Anja M. Palmowski-Wolfe

ISCEV standard for clinical multifocal electroretinography (mfERG) (2011 edition)

The clinical multifocal electroretinogram (mfERG) is an electrophysiological test of local retinal function. With this technique, many local ERG responses are recorded quasi-simultaneously from the cone-driven retina under light-adapted conditions. This document, from the International Society for Clinical Electrophysiology of Vision (ISCEV: www.iscev.org), replaces the ISCEV guidelines for the mfERG published in 2007. Standards for performance of the basic clinical mfERG test with a stimulus array of 61 or 103 hexagons, as well as for reporting the results, are specified.

ISCEV guidelines for clinical multifocal electroretinography (2007 edition).

The clinical multifocal electroretinogram (mfERG) is an electrophysiological test of local retinal function. With this technique, many local ERG responses, typically 61 or 103, are recorded from the cone-driven retina under light-adapted conditions. This document specifies guidelines for performance of the test. It also provides detailed guidance on technical and practical issues, as well as on reporting test results. The main objective of the guidelines is to promote consistent quality of mfERG testing and reporting within and among centers. These 2007 guidelines, from the International Society for Clinical Electrophysiology of Vision (ISCEV: http://www.iscev.org), replace the ISCEV guidelines for the mfERG published in 2003.

Antiphospholipid Antibodies in Ocular Arterial and Venous Occlusive Disease

Purpose: It was the aim of this study to evaluate antiphospholipid antibodies (APA), i.e. lupus anticoagulants (LA) and anticardiolipin (ACA) IgG and IgM, in ophthalmic occlusive disease. Methods: Over a 3.5-year period, APA were evaluated in 368 patients. Results: Eighty-six patients (23.4%), compared to 5% in the general population, tested positive for APA. APA did not differ significantly between patients with venous (20.6%) or arterial (25.5%) occlusive disease. This included 93 patients with central retinal vein occlusion (18% APA positive), 67 with retinal branch vein occlusion (24% APA positive), 41 with central retinal artery occlusion (22% APA positive), 53 with retinal branch artery occlusion (32% APA positive), 71 with anterior ischemic optic neuropathy (23% APA positive), 12 with posterior ischemic optic neuropathy (33% APA positive) and 31 patients with amaurosis fugax (23% APA positive). Excluding patients with accepted main risk factors, APA were positive in 15.3% of 85 patients. Conclusion: The high APA prevalence confirms its relevance in ocular occlusive disorders.

LED-generated Multifocal ERG On- and Off-responses in Complete Congenital Stationary Night Blindness – A Case Report

We report on the application of a light emitting diode (LED) screen to elicit multifocal ERG on- and off-responses in a patient presenting with the complete type of congenital stationary night blindness (cCSNB): A 63-years old woman was diagnosed with cCSNB by means of standard ERG procedures and dark adaptometry. To confirm this diagnosis and to investigate topographical differences of on- and off-responses a multifocal approach employing long-duration stimuli was added. Results of mfERG-testing were averaged in three groups (a central area of 7.5°, a ring area of 7.5–21.9° and a peripheral ring of 21.9–31.1°). When compared to normal controls (n = 4) on-responses (P1-amplitudes) were severely reduced symmetrically at all eccentricities, while off-responses showed no reduction resulting in an increased off/on-ratio. Furthermore on-latencies of P1 were delayed symmetrically at all eccentricities, whereas off-latencies were normal. To our knowledge this is the first report of multifocal on- and off-responses in a CSNB-patient. Stimulus-generation with a LED-screen provides the advantage of a stable luminance during the long-duration on-phase.

Near-real time oculodynamic MRI: a feasibility study for evaluation of diplopia in comparison with clinical testing

AbstractObjectiveTo demonstrate feasibility of near-real-time oculodynamic magnetic resonance imaging (od-MRI) in depicting extraocular muscles and correlate quantitatively the motion degree in comparison with clinical testing in patients with diplopia.MethodsIn 30 od-MRIs eye movements were tracked in the horizontal and sagittal plane using a a TrueFISP sequence with high temporal resolution. Three physicians graded the visibility of extraocular muscles by a qualitative scale. In 12 cases, the maximal monocular excursions in the horizontal and vertical direction of both eyes were measured in od-MRIs and a clinical test and correlated by the Pearson test.ResultsThe medial and lateral rectus muscles were visible in the axial plane in 93% of the cases. The oblique, superior and inferior rectus muscles were overall only in 14% visible. Horizontal (p = 0,015) and vertical (p = 0,029) movements of the right eye and vertical movement of the left eye (p = 0,026) measured by od-MRI correlated positively to the clinical measurements.ConclusionsOd-MRI is a feasible technique. Visualization of the horizontal/vertical rectus muscles is better than for the superior/inferior oblique muscle. Od-MRI correlates well with clinical testing and may reproduce the extent of eye bulb motility and extraocular muscle structural or functional deteriorations. Key Points• Oculodynamic MRI technique helps clinicians to assess eye bulb motility disorders• MRI evaluation of eye movement provides functional information in cases of diplopia• Oculodynamic MRI reproduces excursion of extraocular muscles with good correlation with clinical testing• Dynamic MRI sequence supplements static orbital protocol for evaluation of motility disorders

Characterization of excitation-contraction coupling components in human extraocular muscles.

