PurposePattern onset VEPs do not always show distinct C1–C2–C3 peaks and troughs. Our purpose was to study changes in pattern onset VEP with age to determine when the illustrated ISCEV standard onset VEP waveform can be reliably recorded.MethodsWe recorded pattern onset VEPs from an Oz electrode referred to mid-frontal electrode according to ISCEV standards by presenting checks of 60′ and 15′ side length in a 15° field. Twenty-four adults aged 20–63 years participated. Amplitudes and latencies were collated. Pattern onset adult VEP shapes were compared to the waveform published in the ISCEV VEP standard and to paediatric pattern onset VEP waveforms recorded from 16 infants aged 7 months.ResultsThe shape of the pattern onset VEP changed gradually with age. The C1–C2–C3 morphology of the ISCEV standard pattern onset VEP becomes apparent consistently after 40 years to 60′ check stimulation. As age increases a negative trough, C2 is more frequently seen; however, the broad positive peak which characterises infant onset VEPs may still be recorded at 20 years. The group median measurements of onset VEPs to 60′ were C1 7 µV@ 88 ms (range 67–110 ms), C2 9 µV@109 ms (range 89–158 ms) and C3 13 µV@121–246 ms. To smaller 15′ checks, peak latencies were earlier and C2 became more obvious. The group median measures of onset VEPs to 15′ were C1 2 µV@69 ms (55–108 ms), C2 10 µV@90 ms (77–145 ms) and C3 14 µV@122 ms (99–200 ms).ConclusionThe ISCEV standard onset VEP best describes the waveform configuration and latency of the onset VEP produced by 60′ checks in adults of more than 40 years of age. The onset VEP waveform produced by 15′ checks is distinguished by more prominent negative C2 and earlier C1 and C2 latencies.

PURPOSE. Our aim was to elaborate how on and off signals contribute to pattern ERGs and pattern visual evoked potentials (VEPs) by using pedestal patterns arising from incremental and decremental onset stimulation.METHODS. Pattern onset/offset ERGs and VEPs were produced by black and white checks of 60 0 side length and 88% spatial contrast appearing in a 168 field for 200 ms from white (110 cd/m 2 ), black (7 cd/m 2 ), and gray (48 cd/m 2 ) backgrounds and disappeared for 1000 ms. Twenty healthy subjects participated in the study (median age 19.5, range, 5-31 years), 10 of whom also underwent pattern onset/offset ERG recordings to the same stimuli (median age 25.7, range, 22-31 years). VEPs were recorded from an occipital array referred to Fz. Pattern electroretinograms (PERGs) were recorded from ''Dawson-Trick-Litzkow'' (DTL) plus corneal electrodes referred to ipsilateral outer canthi.RESULTS. There was high correlation within subjects of the VEP waveform produced by patterns arising from light increment and decrement (group mean correlation coefficient of PVEPs to check appearance from black versus white: 87%). An average of increment and decrement PERGs simulated the onset PERG from a gray background. This waveform is akin to standard International Society for Clinical Electrophysiology of Vision (ISCEV) clinical PERGs to reversing checks.CONCLUSIONS. In healthy individuals, the early components of the pattern onset/offset VEP waveforms are comparable to light increment and decrement pedestal stimulation. Pattern onset/offset ERGs to pedestal stimulation may be used to probe simultaneous recording of ERGs with VEPs in order to obtain an assessment of retinal ganglion cell and optic pathway function in patients with less stable fixation.