Optic Neuropathy and Myelopathy in a Teenager With Biotinidase Deficiency.

ABSTRACT: A 19-year-old man presented with 3 years of gradually progressive, painless vision loss in both eyes. The ophthalmic examination showed bilateral diminished visual acuity, dyschromatopsia, and temporal optic nerve pallor. The neurological examination was consistent with a mild myelopathy with decreased pin-prick sensation starting at T6-T7 and descending through the lower extremities. Hyperreflexia was also present in the lower more than upper extremities. Infectious, inflammatory, and nutritional serum workup and cerebrospinal fluid analysis were both unrevealing. MRI of the brain and spinal cord showed abnormal T2 hyperintensity of the fornix, corpus callosum, optic nerves, and lateral columns of the cervical and thoracic spine, with diffusion restriction in the inferior-posterior corpus callosum and fornix. Biotinidase serum enzyme activity was tested and showed a decreased level of activity. Biotinidase gene testing showed a homozygous pathogenic variant, c.424C>A (p.P142T), confirming the diagnosis of biotinidase deficiency and prompting oral biotin supplementation. Three months after starting treatment, the patient's visual acuity, color vision, visual fields, and MRI spine abnormalities all improved significantly. Biotinidase deficiency is an important diagnostic consideration in patients with unexplained optic neuropathy and/or myelopathy.

Establishing Optic Nerve Diameter Threshold Sensitive and Specific for Optic Atrophy Diagnosis.

PURPOSE: To determine a potential threshold optic nerve diameter (OND) that could reliably differentiate healthy nerves from those affected by optic atrophy (OA) and to determine correlations of OND in OA with retinal nerve fiber layer (RNFL) thickness, visual acuity (VA), and visual field mean deviation (VFMD). METHODS: This was a retrospective case control study. Magnetic resonance (MR) images were reviewed from individuals with OA aged 18 years or older with vision loss for more than 6 months and an OA diagnosis established by a neuro-ophthalmologist. Individuals without OA who underwent MR imaging of the orbit for other purposes were also collected. OND was measured on coronal T2-weighted images in the midorbital section, 1cm posterior to the optic disc. Measurements of mean RNFL thickness, VA and VFMD were also collected. RESULTS: In this study 47 OA subjects (63% women, 78 eyes) and 75 normal subjects (42.7% women, 127 eyes) were assessed. Healthy ONDs (mean 2.73 ± 0.24 mm) were significantly greater than OA nerve diameters (mean 1.94 ± 0.32 mm; P < 0.001). A threshold OND of ≤2.3 mm had a sensitivity of 0.92 and a specificity of 0.93 in predicting OA. Mean RNFL (r = 0.05, p = 0.68), VA (r = 0.17, p = 0.14), and VFMD (r = 0.18, p = 0.16) were not significantly associated with OND. CONCLUSION: ONDs are significantly reduced in patients with OA compared with healthy nerves. A threshold OND of ≤2.3 mm is highly sensitive and specific for a diagnosis of OA. OND was not significantly correlated with RNFL thickness, VA, or VFMD.

A multi-centre case series of patients with coexistent intracranial hypertension and malignant arterial hypertension.

OBJECTIVE: To describe the clinical characteristics, outcomes, and management of a large cohort of patients with concomitant malignant arterial hypertension and intracranial hypertension. METHODS: Design: Retrospective case series. SUBJECTS: Patients aged ≥ 18 years with bilateral optic disc oedema (ODE), malignant arterial hypertension and intracranial hypertension at five academic institutions. Patient demographics, clinical characteristics, diagnostic studies, and management were collected. RESULTS: Nineteen patients (58% female, 63% Black) were included. Median age was 35 years; body mass index (BMI) was 30 kg/m2. Fourteen (74%) patients had pre-existing hypertension. The most common presenting symptom was blurred vision (89%). Median blood pressure (BP) was 220 mmHg systolic (IQR 199-231.5 mmHg) and 130 mmHg diastolic (IQR 116-136 mmHg) mmHg), and median lumbar puncture opening pressure was 36.5 cmH2O. All patients received treatment for arterial hypertension. Seventeen (89%) patients received medical treatment for raised intracranial pressure, while six (30%) patients underwent a surgical intervention. There was significant improvement in ODE, peripapillary retinal nerve fibre layer thickness, and visual field in the worst eye (p < 0.05). Considering the worst eye, 9 (47%) presented with acuity ≥ 20/25, while 5 (26%) presented with ≤ 20/200. Overall, 7 patients maintained ≥ 20/25 acuity or better, 6 demonstrated improvement, and 5 demonstrated worsening. CONCLUSIONS: Papilloedema and malignant arterial hypertension can occur simultaneously with potentially greater risk for severe visual loss. Clinicians should consider a workup for papilloedema among patients with significantly elevated blood pressure and bilateral optic disc oedema.

