ABSTRACT
Introduction: Ocular myasthenia gravis (OMG) is a common condition of the neuromuscular junction that may convert to generalized myasthenia gravis (GMG). Our aim in this study was to ...determine the conversion rate and predictive factors for generalization in OMG, in an Asian population. Methods: The investigation consisted of a retrospective study of OMG patients with a minimum 2 years of follow‐up. Results: Among 191 patients with OMG, 155 had the minimum 2‐year follow‐up. The conversion rate at median follow‐up (40.8 months) was 10.6% (95% confidence interval 7.9%–13.3%), and at the 2‐year follow‐up it was 7.7% (95% confidence interval 5.6%–9.8%). At baseline, the predictive factors for generalization were positive acetylcholine receptor antibodies (hazard ratio 3.71, P = 0.024), positive repetitive nerve stimulation (RNS) studies (hazard ratio 4.42, P = 0.003), and presence of radiologically presumed or pathologically confirmed thymoma (hazard ratio 3.10, P = 0.013). Discussion: The conversion rate of OMG to GMG in Asian patients is low, as predicted by presence of acetylcholine receptor antibodies, presence of thymoma, and positive RNS studies. Muscle Nerve 57: 756–760, 2018
In Memoriam: James Finbarr (Barry) Cullen Tow, Sharon L C; McIlwaine, Gawn G; Miller, Neil R
Journal of neuro-ophthalmology,
2021-Jun-01, 2021-06-00, Letnik:
41, Številka:
2
Journal Article
Abstract Background Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disease characterized by weakness of bodily skeletal muscles. Office-based diagnostic tests such as repetitive nerve ...stimulation (RNS), single fiber electromyography (SFEMG), and the ice test, are used to refine the differential clinical diagnosis of this disease. Evaluating the clinical sensitivity and specificity of these tests, however, may be confounded by lack of a gold standard, non-blinding, incorporation bias, use of non-representative populations and retrospective data. Objective In this study comprising a large Asian cohort of 127 patients recruited from a Neuro-ophthalmology clinic, we minimized aforementioned confounders and tested the diagnostic value of 3 office-based tests against 2 reference standards of MG by virtue of clinical features, antibody assay and response to treatment. Results Regardless of the reference standard used, the ice and SFEMG tests displayed a higher sensitivity (86.0 to 97.3%) compared to the RNS test (21.3 to 30.6%). Conversely, the specificity of the ice (31.3%) and SFEMG (21.7% and 17.2%) tests were reduced compared to the RNS test (82.6% and 84.4%). The combined use of the ice test and SFEMG, improved the specificity of MG diagnosis to 63.6% and 64.3%, without affecting the sensitivity of those tests. Conclusion Our findings indicate, in an Asian population, high sensitivity of the SFEMG test and suggest the ice test as a valid, affordable and less technically demanding approach to diagnose MG with ocular involvement. Both ice test and SFEMG alone, however, yielded poor specificity. We suggest that the combination of SFEMG and ice test provides a more reliable diagnosis of MG.
Optic neuritis (ON) may be the initial manifestation of neuromyelitis optica spectrum disorder (NMOSD). Aquaporin-4 antibody (AQP4 Ab) is used to diagnose NMOSD. This has implications on prognosis ...and is important for optimal management. We aim to evaluate if clinical features can distinguish AQP4 Ab seropositive and seronegative ON patients.
We reviewed patients with first episode of isolated ON from Tan Tock Seng Hospital and Singapore National Eye Centre who tested for AQP4 Ab from 2008 to 2017. Demographic and clinical data were compared between seropositive and seronegative patients.
Among 106 patients (120 eyes) with first episode of isolated ON, 23 (26 eyes; 22%) were AQP4 Ab positive and 83 (94 eyes; 78%) were AQP4 Ab negative. At presentation, AQP4 Ab positive patients had older mean onset age (47.9 ± 13.6 vs 36.8 ± 12.6 years, P < 0.001), worse nadir VA (OR 1.714; 95% CI, 1.36 to 2.16; P < 0.001), less optic disc swelling (OR 5.04; 95% CI, 1.682 to 15.073; p = 0.004), and higher proportions of concomitant anti-Ro antibody (17% vs 4%, p = 0.038) and anti-La antibody (17% vs 1%, p = 0.008). More AQP4 Ab positive patients received steroid-sparing immunosuppressants (74% vs 19%, p < 0.001) and plasma exchange (13% vs 0%, p = 0.009). AQP4 Ab positive patients had worse mean logMAR VA (visual acuity) at 12 months (0.70 ± 0.3 vs 0.29 ± 0.5, p = 0.051) and 36 months (0.37±0.4 vs 0.14 ± 0.2, p = 0.048) follow-up.
