Bilateral Syphilitic Optic Neuropathy with Secondary Autoimmune Optic Neuropathy and Poor Visual Outcome.

We describe the case of a 65-year-old man who suffered progressive visual loss despite appropriate treatment of ocular syphilis. Our patient initially presented with a unilateral 6th nerve palsy and associated double vision, which self-resolved over 6 months. His ophthalmic examination was otherwise normal. 12 months after the initial complaint, he represented with dyschromatopsia, reduced visual acuity, tonic pupils, and optic nerve atrophy. He tested positive for syphilis and was admitted for treatment of neurosyphilis with high-dose benzylpenicillin. Despite treatment, at a 4-month review his visual acuity remained poor and progression of optic nerve atrophy was noted alongside the development of bilateral central scotomas. Further testing was congruent with a diagnosis of autoimmune optic retinopathy. We propose this to be secondary to his syphilitic infection. Syphilis is known as the "great mimicker," and despite being quite treatable, this case highlights ongoing complexity in the diagnosis and management of syphilis, unfortunately with a poor visual outcome.

Divided visual attention: A comparison of patients with multiple sclerosis and controls, assessed with an optokinetic nystagmus suppression task.

Multiple sclerosis (MS) frequently causes impairment of cognitive function. We compared patients with MS with controls on divided visual attention tasks. The MS patients' and controls' stare optokinetic nystagmus (OKN) was recorded in response to a 24°/s full field stimulus. Suppression of the OKN response, judged by the gain, was measured during tasks dividing visual attention between the fixation target and a second stimulus, central or peripheral, static or dynamic. All participants completed the Audio Recorded Cognitive Screen. MS patients had lower gain on the baseline stare OKN. OKN suppression in divided attention tasks was the same in MS patients as in controls but in both groups was better maintained in static than in dynamic tasks. In only dynamic tasks, older age was associated with less effective OKN suppression. MS patients had lower scores on a timed attention task and on memory. There was no significant correlation between attention or memory and eye movement parameters. Attention, a complex multifaceted construct, has different neural combinations for each task. Despite impairments on some measures of attention, MS patients completed the divided visual attention tasks normally.

Optokinetic nystagmus as an assessment of visual attention to divided stimuli.

Attentional resources are finite and decline with age. We measured subjects' abilities to generate optokinetic nystagmus (OKN), to suppress it with fixation and to continue to suppress it when fixating while simultaneously paying covert attention to a feature of the optokinetic (OK) stimulus. During fixation with a red laser spot, OKN was almost fully suppressed. When subjects suppressed the OKN while simultaneously paying covert attention to a feature of the OK stimulus, suppression of the OKN was less well suppressed. The active OKN was vigorous. Age affected only the divided attention task, perhaps reflecting a diminution in resources of attention with age. The neural pathways serving attention and those serving eye movements appear to be closely related. We suggest the test presented here represents an objective measurement of the ability to divide attention, and that it has the potential to be developed for much more widespread, possibly clinical, use.

Lightning strikes twice: Leber hereditary optic neuropathy families with two pathogenic mtDNA mutations.

OBJECTIVE: To report the clinical and mitochondrial genetic analyses of two families, each of which carries both the 11778 and 14484 Leber hereditary optic neuropathy (LHON) mutations in mitochondrial DNA. METHODS: In addition to detailed clinical histories, the complete sequence of the mitochondrial DNA (mtDNA) from each family was determined. RESULTS: A small Australian LHON family (Vic20) and a family from the United States carry the 11778 and 14484 LHON mutations. In addition to the optic neuropathy, one branch of the Baltimore LHON pedigree had a high incidence of a fatal infantile encephalopathy. In both families, the 14484 LHON mutation was homoplasmic, whereas the 11778 LHON mutation was heteroplasmic. CONCLUSIONS: There are no additional mtDNA sequence changes that explain the encephalopathy in the Baltimore LHON family, and a nuclear gene involvement is an alternative explanation that is supported by the available data. The ophthalmological characteristics and penetrance in the 11778 and 14484 "two-mutation" LHON families are not markedly more severe than those of classic LHON families who carry a single mtDNA mutation.