Flicker electroretinogram in newborn infants

Abstract

Purpose To develop and validate a flicker electroretinogram (ERG) protocol in term-born neonates as a potential tool for assessing preterm infants at risk of developing retinopathy of prematurity. Methods A custom flicker ERG protocol was developed for use with the hand-held RETeval® electrophysiology device. Feasibility of measuring flicker ERG through closed eyelids and without mydriasis was established in a pilot study enabling optimisation of the test protocol. Following this, healthy term-born neonates (gestational age 37–42 weeks) were recruited at the Neonatology clinic of the University Hospital Zurich. Flicker ERG recordings were performed using proprietary disposable skin electrodes during the first four days of life when the infants were sleeping. Flicker stimuli were presented at 28.3 Hz for a stimulus series at 3, 6, 12, 30, and 50 cd·s/m2, with two measurements at each stimulus level. Results were analysed offline. Flicker ERG peak times and amplitudes were derived from the averaged measurements per stimulus level for each subject. Results 28 term-born neonates were included in the analysis. All infants tolerated the testing procedure well. Flicker ERG recording was achieved in all subjects with reproducible flicker ERG waveforms for 30 and 50 cd·s/m2 stimuli. Reproducible ERGs were recorded in the majority of infants for the weaker stimuli (with detectable ERGs in 20/28, 25/28, and 27/28 at 3, 6, and 12 cd·s/m2, respectively). Flicker ERG amplitudes increased with increasing stimulus strength, with peak times concurrently decreasing slightly. Conclusion Flicker ERG recording is feasible and reliably recorded in sleeping neonates through closed eyelids using skin electrodes and without mydriasis. Flicker ERG amplitude decreases for lower luminance flicker but remains detectable for 3 cd·s/m2 flicker in the majority of healthy term-born neonates. These data provide a basis to study retinal function in premature infants using this protocol.

Flicker electroretinogram in preterm infants

“…From previous recordings in term-born infants, we knew that movements of infants during recording led to noisier and less reproducible ERG waveforms. (29) With this in mind, we tried to test the infants in optimal conditions. We recorded ERGs while infants were sleeping, after feeding when possible, and ensured that they were in a comfortable position.…”

“…At the time of testing, Myo-Trace® electrodes were the only electrodes commercially available that were physically small enough to be used in extremely preterm infants. To compare data obtained in prematurely born infants with those previously obtained in term-born babies using different electrodes (29), we carried out an electrode comparison in a new infant cohort. Our icker ERG protocol was used to test both eyes of 10 term-born infants, using Myo-Trace® electrodes in the rst eye followed by RETeval Sensorstrip® (LKC Technologies Inc.) electrodes in the fellow eye.…”

The Use of the RETeval Portable Electroretinography Device for Low-Cost Screening: A Mini-Review

“…Interestingly, ERG parameters associated with the development of mild ROP symptoms were comparable to those of healthy subjects later in life, while the two infants who progressed to severe ROP in the study exhibited reduced light-adapted b-wave sensitivity and saturated amplitudes prior to treatment 42 . More recently, a study reported measurable RETeval ERG recordings performed with the skin sensor strip electrodes and closed eyelids 43 , strengthening the value of the portable device as a gentle procedure in a more vulnerable patient population.…”

Visual electrophysiology and “the potential of the potentials”

“…Figure 2 illustrates the device and example waveforms. Many publications have emerged reporting its use in diverse conditions including diabetic retinopathy, a range of inherited retinal diseases, birdshot chorioretinopathy, glaucoma, idiopathic intracranial hypertension, and others [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47].…”

“…These are summarised in Table 3. Some have been incorporated in portable devices, with findings reported in several studies [3,31,33,35,36,39]. An ISCEV guide has been published reviewing the range of standard and extended protocols [53].…”