VEP measurement of the amplitude of accommodation.

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.