Michael F. Marmor

Standard for clinical electroretinography (2004 update)

(for the International Society for Clinical Electrophysiology of Vision) (for the International Society for Clinical Electrophysiology of Vision)

Revised Recommendations on Screening for Chloroquine and Hydroxychloroquine Retinopathy

BACKGROUND The American Academy of Ophthalmology recommendations for screening of chloroquine (CQ) and hydroxychloroquine (HCQ) retinopathy were published in 2002, but improved screening tools and new knowledge about the prevalence of toxicity have appeared in the ensuing years. No treatment exists as yet for this disorder, so it is imperative that patients and their physicians be aware of the best practices for minimizing toxic damage. RISK OF TOXICITY New data have shown that the risk of toxicity increases sharply toward 1% after 5 to 7 years of use, or a cumulative dose of 1000 g, of HCQ. The risk increases further with continued use of the drug. DOSAGE The prior recommendation emphasized dosing by weight. However, most patients are routinely given 400 mg of HCQ daily (or 250 mg CQ). This dose is now considered acceptable, except for individuals of short stature, for whom the dose should be determined on the basis of ideal body weight to avoid overdosage. SCREENING SCHEDULE A baseline examination is advised for patients starting these drugs to serve as a reference point and to rule out maculopathy, which might be a contraindication to their use. Annual screening should begin after 5 years (or sooner if there are unusual risk factors). SCREENING TESTS Newer objective tests, such as multifocal electroretinogram (mfERG), spectral domain optical coherence tomography (SD-OCT), and fundus autofluorescence (FAF), can be more sensitive than visual fields. It is now recommended that along with 10-2 automated fields, at least one of these procedures be used for routine screening where available. When fields are performed independently, even the most subtle 10-2 field changes should be taken seriously and are an indication for evaluation by objective testing. Because mfERG testing is an objective test that evaluates function, it may be used in place of visual fields. Amsler grid testing is no longer recommended. Fundus examinations are advised for documentation, but visible bulls-eye maculopathy is a late change, and the goal of screening is to recognize toxicity at an earlier stage. COUNSELING Patients should be aware of the risk of toxicity and the rationale for screening (to detect early changes and minimize visual loss, not necessarily to prevent it). The drugs should be stopped if possible when toxicity is recognized or strongly suspected, but this is a decision to be made in conjunction with patients and their medical physicians.

National Case-Control Study of Kaposi's Sarcoma and Pneumocystis carinii Pneumonia in Homosexual Men: Part 1, Epidemiologic Results

To identify risk factors for the occurrence of Kaposis sarcoma and Pneumocystis carinii pneumonia in homosexual men, we conducted a case-control study in New York City, San Francisco, Los Angeles, and Atlanta. Fifty patients (cases) (39 with Kaposis sarcoma, 8 with pneumocystis pneumonia, and 3 with both) and 120 matched homosexual male controls (from sexually transmitted disease clinics and private medical practices) participated in the study. The variable most strongly associated with illness was a larger number of male sex partners per year (median, 61 for patients; 27 and 25 for clinic and private practice controls, respectively). Compared with controls, cases were also more likely to have been exposed to feces during sex, have had syphilis and non-B hepatitis, have been treated for enteric parasites, and have used various illicit substances. Certain aspects of a lifestyle shared by a subgroup of the male homosexual population are associated with an increased risk of Kaposis sarcoma and pneumocystis pneumonia.

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

Guidelines for basic multifocal electroretinography (mfERG)

Michael F. Marmor1, Donald C. Hood2, David Keating3, Mitsuhiro Kondo4, Mathias W. Seeliger5 & Yozo Miyake4 (for the International Society for Clinical Electrophysiology of Vision) 1Department of Ophthalmology, Stanford University School of Medicine, Stanford, California, USA; 2Department of Psychology, Columbia University, New York, New York, USA; 3Department of Ophthalmology, Gartnavel General Hospital, Glasgow, UK; 4Department of Ophthalmology, Nagoya University School of Medicine, Nagoya, Japan; 5Department II, University Eye Hospital, Tubingen, Germany

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.

Mechanisms of fluid accumulation in retinal edema

This paper reviews the anatomic and physiologic conditions which predispose to fluid accumulation within the retina. Retinal edema has its inception in disease that causes a breakdown of the blood-retinal barrier in retinal capillaries and/or the retinal pigment epithelium (RPE). Edema develops not only because protein and fluid enter the extracellular space, but because the external limiting membrane and the convoluted extracellular pathway within the retina limit the clearance of albumin and other large osmotically-active molecules. These molecules bind water to cause edema. Recognition of edema clinically is complicated by the facts that angiographic markers (fluorescein and ICG) do not match albumin in size, and that clinical leakage does not always correlate closely with tissue swelling or functional loss. Active water transport across the RPE is efficient at removing subretinal water, but the flow resistance of the retina limits RPE access to the water of retinal edema. Consideration of the pathophysiology of retinal edema may aid in the development of better strategies for managing retinal edema.

Standard for pattern electroretinography. International Society for Clinical Electrophysiology of Vision.

The pattern electroretinogram (PERG) is a retinal response evoked by viewing an alternating checkerboard or grating. It receives clinical and research attention because it can provide information about inner retinal cells and the macula. However, clinicians may have trouble choosing between different techniques for recording the PERG that have been described in the literature. The International Society for Clinical Electrophysiology of Vision has prepared a standard for a basic PERG recording procedure to aid new users in obtaining reliable responses and to encourage more uniformity among existing users.

Rates and predictors of hydroxychloroquine retinal toxicity in patients with rheumatoid arthritis and systemic lupus erythematosus.

Hydroxychloroquine (HCQ) retinopathy is of concern because of the potential seriousness of visual loss and the medicolegal consequences of failure to detect toxicity. However, there have been limited demographic data on which to base recommendations for screening. We have studied the largest unselected series of patients to date to evaluate the risk of toxicity and the relevance of purported risk factors.

New hypotheses on the pathogenesis and treatment of serous retinal detachment.

Recent experimental work has shown that, under normal conditions, most subretinal fluid is absorbed rapidly by active transport across the retinal pigment epithelium (RPE). However, in the presence of damage to the RPE blood-retinal barrier, subretinal fluid is rapidly cleared by passive forces. Thus, it is apparent that RPE defects do not by themselves cause serous retinal detachment. A hypothesis is presented that some serous detachments occur because normal metabolic transport systems of the RPE have been damaged, while the blood-retinal barrier remains intact to prevent passive drainage of the subretinal space. Under these conditions, a focal RPE “leak” can overload the system so that the serous fluid accumulates and persists. Photocoagulation of a leaking point can facilitate resolution of the fluid, but as long as the underlying metabolic dysfunction of the RPE persists, recurrence is possible. Some forms of serous detachment may thus be viewed as diffuse rather than focal ocular disorders in which the transport capability of the RPE has been damaged; such damage can result from systemic pathology such as adrenergic stress (e.g., central serous chorioretinopathy) or vascular disease (e.g., hypertension).