Remember the retina: retinal disorders presenting to neurologists.

General neurologists and stroke specialists are regularly referred cases of visual disturbance by general practitioners, emergency doctors and even ophthalmologists. Particularly when the referral comes from ophthalmologists, our assessment tends to focus on the optic nerve; however, retinal conditions may mimic optic neuropathy and are easily missed. Their diagnosis requires specific investigations that are rarely available in a neurology clinic. This article focuses on how a general neurologist can identify retinal problems from the clinical assessment and how to proceed with initial investigations. The following cases were all referred to a consultant neurologist (GTP) from ophthalmology services as optic neuropathies or other neurological disorders. Part A of the summary describes the presentation and findings in the neurology clinic; part B describes the subsequent specialist assessment in the neuro-ophthalmology/eye clinic.

Internuclear ophthalmoplegia.

A brainstem lesion of any type that involves the medial longitudinal fasciculus (MLF) can cause internuclear ophthalmoplegia (INO). This primarily affects conjugate horizontal gaze and classically manifests as impaired adduction ipsilateral to the lesion and abduction nystagmus contralateral to the lesion. Here, we describe the anatomy of the MLF and review the clinical features of INO. We also describe conjugate horizontal gaze palsy and some of the 'INO-plus' syndromes.

Asymmetrical Intraocular Pressures and Asymmetrical Papilloedema in Pseudotumor Cerebri Syndrome.

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.