ISCEV extended protocol for the dark-adapted red flash ERG

Abstract

The International Society for Clinical Electrophysiology of Vision (ISCEV) standard for full-field electroretinography (ERG) describes a minimum procedure, but encourages more extensive testing. This ISCEV extended protocol describes an extension to the ERG standard, namely the dark-adapted (DA) red flash ERG. The DA red flash ERG can be incorporated conveniently within the ISCEV standard ERG protocol after a minimum of 20-min DA and recorded after the DA 0.01 ERG to a flash strength of 0.3 phot cd s m−2, eliciting a waveform with two positive peaks in healthy individuals. The first positive component is the cone-mediated x-wave with a peak at 30–50 ms; the second is a rod-mediated b-wave with a peak time of approximately 100 ms. Shorter DA times may be desirable to shorten the recording time or to alter the prominence of the early cone-mediated x-wave relative to the rod-mediated b-wave. The DA red flash ERG is used to aid the diagnosis of achromatopsia (rod monochromacy), cone dystrophy and other forms of cone system dysfunction, including “Bradyopsia” (RGS9/R9AP-retinopathy), when the DA red flash ERG x-wave is preserved in the absence of ISCEV standard LA ERGs. The DA red flash ERG can also help determine the origin of residual DA ERGs in cases of severe rod dysfunction, for example in disorders such as vitamin A deficiency, fundus albipunctatus (RDH5-retinopathy), Oguchi disease (SAG- or GRK1-retinopathy) and some rod-cone dystrophies. To shorter DA periods, the x-wave may be elicited without the following rod b-wave, shown to be helpful in abbreviated protocols for children.

VEP estimation of visual acuity: a systematic review

“…The International Society for Clinical Electrophysiology of Vision (ISCEV) writes and updates standards [66,[214][215][216][217], guidelines [218,219] and extended protocols [220][221][222][223][224] with the aim of reducing inter-laboratory test variability, one aspect of quality improvement which reduces inherent uncertainty and enhances patient safety. The ISCEV standards, guidelines and extended protocols address quality of the test process, provide some guidance on appropriate clinical use, and address some aspects of interpretation and communication of test results.…”

Isolated rod dysfunction associated with a novel genotype of CNGB1

“…Full field and pattern electroretinography (ERG; PERG) were performed, using extended protocols that incorporated those of the International Society for Clinical Electrophysiology of Vision 9, 10, 11. The results are shown in Fig.…”

The Ophthalmic Complications of Bariatric Surgery: The Role of Vitamin A Deficiency

“…Vitamin A deficiency is associated with severe rod photoreceptor dysfunction, which is known to be reversible if substitution is initiated early in the clinical course [9]. Cases of irreversible blindness are known to occur as a result of chronic vitamin A deficiency [10].…”

“…Determination of retinol levels can be a crucial diagnostic step for patients with appropriate findings and risk factors for malabsorption. Retinol levels below 0.75 µmol/L are consistent with relevant deficiency [9]. If recognized early and the vitamin A levels are restored promptly, complications of acquired vitamin A deficiency are said to be fully reversible.…”