Discover the abridged ERG for children.
Full-field ERG is a pivotal diagnostic tool for detecting generalized retinal dysfunction and identifying functional abnormalities within the retina. The International Society for Clinical Electrophysiology of Vision (ISCEV) ERG sets the gold standard for this testing method by defining stimulus and recording parameters. These parameters are designed to trigger responses from retinal systems to identify the locus and extent of retinal dysfunction. As we enter the genomic era of medicine, thorough cataloging of retinal phenotype and natural history, as well as early diagnosis of retinal disease, become essential for gaining access to treatment trials.
While ISCEV-ERG is the gold standard, it acknowledges the challenges of performing it on ‘non-compliant children between 2 and 5yrs.’ This test requires that a child dark-adapt for 10 to 20 minutes while wearing electrodes then remain in a fixed, forward-facing position for multiple flash exposures. For this reason, the ISCEV-ERG is often either done under anesthesia or omitted for this age group entirely.
In the early 1990s, Great Ormond Street Hospital (GOSH) developed an alternative protocol for ERG testing in children, which has been used by many centers internationally for many years. This protocol requires only 5-10 minutes test time, with natural pupils, minimal dark adaptation, skin electrodes and handheld flash stimulation, for ability to test in alert children of all ages. The GOSH-ERG has been validated against the ISCEV-ERG and proven to yield excellent diagnostic accuracy in comparison.
The GOSH-ERG stands as an effective alternative for screening, diagnosis, and monitoring of retinal disease in children who find it challenging to undergo the standard ISCEV-ERG. In clinical practice, a ‘systems analysis’ approach is often used to comprehensively examine retinal dysfunction. This approach categorizes retinal abnormalities into rod system, rod photoreceptor, cone system, and those affecting the inner-retina which are reflected as individual components of the ERG waveforms. When compared to the traditional ISCEV-ERG, the GOSH-ERG demonstrates excellent agreement in terms of both sensitivity and specificity, making it a reliable screening tool for children who are less able to comply with conventional testing methods. This includes the recognition of pathogneumonic ERG features as one may expect to see in the ISCEV standard ERG.
References:
Kriss A. Skin ERGs: their effectiveness in paediatric visual assessment, confounding factors, and comparison with ERGs recorded using various types of corneal electrode. Int J Psychophysiol. 1994 May;16(2-3):137-46. doi: 10.1016/0167-8760(89)90040-8. PMID: 8089032.
Kriss A, Jeffrey B, Taylor D. The electroretinogram in infants and young children. J Clin Neurophysiol. 1992 Jul;9(3):373-93. doi: 10.1097/00004691-199207010-00005. PMID: 1517405.
Kriss A, Russell-Eggitt I. Electrophysiological assessment of visual pathway function in infants. Eye (Lond). 1992;6 ( Pt 2):145-53. doi: 10.1038/eye.1992.30. PMID: 1624036.
Marmoy OR, Moinuddin M, Thompson DA. An alternative electrophysiology protocol for children: a study of diagnostic agreement and accuracy relative to ISCEV standard electroretinograms. Acta Ophthalmologica (2022) 100: 322-330.