Asymmetrical Intraocular Pressures and Asymmetrical Papilloedema in Pseudotumor Cerebri Syndrome

Abstract

This report is of two cases of asymmetrical papilloedema in patients with asymmetrical intraocular pressures (IOPs). The first patient presented with headaches, transient visual obscurations (TVOs), and elevated IOPs, and was found to have increased intracranial pressure caused by a torcula meningioma. He developed papilloedema after his IOPs were pharmacologically lowered; the papilloedema resolved after the IOP became elevated again after stopping his glaucoma drops, and then again returned as the IOP reduced when the drops were restarted. The second patient with a history of Sturge-Weber syndrome requiring previous left trabeculectomy, presented with left-sided TVOs, photopsia, and pulsatile tinnitus caused by idiopathic intracranial hypertension. Asymmetrical papilloedema was observed, worse in the eye with the lower IOP following trabeculectomy. These cases suggest that asymmetric IOP may be one factor that can influence the development of asymmetric papilloedema. Ophthalmologists finding disc swelling at low normal pressures should ask about symptoms of raised ICP, and neuro-ophthalmologists confronted with asymmetrical disc swelling should routinely measure IOP. ARTICLE HISTORY

Unilateral high myopia leading to asymmetric disc edema in idiopathic intracranial hypertension

“…[ 8 ] It is believed that the translaminar pressure gradient is modulated by the intraocular pressure anteriorly and the CSF-optic nerve subarachnoid pressure posteriorly. [ 9 ] However, as in our case, the asymmetric papilledema was not associated with differential intraocular pressure between the two eyes. Another hypothesis is a possible constriction of the bony optic canal on the side with less severe disc edema, but this could not be replicated by others.…”

How to use…the direct ophthalmoscope

“…Unilateral papilloedema can occur in raised ICP 12. The prevalence of this finding is unknown but likely to be low.…”

“…The prevalence of this finding is unknown but likely to be low. This can occur because of asymmetrical intraocular pressures12 or because of asymmetrical unilateral optic atrophy, for example in Foster-Kennedy syndrome preventing one nerve from swelling due to a tumour in the anterior cranial fossa, classically in the olfactory groove 13…”

Atypical presentations of idiopathic intracranial hypertension

“…[ 29 ] Several cases of unilateral papilledema from IIH following surgical reduction of IOP for glaucoma have been described. [ 30 31 32 33 ] An experimental model in primates induced optic disc edema by lowering IOP, which resolved when IOP returned to normal. [ 34 ] Disc edema due to ocular hypotony in the primate model was histologically indistinguishable from disc edema due to raised ICP.…”