Does pseudotumor cerebri cause double vision out of one eye, or out of both eyes?

Affects both eyes: Biggest issue here is increased pressure causing loss of vision if not controlled adequately. The double vision is not so rare, and involves usually, dysconjugate eye movements due to cranial nerve malfunction secondary to pressure. Maybe only one side is involved, but will affect both sides. You could patch one eye to help. But contact your neurologist, as this needs to be addressed now.

Pseudotumor: Affects both eyes, causes blured vision and at times binocular diploplia.

Monocular diplopia: can occur with pseudotumor. It is rare. Transmission of raised intracranial pressure forward through the CSF space surrounding the optic nerve can cause papilledema and this can sometimes cause a distortion in the shape of the retina that produces two images in part of the visual field from one eye. I saw my first case of this in 1989 as a neurology resident rotating through neuro-ophthalmology.

Pseudotumor cerebri: The usual cause for double vision in patients with Pseudotumor cerebri is from a sixth nerve palsy (inability to move one eye outward fully) which can be unilateral or bilateral.