Other than older onset age and retrobulbar optic neuritis, clinical features are non-discriminatory for NMOSD. We propose a low threshold for AQP4 Ab serology testing in inflammatory ON patients, particularly in high NMOSD prevalence populations, to minimize diagnostic and treatment delays.
Here we report a case of sudden, unilateral, painless visual loss in a middle-aged patient. A 45-year-old gentleman with no known past medical history presented with acute painless left visual ...impairment. Clinically, he was found to have a left optic neuropathy associated with a swollen and hyperemic left optic disc. The right optic disc was noted to be small and crowded, and both optic discs were noted to have irregular margins. Humphrey perimetry revealed a constricted visual field in the left eye. Fundus autofluorescence imaging revealed autofluorescence, and B-scan ultrasonography showed hyperreflectivity within both nerve heads. Blood investigations for underlying ischemic and inflammatory markers revealed evidence of hyperlipidemia but were otherwise normal. A diagnosis of left nonarteritic anterior ischemic optic neuropathy (NAAION) was made, with associated optic disc drusen and hyperlipidemia. NAAION typically occurs in eyes with small, structurally crowded optic discs. The coexistence of optic disc drusen and vascular risk factors may further augment the risk of developing NAAION.
Purpose
Tuberculous optic neuropathy may follow infection with
Mycobacterium tuberculosis
or administration of the bacille Calmette–Guerin. However, this condition is not well described in the ...ophthalmic literature.
Methods
Ophthalmologists, identified through professional electronic networks or previous publications, collected standardized clinical data relating to 62 eyes of 49 patients who they had managed with tuberculous optic neuropathy.
Results
Tuberculous optic neuropathy was most commonly manifested as papillitis (51.6 %), neuroretinitis (14.5 %), and optic nerve tubercle (11.3 %). Uveitis was an additional ocular morbidity in 88.7 % of eyes. In 36.7 % of patients, extraocular tuberculosis was present. The majority of patients (69.4 %) had resided in and/or traveled to an endemic area. Although initial visual acuity was 20/50 or worse in 62.9 % of 62 eyes, 76.7 % of 60 eyes followed for a median of 12 months achieved visual acuities of 20/40 or better. Visual field defects were reported for 46.8 % of eyes, but these defects recovered in 63.2 % of 19 eyes with follow-up.
Conclusion
Visual recovery from tuberculous optic neuropathy is common, if the diagnosis is recognized and appropriate treatment is instituted. A tuberculous etiology should be considered when evaluating optic neuropathy in persons from endemic areas.
Photic stimulation of rods, cones and intrinsically photosensitive melanopsin-containing retinal ganglion cells (ipRGCs) mediates non-visual light responses, including entrainment of circadian ...rhythms and pupillary light reflex. Unlike visual responses to photic stimulation, the cerebral correlates of non-visual light responses in humans remains elusive. In this study, we used functional magnetic resonance imaging (fMRI) in 14 healthy young participants, to localize cerebral regions which are differentially activated by metameric light that gave rise to different levels of melanopic excitation. Mean blood oxygen-level dependent (BOLD) responses disclosed bilateral activation of the frontal eye fields during exposure to light geared towards melanopsin. Furthermore, multivariate pattern analyses showed distinct bilateral pattern activity in the inferior temporal gyri and the caudate nuclei. Taken together, our findings suggest that melanopsin-based photoreception activates a cerebral network including frontal regions, classically involved in attention and ocular motor responses.
•By combining metameric photic stimulations and fMRI, we disclose brain regions involved in melanopsin-based photoreception.•The bilateral frontal eye fields, inferior temporal gyri, and caudate nuclei, were differentially activated under differential stimulations.•Our findings suggest a role of ipRGCs in ocular motor responses and/or attention.
