Eye movement dysfunction has been found in large numbers of schizophrenia patients and their first-degree relatives and can be studied without the interference of deficits in attention, motivation, clinical status and medication effects with relatively easy method. Eye movement dysfunction has been proposed as a useful way of expanding the schizophrenia phenotype in genetic studies. I review the literature on eye movement dysfunction with respect to syndrome and familial specificity and the quantitative assessment of eye tracking. I hope that the etiology and the pathophysiology of schizophrenia can be clarified through this eye movement study.