Crandall Peeler

Clinical Utility of Acetylcholine Receptor Antibody Testing in Ocular Myasthenia Gravis

IMPORTANCE The sensitivity of acetylcholine receptor (AChR) antibody testing is thought to be lower in ocular myasthenia gravis (OMG) compared with generalized disease, although estimates in small-scale studies vary. There is little information in the literature about the implications of AChR antibody levels and progression from OMG to generalized myasthenia gravis. OBJECTIVES To test the hypothesis that serum AChR antibody testing is more sensitive in OMG than previously reported and to examine the association between AChR antibody levels and progression from OMG to generalized myasthenia gravis. DESIGN, SETTING, AND PARTICIPANTS A retrospective, observational cohort study was conducted of 223 patients (mean [SD] age, 59.2 [16.4] years; 139 [62.3%] male) diagnosed with OMG between July 1, 1986, and May 31, 2013, at 2 large, academic medical centers. MAIN OUTCOMES AND MEASURES Baseline characteristics, OMG symptoms, results of AChR antibody testing, and progression time to generalized myasthenia gravis (if this occurred) were recorded for each patient. Multiple logistic regression was used to measure the association between all clinical variables and antibody result. Kaplan-Meier survival analysis was performed to examine time to generalization. RESULTS Among the 223 participants, AChR antibody testing results were positive in 158 participants (70.9%). In an adjusted model, increased age at diagnosis (odds ratio [OR], 1.03; 95% CI, 1.01-1.04; P = .007) and progression to generalized myasthenia gravis (OR, 2.92; 95% CI, 1.18-7.26; P = .02) were significantly associated with positive antibody test results. Women were less likely to have a positive antibody test result (OR, 0.36; 95% CI, 0.19-0.68; P = .002). Patients who developed symptoms of generalized myasthenia gravis had a significantly higher mean (SD) antibody level than those who did not develop symptoms of generalized myasthenia gravis (12.7 [16.5] nmol/L vs 4.2 [7.9] nmol/L; P = .002). CONCLUSIONS AND RELEVANCE We demonstrate a higher sensitivity of AChR antibody testing than previously reported in the largest cohort of patients with OMG available to date. Older age, male sex, and progression to generalized myasthenia gravis were significantly associated with a positive antibody test result. In addition, to our knowledge, this is the first report of an association between high AChR antibody levels and progression from OMG to generalized disease.

Digital Quantification of Goldmann Visual Fields (GVFs) as a Means for Genotype–Phenotype Comparisons and Detection of Progression in Retinal Degenerations

PURPOSE To develop a reliable and efficient digital method to quantify planimetric Goldmann visual field (GVF) data to monitor disease course and treatment responses in retinal degenerative diseases. METHODS A novel method to digitally quantify GVFs using Adobe Photoshop CS3 was developed for comparison to traditional digital planimetry (Placom 45C digital planimeter; Engineer Supply, Lynchburg, Virginia, USA). GVFs from 20 eyes from 10 patients with Stargardt disease were quantified to assess the difference between the two methods (a total of 230 measurements per method). This quantification approach was also applied to 13 patients with X-linked retinitis pigmentosa (XLRP) with mutations in RPGR. RESULTS Overall, measurements using Adobe Photoshop were more rapidly performed than those using conventional planimetry. Photoshop measurements also exhibited less inter- and intraobserver variability. GVF areas for the I4e isopter in patients with the same mutation in RPGR who were nearby in age had similar qualitative and quantitative areas. CONCLUSIONS Quantification of GVFs using Adobe Photoshop is quicker, more reliable, and less user dependent than conventional digital planimetry. It will be a useful tool for both retrospective and prospective studies of disease course as well as for monitoring treatment response in clinical trials for retinal degenerative diseases.

Subretinal abscess causing restricted diffusion on magnetic resonance imaging.

Background: Restricted diffusion of water molecules on diffusion-weighted magnetic resonance imaging most commonly associated with acute stroke, has also been described in brain abscess. It has been reported in only one case of sub-retinal abscess. Methods: Review of two cases. Results: Two cases of visual loss from subretinal abscess had restricted diffusion in the region of the abscess. In the first case, DWI revealed restricted diffusion in a white mass visible in the posterior retina. In the second case, restricted diffusion was present in an anterior retinal mass invisible by ophthalmoscopy and ultrasound. In combination of restricted diffusion in the cerebrum consistent with septic emboli, these imaging abnormalities allowed earlier treatment that either preserved vision or prevented enucleation.

A Review of Visual and Oculomotor Outcomes in Children With Posterior Fossa Tumors

Tumors of the posterior fossa represent the most common solid malignancy of childhood and can affect the visual system in several ways. This article outlines the relevant visual anatomy affected by these tumors and reviews the visual and oculomotor outcomes associated with the following 3 most common tumor types-medulloblastoma, juvenile pilocytic astrocytoma, and ependymoma. The available data suggest that the rate of permanent vision loss is low (5.9%-8.3%), with patients having juvenile pilocytic astrocytoma demonstrating the best outcomes. The rate of long-term strabismus (25%-29.1%) and nystagmus (12.5%-18%) is higher and associated with significant morbidity.

Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION): A Review and Update on Animal Models

ABSTRACT Non-arteritic anterior ischemic optic neuropathy (NAION) is a relatively common optic neuropathy in adults over the age of 50, typically causing sudden, painless, unilateral vision loss and always resulting in swelling of the optic nerve head. Though several anatomic and vascular risk factors have been identified, much remains unknown about its pathophysiology and there is no proven treatment. This article reviews the risk factors, clinical presentation, and therapies that have been investigated for NAION. In addition, we provide an update from recent rodent and primate models, which offer new insight into the pathophysiology of this disease and provide a platform for treatment trials.

Telemedicine for corneal disease in rural Nepal

We evaluated the diagnostic accuracy of slit-lamp photographs interpreted by telemedicine compared to a conventional clinical examination. A convenience sample of 21 patients with anterior segment disease was enrolled at the Lumbini Eye Institute (LEI) in Bhairahawa, Nepal. An ophthalmologist at the LEI examined each patient and assigned a diagnosis and follow-up interval; this represented the gold standard. An ophthalmic technician also obtained anterior segment photographs of each patient. Slit-lamp photographs and clinical histories were then uploaded to a server for access by three separate readers. These readers, one in Nepal and two in the US, provided a diagnosis and follow-up interval independently. The diagnostic agreement between the examiner and all readers was good (kappa = 0.75, P < 0.0001). The agreement regarding follow-up interval between the examiner and all readers was fair, with a kappa coefficient of 0.32 (P < 0.0001). However, the agreement was high when comparing the examiner with the reviewer in Nepal (kappa = 0.90) and was moderate when comparing the two US-based readers with each other (kappa = 0.45). In general, the ophthalmologists in Nepal recommended more rapid follow-up than their US-based counterparts. Our results suggest that the transmission of slit-lamp photographs from satellite clinics and eye health screening camps to the LEI and elsewhere for review and triage is an effective means of identifying anterior segment pathology.

Uveitis–glaucoma–hyphema syndrome secondary to a Soemmerring ring

We report the case of a patient who developed the uveitis-glaucoma-hyphema (UGH) syndrome secondary to extensive fibrosis (Soemmerring ring) around the haptics of the single-piece intraocular lens (IOL) in the capsular bag. The development of significant capsule fibrosis caused the IOL to tilt out of the iris plane, leading to haptic-iris and haptic-ciliary body chafing. The mechanisms described should prompt clinicians to consider the UGH syndrome even in the setting of a single-piece IOL properly placed in the capsular bag. Anterior segment imaging with ultrasound biomicroscopy can be used to evaluate the position of the IOL haptics in suspected cases.

Cervical Arteriovenous Malformation Causing Horner's Syndrome

Originally received: October 3, 2016. Final revision: November 3, 2016. Accepted: November 8, 2016. Available online: December 23, 2016. Manuscript no. 2016-482. 1 Department of Twin Research & Genetic Epidemiology, King’s College London, St. Thomas’ Hospital, Waterloo, London, United Kingdom. 2 Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands. 3 Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands. 4 Department of Ophthalmology, King’s College London, St. Thomas’ Hospital, Waterloo, London, United Kingdom. Financial Disclosure(s): The author(s) have made the following disclosure(s): C.J.H.: Grants e pending from Alcon. Supported by a grant from the Gratama Stichting, University of Groningen. The funding organization had no role in the design or conduct of this research.

Radiation optic neuropathy and retinopathy with low dose (20 Gy) radiation treatment

Purpose To report a case of optic neuropathy and retinopathy from a dose of radiation traditionally thought to be safe to the visual system and discuss strategies for preventing vision loss when using radiation to treat intraocular tumors. Observations A 44-year-old woman presented with new, painless vision loss in the left eye eighteen months after receiving proton beam radiotherapy (20 Gy dose delivered in two 10 Gy fractions) for a uveal metastasis of lung cancer. The dilated funduscopic examination revealed optic disc swelling and retinal hemorrhages and an MRI of the brain and orbits demonstrated enhancement of the left optic nerve head, findings consistent with radiation optic neuropathy (RON) and retinopathy. Risk factors for developing RON included coincident use of oral chemotherapy and relatively large fractionated doses of radiation. Conclusions and importance Though cumulative radiation doses to the anterior visual pathway of less than 50 Gy are traditionally felt to be safe, it is important to consider not just the total exposure but also the size of individual fractions. The single-dose threshold for RON in proton beam treatment has yet to be defined. Our case suggests that fractions of less than 10 Gy should be delivered to minimize the risk of optic nerve injury.