Mitchell Brigell

ISCEV standard for clinical pattern electroretinography—2007 update

The pattern electroretinogram (PERG) is a retinal response evoked by viewing a temporally alternating pattern, usually a black and white checkerboard or grating. The PERG is important in clinical and research applications because it provides information both about retinal ganglion cell function and, because the stimulus is customarily viewed with central fixation, the function of the macula. The PERG can therefore facilitate interpretation of an abnormal pattern VEP by revealing the retinal responses to a similar stimulus to that used for the VEP. However, practitioners may have difficulty choosing between the different techniques for recording the PERG that have been described in the literature. The International Society for Clinical Electrophysiology of Vision published a standard for clinical PERG recording in 2000 to assist practitioners in obtaining good quality reliable responses and to facilitate inter-laboratory communication and comparison. This document is the scheduled revision of that standard.

Visual evoked potentials standard (2004)

IntroductionThisdocumentpresentsthecurrent(2004)standardfor the visual evoked potential (VEP). The VEPisanevokedelectrophysiologicalpotentialthatcanbeextracted,usingsignalaveraging,fromtheelectro-encephalographicactivityrecordedatthescalp.TheVEPcanprovideimportantdiagnosticinformationregardingthefunctionalintegrityofthevisualsystem.The current standard presents basic responseselicited by three commonly used stimulus condi-tionsusingasingle,midlinerecordingchannelwithanoccipital,activeelectrode.Becausechiasmalandretrochiasmaldiseasesmaybemissedusingasinglechannel,threechannelsusingthemidlineandtwolateralactiveelectrodesaresuggestedwhenonegoesbeyondthestandardandtestspatientsforchiasmalandretrochiasmaldysfunction.Patternreversalisthepreferredtechniqueformostclinical purposes. The results of pattern reversalstimuli are less variable in waveform and timingthantheresultselicitedbyotherstimuli.Thepatternonset/offsettechniquecanbeusefulinthedetectionofmalingeringandinpatientswithnystagmus,andtheflashVEPisparticularlyusefulwhenopticalfactorsorpoorcooperationmaketheuseofpatternstimu-lationinappropriate.Theintentofthisstandardisthat

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.

ISCEV Standard for Clinical Electro-oculography (EOG) 2006

The Clinical Electro-oculogram (EOG) is an electrophysiological test of function of the outer retina and retinal pigment epithelium (RPE) in which the change in the electrical potential between the cornea and the ocular fundus is recorded during successive periods of dark and light adaptation. This document sets out a Standard Method for performance of the test, and also gives detailed guidance on technical and practical issues, and on reporting test results. The main object of the Standard is to promote consistent quality of testing and reporting within and between centres. This 2006 Standard, from the International Society for Clinical Electrophysiology of Vision (ISCEV: www.iscev.org ), is a revision of the previous Standard published in 1993, and reviewed and re-issued in 1998.

Guidelines for calibration of stimulus and recording parameters used in clinical electrophysiology of vision

In order to perform a technically adequate clinical electrophysiological procedure it is necessary to calibrate the stimulating and recording equipment. Published standards for the electroretinogram (ERG)[1], electro-oculogram (EOG)[2], visual evoked potential (VEP)[3], and guidelines for the Pattern ERG (PERG)[4] specify stimulus and recording parameters. Yet, most commercial instruments do not provide the means for calibration of these parameters. The goal of this document is to provide guidelines for proper calibration of stimulus and recording equipment. The need for such guidelines is clear on both clinical and scientific grounds. Stimulus and amplifier characteristics have substantial effects on the peak latency and amplitude measurements that are commonly used in clinical electrophysiology. Many review articles on clinical electrophysiology emphasize the need for establishing norms for each laboratory as a function of age and gender rather than relying on published norms. However, if stimulus and recording parameters are not calibrated periodically, then these norms may actually be misleading due to changes in stimulus or recording conditions induced by aging of equipment or inadvertent change in settings.This document is divided into two major sections. The first is concerned with calibration of the visual stimulus. It begins with background technical information on the physics of light and its measurement. This is followed by protocols for measurement of the luminous intensity of flash stimuli and the mean luminance, contrast, and visual angle of pattern stimuli. The second section is concerned with calibration of electrophysiologic recording systems. It begins with a description of the characteristics of bioelectrical signals and their measurement. This is followed by protocols for measurement of electrode impedance and amplifier calibration. Although this document was prepared as guidelines for clinical electrophysiological testing, it should be noted that the techniques described are more generally applicable to studies which are dependent upon accurate measurement of luminance or electrophysiological signals.

