Pattern visual evoked potentials: their use in pediatric ophthalmology.

The purpose of this chapter has been to demonstrate that the VEP can be used as an objective measure of visual function in infants and young children. It provides the clinician with a quantifiable index of visual impairment, and indeed may be useful in predicting a reduction of subjective visual acuity before it is found on clinical examination. There is no doubt that such abnormalities as strabismus, cataracts, ptosis, and corneal opacities can be detected on clinical examination without the aid of VEPs; however, the VEP may determine, particularly in preverbal children, whether and to what extent that abnormality has caused an impairment in acuity. The assumption is made in the case of a monocular reduction in acuity that if VEP amplitudes from the two eyes are not equal, visual acuity is not equal. This is a valid assumption since there is a correlation between reduced visual acuity and VEP amplitudes in older children with amblyopia who give reliable subjective acuities. In addition to the detection and evaluation of acuity loss in infants and children, the VEP offers a way of monitoring the efficacy of occlusion therapy and CAM therapy. Also the VEP can be used to monitor the effects of corneal and lens opacities on visual development.