Excitation-contraction coupling (ECC) is the physiological mechanism whereby an electrical signal detected by the dihydropyridine receptor, is converted into an increase in [Ca2+], via activation of ryanodine receptors (RyRs). Mutations in RYR1, the gene encoding RyR1, are the underlying cause of various congenital myopathies including central core disease, multiminicore disease (MmD), some forms of centronuclear myopathy (CNM) and congenital fibre-type disproportion. Interestingly, patients with recessive, but not dominant, RYR1 mutations show a significant reduction in RyR protein in muscle biopsies as well as ophthalmoplegia. This specific involvement of the extraocular muscles (EOMs) indicates that this group of muscles may express different amounts of proteins involved in ECC compared with limb muscles. In the present paper, we report that this is indeed the case; in particular the transcripts encoding RyR3, cardiac calsequestrin (CSQ2) and the α1 subunit of the cardiac dihydropyridine receptor are up-regulated by at least 100-fold, whereas excitation-coupled Ca2+ entry is 3-fold higher. These findings support the hypothesis that EOMs have a unique mode of calcium handling.

Globe restriction in a severely myopic patient visualized through oculodynamic magnetic resonance imaging (od-MRI)

Different mechanisms have been hypothesized as contributing to abduction deficit in high myopia: the size of the eye within the orbit, tightness of the medial rectus muscles, decompensation of longstanding esotropia, and inferior displacement of the lateral rectus muscle. Using oculodynamic magnetic resonance imaging, enhanced by computer-aided visualization, we demonstrate globe restriction by the medial orbital wall on abduction in a patient with high myopia.

Comparison of Two Different OCT Systems: Retina Layer Segmentation and Impact on Structure-Function Analysis in Glaucoma

Purpose. To compare two different spectral-domain optical coherence tomography (OCT) systems in regard to full macular thickness (MT) and ganglion cell layer-inner plexiform layer (GCIPL) measures and in regard to structure-function correlation when compared to standard automated perimetry (SAP). Methods. Seventeen primary open angle glaucoma patients and 16 controls (one eye per subject) were enrolled. MT and GCIPL thicknesses were measured by Cirrus and Spectralis OCTs. Octopus Perimeter 101 (G2 protocol) reports sensitivity in mean defect (dB). Differences between measurements were assessed with Students t-test and Bland Altman. Diagnostic performance was also compared between each parameter calculating the areas under the operator receiver (ROC). Linear models were used to investigate structure-function association between OCT and SAP. Results. Disagreement between OCTs in both MT and GCIPL values was significant. Spectralis values were thicker than Cirrus. Average difference between OCTs was 21.64 μm (SD 4.5) for MT and 9.8 μm (SD 5.4) for GCIPL (p < 0.001). Patients differed significantly from controls in both OCTs, in both measurements. MT and GCIPL were negatively associated with MD (p < 0.001). Conclusions. Although OCT values were not interchangeable, both machines differentiated patients from controls with statistical significance. Structure-function analysis results were comparable, when either OCT was compared to SAP.

A Comparison between the Pulsed Rising Amplitude Perimetry and the Normal Staircase Strategy in Standard Automated Perimetry

Background and scope: Pulsed rising amplitude perimetry (pulsed RAMP) is an improved strategy for automated static perimetry, developed to save examination time without accuracy loss. The aim of this study was to identify characteristic differences between the normal strategy (NS) and the pulsed RAMP strategy in standard automated perimetry, in order to evaluate the potential of the pulsed RAMP for threshold estimation. Methods: Visual fields from 33 glaucoma patients, 11 controls and 4 patients with other pathology were statistically analysed. A G pattern test using the pulsed RAMP and the NS were performed in randomised order. The MD (mean defect), the sLV (square root of loss variance), the test duration and the point-wise accuracy, related to a calculated reference pre- and post-study visual fields of each patient, were evaluated. Results: The mean examination time was 8.34 min (SD 2.02) for the pulsed RAMP, compared to 13.37 min (SD 2.67) for the NS. The Bland-Altman correlation plot for the MDs showed a trend (p=0.0018) towards higher MDs in the pulsed RAMP compared to the NS. The sLV of the pulsed RAMP was on average 1.49 dB higher than the sLV of the NS. The absolute mean local deviations, evaluated with the pulsed RAMP (r=0.38), deviated more from the references than those obtained with the NS. Conclusion: The pulsed RAMP strategy was faster than the NS, but took longer than other established fast strategies like the SITA, TOP and Dynamic. The gain in time, compared to the NS, was paired with reduced local accuracy.

Botulinum Toxin for the Treatment of Cyclic Strabismus in Children: Three Case Reports

Cyclic strabismus is a rare disease of unknown origin. If untreated, it leads to manifest strabismus with the risk of amblyopia in children. Treatment is generally surgical. Here we report on three children in whom cyclic esotropia was successfully treated with one bimedial injection of 5 IU Botox®. All patients remained orthotropic with good stereo functions at the last follow-ups at 16, 11, and 8 months. Botulinum toxin offered a minimally invasive treatment option in these patients.