What can visual electrophysiology tell about possible visual-field defects in paediatric patients

Abstract

Recognising a potential visual-field (VF) defect in paediatric patients might be challenging, especially in children before the age of 5 years and those with developmental delay or intellectual disability. Visual electrophysiological testing is an objective and non-invasive technique for evaluation of visual function in paediatric patients, which can characterise the location of dysfunction and differentiate between disorders of the retina, optic nerve and visual pathway. The recording of electroretinography (ERG) and visual-evoked potentials (VEP) is possible from early days of life and requires no subjective input from the patient. As the origins of ERG and VEP tests are known, the pattern of electrophysiological changes can provide information about the VF of a child unable to perform accurate perimetry. This review summarises previously published electrophysiological findings in several common types of VF defects that can be found in paediatric patients (generalised VF defect, peripheral VF loss, central scotoma, bi-temporal hemianopia, altitudinal VF defect, quadrantanopia and homonymous hemianopia). It also shares experience on using electrophysiological testing as additional functional evidence to other tests in the clinical challenge of diagnosing or excluding VF defects in complex paediatric patients. Each type of VF defect is illustrated with one or two clinical cases.

Clinical usefulness of transient visual evoked potentials (TVEPs) and steady-state visual evoked potentials (SSVEPs) results in blind dogs

“…The retina of the right eye could not be identi ed accurately due to the presence of cataracts. In human studies, patients with retinal disease and undetectable ERG but detectable ash VEPs only perceived light or hands moving in front of their eyes [15]. The results of our study are in agreement with those of previous studies.…”

“…Depending on the location and cause of the lesion, blindness can be classi ed into three categories [15]: pre-retinal diseases, such as cataracts; retinal diseases, such as progressive retinal atrophy (PRA) or retinal detachment; and post-retinal diseases, which affect the region extending from the optic nerve to the visual cortex [15]. VEPs are objective tests that can be used to evaluate post-retinal dysfunction [1].…”

Visual electrophysiology and “the potential of the potentials”

“…There are numerous recent and anticipated developments in the field of visual electrophysiology. In 2021, a special section in this journal featured several relevant articles, each focusing on a particular aspect, summarising current knowledge, providing new insights and future directions [3,[17][18][19][20][21][22][23][24]. For the remainder of the current article, some advances, particularly relating to human ERGs, will be highlighted, categorised broadly into new devices, new stimulus protocols, and novel analyses.…”

X-Linked Retinitis Pigmentosa Gene Therapy: Preclinical Aspects

“…Patients with RP have a significant increase in the PR (pattern-reversal)-VEP latency and a decrease in amplitudes [97]. While measurement of VEP was not used widely in preclinical studies of RP, combination recording of ERG and VEP could help localize the affected visual part [98].…”