ISCEV standard for clinical electro-oculography (2010 update)

The clinical electro-oculogram (EOG) is an electrophysiological test of the outer retina and retinal pigment epithelium (RPE) in which changes in the electrical potential across the RPE are recorded during successive periods of dark and light adaptation. This document presents the 2017 EOG Standard from the International Society for Clinical Electrophysiology of Vision (ISCEV: www.iscev.org). This standard has been reorganized and updated to include an explanation of the mechanism of the EOG, but without substantive changes to the testing protocol from the previous version published in 2011. It describes methods for recording the EOG in clinical applications and gives detailed guidance on technical requirements, practical issues and reporting of results with the main clinical measure (the Arden ratio) now termed the light peak:dark trough ratio. The standard is intended to promote consistent quality of testing and reporting within and between clinical centers.The clinical electro-oculogram (EOG) is an electrophysiological test of function of the outer retina and retinal pigment epithelium (RPE) in which changes in electrical potential across the RPE are recorded during successive periods of dark and light adaptation. This document presents the 2010 EOG Standard from the International Society for Clinical Electrophysiology of Vision (ISCEV: www.iscev.org). This revision has been reorganized and updated, but without changes to the testing protocol from the previous version published in 2006. It describes methods for recording the EOG in clinical applications and gives detailed guidance on technical requirements, practical issues, and reporting of results. It is intended to promote consistent quality of testing and reporting within and between clinical centers.

Positive spontaneous visual phenomena limited to the hemianopic field in lesions of central visual pathways

We prospectively studied 32 patients with ischemic infarction of the retrochiasmal visual pathways.Positive spontaneous visual phenomena (PSVP) in the blind hemifield were present in 13 patients (41%). The PSVP were subdivided into phosphenes, photopsias, visual hallucinations, palinopsia, and agitated delirium with hemianopia. PSVP were never associated with auditory or other sensory positive phenomena, except in patients with agitated delirium. Patients with photopsias, phosphenes, palinopsia, and visual hallucinations had similar lesions in MRI/CT, suggesting no anatomic area unique for these four phenomena. However, there was a significant difference in the severity of associated neurologic deficits between hemianopic patients with and without PSVP. Larger lesions destroying anteriorly located visual association areas precluded the development of PSVP, which may be related to release from inhibitory input of visual regions bordering the damaged area. Patients with the syndrome of agitated delirium and hemianopia had specific lesions involving the mesial aspect of the occipital lobe, the parahippocampal gyrus, and hippocampus. NEUROLOGY 1996;47: 408-417

Effects of age and hemianopic visual field loss on driving

Purpose. With the use of an interactive driving simulator, we examined the driving performance of older patients with either homonymous or quadrantic hemianopsia with primarily occipital lobe damage resulting from cerebrovascular accidents (CVAs). Methods. We compared the performance of these patients with that of a normally sighted, age-similar control group and that of a normally sighted younger group. Results. The driving performance of the patients was either worse than, or similar to, that of the older control group; all of the older individuals (both patients and normally sighted subjects) had worse performance than the younger group. Conclusions. Age-related effects combined with the effects of visual field losses in older patients with cerebrovascular accidents had a negative impact on driving skills.

Efficacy and Safety of Intravenous Secukinumab in Noninfectious Uveitis Requiring Steroid-Sparing Immunosuppressive Therapy

PURPOSE Secukinumab, a fully human anti-interleukin-17A monoclonal antibody, exhibited promising activity in a proof-of-concept study when administered in intravenous (IV) doses to patients with active, chronic, noninfectious uveitis. This study compared the efficacy and safety of different IV and subcutaneous (SC) doses of secukinumab in patients with noninfectious uveitis. DESIGN Multicenter, randomized, double-masked, dose-ranging, phase 2 clinical trial. PARTICIPANTS Thirty-seven patients with active noninfectious intermediate uveitis, posterior uveitis, or panuveitis who required corticosteroid-sparing immunosuppressive therapy. METHODS Patients were randomized to secukinumab 300 mg SC every 2 weeks for 4 doses, secukinumab 10 mg/kg IV every 2 weeks for 4 doses, or secukinumab 30 mg/kg IV every 4 weeks for 2 doses. Intravenous or SC saline was administered to maintain masking. Efficacy was assessed on day 57 (2-4 weeks after last dose). MAIN OUTCOME MEASURES Percentage of patients with treatment response, defined as (1) at least a 2-grade reduction in vitreous haze score or trace or absent vitreous haze in the study eye without an increase in corticosteroid dose and without uveitis worsening or (2) reduction in corticosteroid dosages to prespecified levels without uveitis worsening. Percentage of patients with remission, defined as anterior chamber cell and vitreous haze scores of 0 or 0.5+ in both eyes without corticosteroid therapy or uveitis worsening. RESULTS Secukinumab 30 mg/kg IV and 10 mg/kg IV, compared with the 300 mg SC dose, produced higher responder rates (72.7% and 61.5% vs. 33.3%, respectively) and remission rates (27.3% and 38.5% vs. 16.7%, respectively). Statistical and clinical superiority for the 30 mg/kg IV dose compared with the 300 mg SC dose was established in a Bayesian probability model. Other measures, including time to response onset, change in visual acuity, and change in vitreous haze score, showed numeric trends favoring IV dosing. Secukinumab, administered in IV or SC formulations, appeared safe and was well tolerated. CONCLUSIONS Intravenous secukinumab was effective and well tolerated in noninfectious uveitis requiring systemic corticosteroid-sparing immunosuppressive therapy. Greater activity with IV dosing suggests that patients may not receive sufficient drug with SC administration. High-dose IV secukinumab may be necessary to deliver secukinumab in therapeutic concentrations.