Purpose: Our aim was to apply multiple discrete wavelet transformation (DWT) types
to healthy light-adapted (cone) electroretinogram (ERG) signals in order to optimize
DWT analysy in ERG. Oscillatory potentials (OP) were individually extracted from the
signals and used to calculate an indicator for ERG analysis. Methods: Light-adapted
(LA) 3.0 cd.s/m(2) ISCEV standard ERGs were recorded from both eyes of 15 healthy
volunteers (mean age: 36.9 +/- 13.0 years old; 13 females). LA ERG signal components,
such as b-wave and OPs, were analyzed using the discrete wavelet transformation (DWT).
An index (%OPi) was proposed to estimate the individual oscillatory potentials (OP1-OP5)
by calculating the coefficient ratio of the OP to b-wave. Multiple mother wavelet
functions (i.e., Daubechies, Symlet, and Coiflet) with five orders were applied and
compared statistically using Wilcoxon tests and paired t-test comparisons with Bonferroni
posthoc analyses (p < 0.005). Results: OP4 shows the most energy at both low and high-frequency
bands (80Hz and 160Hz), while OP2 has lower energy at the lowfrequency band (80Hz)
and higher energy at the high-frequency band (160Hz). The %OP2 is the largest among
the five individual OPs. %OPs obtained with different wavelet functions differ from
each other. Db2 and sym2 seem to be the optimal wavelets for analyzing light-adapted
ERG components. Conclusion: Individual OPs of the light-adapted ERG obtained with
the DWT analysis may characterize different levels of retinal dysfunction. The %OPi
may serve as an indicator in ERG analysis.
