In this report, we provide clinical information on the diagnosis of postretinal blindness in veterinary ophthalmology. We have diagnosed three dogs with postretinal blindness (bilateral in one case and in the left eye in two cases). The electroretinogram results were normal and the optic axis was relatively clear in all cases. Our findings indicate that the reason for the blindness in these dogs was an intracranial lesion. Fundus photography did not reveal any significant changes, except in the optic disc. A normal optic disc, an optic disc that appeared to be smaller than that in the other eye, and a severely hyperemic and edematous optic disc were seen in cases 1, 2, and 3, respectively. On magnetic resonance imaging, two dogs had optic chiasm lesions (one a tumor, one inflammation) and the remaining dog had inflammation in the right optic tract and occipital lobe even though bright flash electroretinograms were normal. Magnetic resonance imaging and electroretinography can be used as diagnostic tools for detection and localization of central nervous system lesions in the visual pathways.