Electrophysiological studies showed that a patient with Aland eye disease had no misrouting of the optic pathways which is always found in all forms of albinism as a consequence of the retino-geniculate anomaly. Also the spontaneous and optokinetic nystagmus did not resemble that of the large majority of human albinos. The marked asymmetry found in this patient seems to be typical for humans with a defective development of foveal binocular vision. These findings are in agreement with clinical, nystagmographic and EM findings that Aland eye disease is distinct from the Nettleship-Falls type of X-linked ocular albinism. Furthermore, Aland eye disease is different from X-chromosomal congenital stationary night blindness with myopia by the fact that the scotopic functions are only moderately affected and there is no restriction of the peripheral photopic visual fields. In addition, there is latent nystagmus of extraocular type that appears also in female carriers. There is no ophthalmoplegia, there is a progression of the myopia and the dyschromatopsia is of secondary type.