Are visually evoked potentials (VEP) useful for determination of visual acuity?: A clinical trial

Abstract

During the last decade several authors tried to measure visual acuity with visually evoked potentials (VEP). They had to restrict the applicability either to a limited vision range, with lower limit 5/10^1,2 or between 2/10 and 8/10³, or to a selected patient population, eliminating macular disease, branch vein occlusion, constricted visual field and central hemorrhagic chorioretinitis. The reason was that they had an over- or underestimation of the visual acuity due to stimulation of the complete retina, which sometimes masked true insight into the problem.

Using checkerboard patterns with high contrast level (84%, 80%, 60%) and a limited number of spatial frequencies (4, 5 or 6 different stimulus sizes), their methodology did not offer adequate and reliable clinical application^1,4.

This paper suggests the use of a more precise stimulus by decreasing the contrast level to 14% and offering a large checkerboard variety (12 sizes), enabling measurement of visual acuity with an accuracy of 1/10 (ten normal subjects); a number of patients (n=42) with ophthalmological and neuro-ophthalmological diseases were successfully investigated.

VEP thus obtained appear to be a reliable tool for the objective assessment of clinical visual acuity.

Key Words:

• visual evoked potentials
• visual acuity
• electrophysiology
• children