Linezolid optic neuropathy.

PURPOSE OF REVIEW: In this article, we reviewed 67 reported cases of linezolid optic neuropathy and describe the common characteristics and expectations for recovery with an emphasis on recent findings in the literature. RECENT FINDINGS: Linezolid classically causes a reversible, duration-dependent optic neuropathy. However, in our review, we found only 66.7% of patients recovered complete visual function. Vision loss most commonly affected visual acuity followed by visual field and color vision. We also found patients taking higher doses of linezolid experienced full recovery less often, suggesting a dose-dependent component of linezolid optic neuropathy. Linezolid use has increased in frequency and duration, especially in the treatment of drug-resistant tuberculosis, and data indicate that these patients experience lower rates of complete vision recovery compared with patients taking linezolid for other indications. SUMMARY: Linezolid is an effective medication for treating drug-resistant infections; however, it may result in optic neuropathy. It is reasonable for patients on linezolid to undergo screening examinations, especially those on higher doses or for prolonged duration of therapy.

MRI Signal Intensity Varies Along the Course of the Normal Optic Nerve.

BACKGROUND: MRI can help distinguish various causes of optic neuropathy including optic neuritis. Importantly, neuromyelitis optica spectrum disorder (NMOSD) has a propensity to cause enhancement of the prechiasmatic optic nerves. To determine whether the prechiasmatic optic nerve (PC-ON) demonstrates a different intensity from the midorbital optic nerve (MO-ON) on MRI among patients without optic neuropathy. METHODS: Data were retrospectively obtained from 75 patients who underwent brain MRI for an ocular motor nerve palsy between January 2005 and April 2021. Inclusion criteria were patients aged 18 years or older with visual acuities of at least 20/25 and no evidence of optic neuropathy on neuro-ophthalmic examination. A total of 67 right eyes and 68 left eyes were assessed. A neuroradiologist performed quantitative intensity measurements of the MO-ON and PC-ON on precontrast and postcontrast T1 axial images. Normal-appearing temporalis muscle intensity was also measured and used as a reference to calculate an intensity ratio to calibrate across images. RESULTS: The mean PC-ON intensity ratio was significantly higher than the MO-ON intensity ratio on both precontrast (19.6%, P < 0.01) and postcontrast images (14.2%, P < 0.01). Age, gender, and laterality did not independently affect measurements. CONCLUSIONS: The prechiasmatic optic nerve shows brighter intensity ratios on both precontrast and postcontrast T1 images than the midorbital optic nerve among normal optic nerves. Clinicians should recognize this subtle signal discrepancy when assessing patients with presumed optic neuropathy.

Bilateral Simultaneous Nonarteritic Anterior Ischemic Optic Neuropathy: Demographics, Risk Factors, and Visual Outcomes.

BACKGROUND: Although nonarteritic anterior ischemic optic neuropathy is a well-known cause of vision loss, it typically presents unilaterally. Simultaneous, bilateral nonarteritic anterior ischemic optic neuropathy (sNAION) is rare and poorly studied in comparison. This study seeks to characterize the clinical features and risk factors of patients with sNAION compared with unilateral NAION (uNAION). METHODS: In this retrospective case-control study, we reviewed 76 eyes (38 patients) with sNAION and 38 eyes (38 patients) with uNAION (controls) from 4 academic institutions examined between 2009 and 2020. Demographic information, medical history, medication use, symptom course, paraclinical evaluation, and visual outcomes were collected for all patients. RESULTS: No significant differences were observed in demographics, comorbidities and their treatments, and medication usage between sNAION and uNAION patients. sNAION patients were more likely to undergo an investigative work-up with erythrocyte sedimentation rate measurement ( P = 0.0061), temporal artery biopsy ( P = 0.013), lumbar puncture ( P = 0.013), and MRI ( P < 0.0001). There were no significant differences between the 2 groups for visual acuity, mean visual field deviation, peripapillary retinal nerve fiber layer thickness, or ganglion cell-inner plexiform layer thickness at presentation, nor at final visit for those with ≥3 months of follow-up. The sNAION eyes with ≥3 months of follow-up had a smaller cup-to-disc ratio (CDR) at final visit ( P = 0.033). Ten patients presented with incipient NAION, of which 9 suffered vision loss by final visit. CONCLUSION: Aside from CDR differences, the risk factor profile and visual outcomes of sNAION patients seem similar to those of uNAION patients, suggesting similar pathophysiology.

