Maturation of the electroretinogram in children: stability of the amplitude ratio a/b.

We report the method and results of mesopic electroretinogram (ERG) recording by corneal electrode in 75 children aged from 0 to 15 years. This method gives an overall evaluation of the electrical activity of the retina in a rapid and acceptable manner, in the awake state and without sedation. The a- and b-waves were present at birth. The amplitude of these waves increased considerably throughout the period studied. The decrease in latencies was statistically significant only for the b-wave between birth and 6 months. The presence of oscillatory potentials increased with age. The amplitude ratio a/b remained constant at about 0.25 in all age groups. This a/b ratio thus constitutes, under the recording conditions described, a criterion of normality that is independent of age.