The paper presents the use of visual evoked potentials VEP to the objective assessment of visual acuity. Methods of using visual evoked potentials (VEP) rely on the assessment of changes of the electrical action potentials generated within the cortex. To diagnose the degree of weakening eyesight a series of studies on healthy people and visually impaired ones were made. Electrophysiological studies of the eye, using noninvasive VEP examination allow a noninvasive and objective assessment of visual acuity. The use of visual evoked potentials gives the objectivity in assessment of visual acuity what may be very important in ophthalmology. This particularly may concern children examination, people with mental retardation and suspected of simulation.