Idiopathic horner syndrome diagnosed remotely using telemedicine.

Idiopathic Horner Syndrome Diagnosed Remotely using Telemedicine. The novel Coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), pandemic has altered the field of ophthalmology in myriad ways. During the initial lockdown period in March, the use of telemedicine expanded to adhere to public health guidelines. The field of neuro-ophthalmology is an ophthalmic sub-specialty less prone to the use of telemedicine. We present a case of isolated idiopathic Horner syndrome in a 39 year old female diagnosed through telemedicine.

Red Desaturation Prevalence and Severity in Healthy Patients.

Background and Objectives: To determine the percentage of the healthy population that responds asymmetrically to the red desaturation test and to approximate the degree of red desaturation in those individuals. We also sought to elucidate any correlation between demographic variables and red desaturation prevalence and severity. Methods: Adults aged 18 years and older with a normal eye examination, including confrontation fields and best-corrected visual acuity of ≥20/25 in both eyes, were eligible for this prevalence study. Those with objective or subjective afferent visual dysfunction were excluded. A total of 101 eligible participants (68.3% female and 31.7% male; racial/ethnic breakdown of 77.2% White, 11.9% Black, 8.9% Asian, 2.0% N/A; mean (SD) age: 41.5 (15.3) years) were queried whether the monocular perception of redness of a standardized tropicamide bottle cap was the same and to estimate the interocular percentage difference, with 1 eye perceiving the bottle cap at "100% redness." Results: Twenty-four participants (23.8%) experienced some degree of red desaturation. For these individuals with red desaturation, the average interocular difference was 9.0% (range 2%-25%, 95% confidence interval 6.0%-12.0%). There was no statistical evidence for a relationship between red desaturation and race, sex, or age. Discussion: This study shows that nearly a quarter of healthy patients without apparent optic nerve or macular dysfunction may recognize red desaturation. This deserves consideration when interpreting red desaturation testing in patients suspected to have unilateral optic neuropathy. Further research with larger sample sizes may identify predictors of red desaturation in healthy patients, establish the red desaturation threshold separating pathologic from physiologic phenomena, and assess the repeatability of red desaturation over time in affected individuals.

Delayed-Onset Inflammatory Optic Nerve Sheath Mass and Perineuritis Following Cessation of Ipilimumab and Nivolumab Therapy.

A 65-year-old male presented with headaches and painless episodes of unilateral vision loss. He had a history of renal cell carcinoma, in remission following surgery and immunotherapy with ipilimumab and nivolumab, discontinued 2 years and 3 months before presentation, respectively. MRI revealed an optic nerve sheath mass and perineuritis. After 1 month of corticosteroid therapy, there was a robust clinical and radiographic response, which relapsed dramatically following cessation. An optic nerve sheath biopsy showed chronic mild inflammation, and extensive work-up for alternative etiologies of orbital inflammation was negative. Following a prolonged taper of corticosteroids, he demonstrated complete response. In the setting of ocular immune privilege, ophthalmic immune-related adverse events (irAE) are rare, although multifarious. While on-treatment irAE are well-characterized, posttreatment irAE have become increasingly recognized across multiple organ systems. We report a case of a delayed-onset inflammatory optic nerve sheath mass and perineuritis after cessation of immunotherapy.

Heart rate and age modulate retinal pulsatile patterns.

Theoretical models of retinal hemodynamics showed the modulation of retinal pulsatile patterns (RPPs) by heart rate (HR), yet in-vivo validation and scientific merit of this biological process is lacking. Such evidence is critical for result interpretation, study design, and (patho-)physiological modeling of human biology spanning applications in various medical specialties. In retinal hemodynamic video-recordings, we characterize the morphology of RPPs and assess the impact of modulation by HR or other variables. Principal component analysis isolated two RPPs, i.e., spontaneous venous pulsation (SVP) and optic cup pulsation (OCP). Heart rate modulated SVP and OCP morphology (pFDR < 0.05); age modulated SVP morphology (pFDR < 0.05). In addition, age and HR demonstrated the effect on between-group differences. This knowledge greatly affects future study designs, analyses of between-group differences in RPPs, and biophysical models investigating relationships between RPPs, intracranial, intraocular pressures, and cardiovascular physiology.

