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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.

Visual electrophysiology is a valuable tool for evaluating the visual system in various systemic syndromes. This review highlights its clinical application in a selection of syndromes associated with hearing loss, mitochondrial dysfunction, obesity, and other multisystem disorders. Techniques such as full-field electroretinography (ffERG), multifocal electroretinography (mfERG), pattern electroretinography (PERG), visual evoked potentials (VEP), and electrooculography (EOG) offer insights into retinal and optic nerve function, often detecting abnormalities before clinical symptoms manifest. In hearing loss syndromes like Refsum disease, Usher syndrome (USH), and Wolfram syndrome (WS), electrophysiology facilitates the detection of early retinal changes that precede the onset of visual symptoms. For mitochondrial disorders such as maternally-inherited diabetes and deafness (MIDD), Kearns–Sayre syndrome (KSS), and neuropathy, ataxia, and retinitis pigmentosa (NARP) syndrome, these tests can be useful in characterizing retinal degeneration and optic neuropathy. In obesity syndromes, including Bardet-Biedl syndrome (BBS), Alström syndrome, and Cohen syndrome, progressive retinal degeneration is a hallmark feature. Electrophysiological techniques aid in pinpointing retinal dysfunction and tracking disease progression. Other syndromes, such as Alagille syndrome (AGS), abetalipoproteinemia (ABL), Cockayne syndrome (CS), Joubert syndrome (JS), mucopolysaccharidosis (MPS), Neuronal ceroid lipofuscinoses (NCLs), and Senior–Løken syndrome (SLS), exhibit significant ocular involvement that can be evaluated using these methods. This review underscores the role of visual electrophysiology in diagnosing and monitoring visual system abnormalities across a range of syndromes, potentially offering valuable insights for early diagnosis, monitoring of progression, and management.

Visual electrophysiology measurements are important for ophthalmic diagnostic testing. Electrodes with combined optical transparency and softness are highly desirable, and sometimes indispensable for many ocular electrophysiology measurements. Here we report the fabrication of soft graphene contact lens electrodes (GRACEs) with broad-spectrum optical transparency, and their application in conformal, full-cornea recording of electroretinography (ERG) from cynomolgus monkeys. The GRACEs give higher signal amplitude than conventional ERG electrodes in recordings of various full-field ERG responses. High-quality topographic mapping of multifocal ERG under simultaneous fundus monitoring is realized. A conformal and tight interface between the GRACEs and cornea is revealed. Neither corneal irritation nor abnormal behavior of the animals is observed after ERG measurements with GRACEs. Furthermore, spatially resolved ERG recordings on rabbits with graphene multi-electrode array reveal a stronger signal at the central cornea than the periphery. These results demonstrate the unique capabilities of the graphene-based electrodes for in vivo visual electrophysiology studies. The electrical response of the eye to optical stimulus is important in disease diagnosis but current electrodes used have limitations. Here, the authors report on the development of soft transparent graphene-based contact lens electrodes for electroretinogram recording and test the device in vivo.

This document, from the International Society for Clinical Electrophysiology of Vision (ISCEV), presents an updated and revised ISCEV Standard for full-field clinical electroretinography (ffERG or simply ERG). The parameters for Standard flash stimuli have been revised to accommodate a variety of light sources including gas discharge lamps and light emitting diodes. This ISCEV Standard for clinical ERGs specifies six responses based on the adaptation state of the eye and the flash strength: (1) Dark-adapted 0.01 ERG (rod ERG); (2) Dark-adapted 3 ERG (combined rod-cone standard flash ERG); (3) Dark-adapted 3 oscillatory potentials; (4) Dark-adapted 10 ERG (strong flash ERG); (5) Light-adapted 3 ERG (standard flash “cone” ERG); and (6) Light-adapted 30 Hz flicker ERG. ISCEV encourages the use of additional ERG protocols for testing beyond this minimum standard for clinical ERGs.

This document, from the International Society for Clinical Electrophysiology of Vision (ISCEV), presents an updated and revised ISCEV Standard for clinical electroretinography (ERG). The parameters for flash stimulation and background adaptation have been tightened, and responses renamed to indicate the flash strength (in cd·s·m −2 ). The ISCEV Standard specifies five responses: (1) Dark-adapted 0.01 ERG (rod response); (2) Dark-adapted 3.0 ERG (combined rod–cone response); (3) Dark-adapted 3.0 oscillatory potentials; (4) Light-adapted 3.0 ERG (cone response); (5) Light-adapted 3.0 flicker (30 Hz flicker). An additional Dark-adapted 10.0 ERG or Dark-adapted 30.0 ERG response is recommended.

