ABSTRACT
The physiologic effects of maturation and aging on visual electrophysiologic responses are numerous. These influences need to be considered when interpreting electrophysiologic results. Electrophysiologic recording in infants presents unique challenges, and techniques for estimating visual acuity in preverbal children are available. This chapter covers these topics as well as gender and amblyopia. The outline of the chapter is as follows:
Maturation Delayed visual maturation Electrophysiologic testing in infants Estimating visual acuity in infants Amblyopia Aging Gender
MATURATION
The visual system is not fully developed at birth. The foveal pit is incomplete, and the foveal cone photoreceptors are immature. Myelination of the optic nerve is unfinished, and synapses at the lateral geniculate nucleus and the occipital lobe are underdeveloped. Subsequent development and maturation of the visual system require physiologic maturation and environmental visual stimulation. While studies of maturation of VEP and full-field ERG responses are readily available, similar investigations of focal ERG, multifocal ERG, and pattern ERG are more limited in young patients because of difficulty in maintaining required fixation. Obtaining EOG is also difficult in young patients because of the cooperation needed to perform voluntary eye movements.
