We performed an in-depth study of the neuro-ophthalmologic signs and symptoms of a rare but fatal disease known as primary diffuse leptomeningeal gliomatosis (PDLG). Two new cases of PDLG are described, and 22 published cases reviewed. Papilledema and sixth nerve palsy are the most common neuro-ophthalmic findings. Other abnormalities include third and fourth nerve palsies, nystagmus, and vision loss. Involvement of the visual system may be part of the initial presentation of PDLG.