Ophthalmic Findings Associated with NEDD4L-related Disorder.

Pathogenic variants in the NEDD4L gene are associated with a very rare neurodevelopmental disorder characterized by periventricular nodular heterotopia, developmental delay, 2-3 toe syndactyly, and cleft palate. Ophthalmic findings associated with this disorder have not been well described in literature. We have summarized the clinical findings that have been reported in this disorder previously and highlight a novel ophthalmic finding of foveal hypoplasia in a new case of NEDD4L-related disorder.

Ganglion Cell Layer Thickness Variance Using SPECTRALIS Optical Coherence Tomography.

BACKGROUND: To determine the normal variance of the mean macular ganglion cell layer (GCL) volume among subjects without significant ocular pathology using SPECTRALIS optical coherence tomography (OCT). METHODS: Fifty subjects underwent a baseline scan using SPECTRALIS OCT followed by 2 more studies with (reg-ON) and without (reg-OFF) eye registration all taken at the same session. The mean GCL volume was measured using built-in SPECTRALIS software. Eyes with macular pathology were excluded. The reproducibility of the measurements of the GCL volume was evaluated with Bland-Altman plots and limits of agreement, intraclass correlation coefficient (ICC), and the coefficient of repeatability (CR). RESULTS: A total of 98 eyes met criteria for the analysis. The mean GCL volume difference was 0.0002 ± 0.029 and -0.0005 ± 0.035 mm 3 for scans 1 versus 2 (baseline vs reg-ON) and 3 (baseline vs reg-OFF), respectively. The ICCs were 0.985 and 0.977 for the baseline vs reg-ON and reg-OFF groups. The CR for baseline vs reg-ON was 0.056 while CR for baseline vs reg-OFF was 0.069. Ninety percent of eyes fell within 0.04 mm 3 of test-retest reliability. CONCLUSIONS: Our model found a predictable threshold of 0.07 mm 3 or less for SPECTRALIS OCT mean GCL volume variance, which did not significantly change with eye registration in eyes without macular pathology. Clinicians may also consider a threshold of 0.04 mm 3 when determining stable vs progressive changes in mean GCL volume using this device.

Proceedings of the 43nd Annual Upper Midwest Neuro-Ophthalmology Group Meeting, July 23, 2021 and Second Virtual Upper Midwest Neuro-Ophthalmology Group Meeting.

The 43rd meeting of the Upper Midwest Neuro-Ophthalmology Group (UMNOG) took place on July 23, 2021. For the second sequential year, the meeting was held virtually due to the COVID-19 pandemic. The meeting was held in the honour of the late Ivy Dreizin MD. Ninety people attended virtually marking the highest UMNOG meeting attendance on record. There were 23 podium presentations interspersed with numerous personal testimonials recognising Dr Dreizin and her immense contributions to the UMNOG community.

Downbeat nystagmus: a clinical review of diagnosis and management.

PURPOSE OF REVIEW: This review will extensively cover the clinical manifestations, causes, diagnostic evaluation, and management strategies of downbeat nystagmus (DBN). RECENT FINDINGS: Historically, MRI to assess for structural lesions at the cervicomedullary junction has been the primary diagnostic test in the evaluation of DBN since the 1980s. In recent years, there is increasing awareness of nonstructural causes of DBN including gluten ataxia, nutritional deficiencies, and paraneoplastic syndromes, among others. Medical management with aminopyridines has become first-line therapy in addition to disease-specific therapies. SUMMARY: DBN is a common form of acquired nystagmus and the differential diagnosis remains broad, including both benign and potentially fatal causes. For practical purposes, the causes can be categorized as structural vs. nonstructural with MRI as the ideal, initial diagnostic study to differentiate the two. General therapeutic options include pharmacotherapy to enhance Purkinje cell function, strabismus surgery or prisms to shift null points, and behavioural changes. Disease-specific treatment is necessarily broad, though a significant proportion of patients will be idiopathic.