To evaluate the effectiveness of the non-mydriatic mode of the HE-2000 electroretinogram (ERG) by comparing photopic ERGs of non-mydriatic versus dilated eyes. This retrospective study included patients with grade 2 cataracts between January and July 2022. Photopic ERGs were recorded using the HE-2000 system in mydriatic eyes with a 3 cd·s/m 2 flashing stimulus and in non-mydriatic eyes using the non-mydriatic mode with a 10 cd·s/m 2 stimulus. Amplitudes and implicit times of the a-wave, b-wave, and flicker ERG were compared using the Wilcoxon signed-rank test. Correlations between these parameters were analyzed using Spearman’s rank correlation coefficient. In 54 eyes of 27 participants, the b-wave and flicker ERG amplitudes were lower in non-dilated eyes compared to dilated ones, with prolonged implicit times observed in non-dilated eyes ( p  < 0.0001). Despite these differences, both b-wave and flicker ERG amplitudes and implicit times showed strong correlations between dilated and non-dilated eyes ( p  < 0.01). However, the a-wave amplitude was more variable and less consistently measurable in non-dilated eyes. The HE-2000 system can provide clinically useful ERG recordings in non-dilated eyes, particularly for b-wave and flicker responses. Further validation under non-mydriatic conditions is required to establish its broader clinical utility.

Electroretinogram examinations serve as routine clinical procedures in ophthalmology for the diagnosis and management of many ocular diseases. However, the rigid form factor of current corneal sensors produces a mismatch with the soft, curvilinear, and exceptionally sensitive human cornea, which typically requires the use of topical anesthesia and a speculum for pain management and safety. Here we report a design of an all-printed stretchable corneal sensor built on commercially-available disposable soft contact lenses that can intimately and non-invasively interface with the corneal surface of human eyes. The corneal sensor is integrated with soft contact lenses via an electrochemical anchoring mechanism in a seamless manner that ensures its mechanical and chemical reliability. Thus, the resulting device enables the high-fidelity recording of full-field electroretinogram signals in human eyes without the need of topical anesthesia or a speculum. The device, superior to clinical standards in terms of signal quality and comfortability, is expected to address unmet clinical needs in the field of ocular electrodiagnosis. Though smart contact lenses are an attractive technology for recording electroretinogram signals, existing approaches suffer from poor mechanical reliability, chemical stability and wettability. Here, the authors report an all-printed stretchable corneal sensor built on commercial soft contact lenses.

The principal aim of this investigation was to assess the utility of a novel DR score for the early detection of diabetic polyneuropathy (DPN). This score, currently integrated into the RETeval™ electroretinogram (ERG) system, is derived from parameters such as ERG wave characteristics, patient age, and pupillary response. Traditional nerve conduction studies (NCS), though valuable, have notable limitations, including the necessity for costly equipment and specialized personnel. Consequently, it was postulated that the DR score-initially devised for predicting diabetic retinopathy-might serve as a practical alternative for diagnosing DPN. This study sought to test the hypothesis that the DR score could offer a reliable means of both diagnosing DPN and estimating its severity. The study retrospectively analyzed 82 diabetic patients admitted to Aichi Medical University Hospital between November 2016 and January 2019. ERG was performed using the RETeval™ device, and NCS was conducted to classify DPN stages according to the Baba's Differentiation Classification (BDC) system. Multiple regression analysis and receiver operating characteristics (ROC) analysis were employed to assess the relationship between the DR score and DPN stages. Among 82 participants, 24.4% (n = 20) had no DPN (stage 0), and 75.6% (n = 62) had stage 1 or higher DPN. The DR score was significantly correlated with various clinical parameters, including nerve conduction velocities and the severity of DPN as classified by BDC stages. The regression model showed that both the DR score and age were significant predictors of DPN severity. The ROC analysis demonstrated that the DR score had a moderate ability to discriminate between no DPN and stage 1 or more of DPN, with an area under the ROC curve of 0.738. In conclusion, this study involving 82 patients suggests that the DR score may be a valuable tool for the early detection and staging of DPN, potentially offering a more accessible and cost-effective alternative to traditional NCS, with significant implications for improving diabetic care.

Myopia is the commonest visual impairment. Several genetic loci confer risk, but mechanisms by which they do this are unknown. Retinal signals drive eye growth, and myopia usually results from an excessively long eye. The common variant most strongly associated with myopia is near the GJD2 gene, encoding connexin-36, which forms retinal gap junctions. Light-evoked responses of retinal neurons can be recorded noninvasively as the electroretinogram (ERG). We analyzed these responses from 186 adult twin volunteers who had been genotyped at this locus. Participants underwent detailed ERG recordings incorporating international standard stimuli as well as experimental protocols aiming to separate dark-adapted rod- and cone-driven responses. A mixed linear model was used to explore association between allelic dosage at the locus and international standard ERG parameters after adjustment for age, sex, and family structure. Significant associations were found for parameters of light-adapted, but not dark-adapted, responses. Further investigation of isolated rod- and cone-driven ERGs confirmed associations with cone-driven, but not rod-driven, a-wave amplitudes. Comparison with responses to similar experimental stimuli from a patient with a prior central retinal artery occlusion, and from two patients with selective loss of ON-bipolar cell signals, was consistent with the associated parameters being derived from signals from cone-driven OFF-bipolar cells. Analysis of single-cell transcriptome data revealed strongest GJD2 expression in cone photoreceptors; bipolar cell expression appeared strongest in OFF-bipolar cells and weakest in rod-driven ON-bipolar cells. Our findings support a potential role for altered signaling in cone-driven OFF pathways in myopia development.