We performed a retrospective assessment of the long-term visual, neurologic, and systemic outcomes of 47 patients with anterior visual pathway gliomas seen at the Johns Hopkins Hospital. All of the ...patients had follow-up of at least 10 years or died during the follow-up period. Two patients died before 10 years of follow-up were achieved. The remaining 45 patients (including three patients who subsequently died) had follow-up of 10-28 years (mean, 15.3 years; median, 15 years). Sixteen of the patients in this study, most of whom had neurofibromatosis type 1 (NF1), received no treatment. None of these patients died or developed neurologic morbidity as a result of their tumor. Thirty-one of the patients, most of whom did not have evidence of NF1, received treatment. Many of these patients subsequently developed neurologic, endocrine, or visual morbidity. However, although patients with anterior visual pathway gliomas who were not treated fared better visually, neurologically, and systemically than patients who were treated, patients who required treatment for progression generally had a good overall prognosis, particularly patients with tumors that did not involve the hypothalamus. Most of these patients survived and maintained useful vision in at least one eye. We believe that patients with anterior visual pathway gliomas, particularly those with NF1, should not be treated unless there is clear clinical or neuroimaging evidence of progression.
To analyze the results of trabeculectomy performed for all cases of acute primary angle closure (APAC).
Retrospective, noncomparative case series
Fifty-six consecutive patients who underwent ...trabeculectomy for APAC at two Singapore centers from 1993 through 1995.
The conventional treatment for APAC is to lower intraocular pressure (IOP) medically, after which laser peripheral iridotomy (PI) is performed. However, in Asian eyes, the acute attack is often refractory to standard treatment. Trabeculectomy is occasionally performed on eyes that do not respond to medical therapy, as well as eyes with APAC that respond to medical therapy but are assessed as having underlying chronic angle-closure glaucoma. In such cases, laser PI is not performed before trabeculectomy.
The surgical outcome was assessed in terms of final IOP and the incidence of complications. Success was defined as final IOP less than 21 mmHg without medication, and qualified success was defined as final IOP less than 21 mmHg with medication. Patients whose IOP was more than 21 mmHg, required further glaucoma surgery, lost light perception, or whose eye became phthisical were classified as failures.
The mean follow up was 22 months (range, 6–42 months). In group A, the medical failure group (n = 32), success in IOP control was obtained in 18 patients (56.2%), qualified success was achieved in 3 patients (9.4%), and failure resulted in 11 patients (34.4%). Ten patients (31.3%) encountered early postoperative complications such as shallow anterior chamber. In group B, the medical success group (n = 24), success in IOP control was achieved in 21 patients (87.5%), qualified success was achieved in 3 patients (12.5%), and there were no cases of failure. The incidence of postoperative complications was low (4 eyes 16.7%). In terms of IOP outcome, trabeculectomy outcome was significantly worse in group A (
P < 0.001, Fisher’s exact test).
Because there is a high risk of surgical failure and complications, trabeculectomy may not be the procedure of choice in medically unresponsive cases of APAC.
The aim of the study is to examine the baseline intraocular pressure (IOP) and its changes after performing a water drinking test (WDT) in patients with unilateral hemifacial spasm (HFS).
In this ...prospective observational study, patients aged 21 years and above diagnosed with unilateral HFS were recruited from the Singapore National Eye Centre between January 2015 and August 2016. The unaffected eye of each patient served as a matched control. An interviewer-administered standardized questionnaire on HFS symptoms and ophthalmic examination was performed. Automated perimetry, optical coherence tomography (OCT) of the optic nerve head, color disc stereophotography and water drinking test (WDT) were done. The primary outcome measure was the difference in IOP between eyes affected by HFS and fellow eyes at baseline and at 15, 30 and 45 minutes of the WDT.
Fifty-four patients with unilateral HFS were included. Mean age was 59.8±9.9 years (range, 37.0-84.0). Of these, 54% were female and 94% were Chinese. Mean baseline IOP was significantly higher in eyes with HFS (13.9±3.1mmHg) compared to fellow eyes (13.3±2.8mmHg) (p=0.008). There was no significant difference in absolute or percentage change in IOP from baseline between the 2 groups at 15, 30 and 45 minutes of the WDT. Mean vertical cup-disc ratio (VCDR) on clinical examination was significantly higher in eyes with HFS (0.5±0.2) compared to fellow eyes (0.4±0.2) (p=0.02). There was no significant difference between the groups for visual field parameters and mean retinal nerve fiber layer thickness on OCT.
Hemifacial spasm is associated with a small but significant difference in mean baseline IOP and VCDR between affected and fellow eyes. However, when eyes affected by HFS and fellow eyes were challenged with the WDT, both responded in similar ways.
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