The amplitude of accommodation was measured in 44 subjects by visually evoked potentials (VEP) in response to negative lenses. It was found that about two-thirds of the subjects responded to the lenses by increasing their accommodation in order to minimise blur, while the other one-third accepted the blur and accommodated very little. The amplitude was also determined subjectively (push-up method) and it correlated very well with the VEP measurement (r = 0.91). It is therefore suggested that VEP constitutes a feasible method of assessing objectively the amplitude of accommodation.