disease. Although it is often bilateral, rare cases may be monocular. There is paucity of data on the spectrum of clinical presentation, underlying mechanism, and response to treatment in patients with monocular pendular nystagmus. METHODS: Retrospective case series of patients with monocular pendular nystagmus seen in 2 tertiary neuro-ophthalmology clinics between January 2019 and June 2022. All patients underwent a complete neuro-ophthalmological assessment and MRI. RESULTS: We describe 5 patients (3 women) aged 31-49 with monocular pendular nystagmus. All had a diagnosis of multiple sclerosis. Three patients had horizontal and 2 had vertical pendular nystagmus. The Snellen visual acuity in the eye with pendular nystagmus varied from 20/20 to 20/200. Two patients were asymptomatic and 3 suffered visually debilitating oscillopsia. Treatment response was available for 2 patients, both of which responded well to treatment with memantine. The pendular nystagmus was observed in the eye with worse visual acuity in 4 of 5 cases (80%). Three patients had bilateral pontine lesions, and 2 had unilateral pontine lesion ipsilateral to the side of nystagmus. CONCLUSIONS: Monocular pendular nystagmus in adults is seen most often in patients with multiple sclerosis. Asymmetry in brainstem lesions and afferent visual input may be the culprit. Treatment with memantine may result in significant improvement in symptomatic patients.

Comparison of Idiopathic Intracranial Hypertension Patients With and Without Anemia.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a condition of elevated intracranial pressure without an identifiable cause. It mostly affects young obese women but has been reported in individuals newly diagnosed with anemia or with chronic anemia. The relationship between anemia and IIH is not well elucidated. This study aims to characterize the course of IIH in anemic patients. METHODS: Consecutive patients with IIH were recruited from neuro-ophthalmology clinics. Subsequent retrospective chart review obtained information on symptoms, complete blood counts (CBCs), visual acuity, visual fields, and optic disc edema at baseline and follow-up. Anemia was diagnosed by hemoglobin <120 g/L (women) and <130 g/L (men). RESULTS: One hundred twenty-three patients with IIH were recruited for this study, and 22.8% (28/123) had anemia. More anemic individuals had mild-to-moderate visual acuity impairment (logarithm of minimum angle of resolution 0.3-1, P = 0.01) and worse automated mean deviation ( P = 0.048). The median follow-up time was 47.4 weeks (interquartile range:20.1-91.8). Fifteen of 28 patients with anemia received anemia treatment and showed a trend toward increased hemoglobin. At follow-up, there were no differences in the visual acuity, but patients with anemia had worse automated mean deviation on visual fields ( P = 0.045). CONCLUSIONS: IIH patients with anemia had worse visual function at presentation and worse final visual field parameters. This suggests that CBCs should be obtained for patients with papilledema because it may influence final visual outcome.

Anemia and Idiopathic Intracranial Hypertension: A Case-Control Study.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a condition that mostly affects obese women of childbearing age but has been reported to be temporally related to new diagnoses of anemia. Despite these reports, the association between anemia and IIH remains controversial. The present study aimed to understand the strength of association between anemia and IIH through a case-control design. METHODS: Consecutive IIH patients were recruited from neuro-ophthalmology clinics and matched by age and sex to consecutive patients attending neuro-ophthalmology clinics with diagnoses other than IIH. Complete blood counts (CBCs) were reviewed within 6 months of neuro-ophthalmology presentation, and anemia was diagnosed by hemoglobin of <120 g/L in women and <130 g/L in men. Anemia was classified as microcytic (mean corpuscular volume (MCV) < 80 fL), normocytic (MCV 80-100 fL), and macrocytic (MCV > 100 fL) as well as mild (hemoglobin >110 g/L), moderate (hemoglobin 80-109 g/L), and severe (hemoglobin <80 g/L). RESULTS: One hundred twenty-three IIH patients and 113 controls were included in the study. More IIH patients than controls had anemia (22.8%, 28/123 vs 10.6%, 12/113, P = 0.01) with an odds ratio of 2.48 (95% CI: 1.19, 5.16). There were no differences in severity of anemia or MCV between IIH patients and controls, with anemia most often being mild (57.1%, 16/28 vs 75%, 9/12) and normocytic (50.0%, 14/28 vs 50.0%, 6/12). However, 17.9% (5/28) of IIH patients had severe anemia compared with zero in the control group. IIH patients had a higher mean platelet count than controls ( P < 0.001), and there were no differences on leukocyte counts. CONCLUSION: Idiopathic intracranial hypertension patients have a higher prevalence of anemia compared with non-IIH neuro-ophthalmology patients. The anemia was mostly mild and may be explained by other factors related to worse health status and obesity, including low socioeconomic status, poor nutrition, and polycystic ovary syndrome. However, as a CBC is a widely available test and anemia may influence the IIH disease course, we propose that this test be obtained in all patients with new papilledema.