The object of this study is to investigate the changes of the pattern reversal VEP in the malingering optical function according to the check-size and contrast of pattern reversal checkboard. The four different methods of malingering were de-focusing, eye-moving, out-gazing, non-concentrating. The results were follows:

1) The N1, P1 latency of normal eyes were significantly delayed in the small check-size compared with the middle and large check-sizes. And the N1-P1 amplitude was not changed according to the check-size differences.

2) The N1-P1 amplitude of normal eyes were not significantly changed according to the check-size and contrast differences.

3) In the malingering, the de-focusing method showed the significant delay of N1, P1 latency and the reduction of amplitude compared with the normal eyes.

4) The eye-moving method of malingering showed only the reduction of amplitude and no change of the latency.

5) The out-gazing malingering showed no VEP potentials in all the subjects, and non-concentrating method showed no change of the latency and amplitude compared with the normal eyes.

This results suggest that malingering methods of de-focusing, eye-moving and out-gazing can change the results of pattern reversal VEP latency and amplitude significantly and this changes must be considered in the clinical examination for the objective and precise assessment of optical function.