Diagnosis of postretinal blindness caused by intracranial disease in three dogs

In this report, we provide clinical information on the diagnosis of postretinal blindness in veterinary ophthalmology. We havediagnosed three dogs with postretinal blindness (bilateral in one case and in the left eye in two cases). The electroretinogram resultswere normal and the optic axis was relatively clear in all cases. Our findings indicate that the reason for the blindness in these dogswas an intracranial lesion. Fundus photography did not reveal any significant changes, except in the optic disc. A normal optic disc, anoptic disc that appeared to be smaller than that in the other eye, and a severely hyperemic and edematous optic disc were seen in cases1, 2, and 3, respectively. On magnetic resonance imaging, two dogs had optic chiasm lesions (one a tumor, one inflammation) and theremaining 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 nervoussystem lesions in the visual pathways.

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