Faculty Bibliography

The quantitative assessment of visual function in multiple sclerosis (MS) clinical trials has been limited to Snellen visual acuity. The purpose of this study was to examine the inter-rater reliability and test characteristics of a new visual outcome measure, the Low-Contrast Sloan Letter Charts, in patients with MS and visually-asymptomatic volunteers. Contrast letter acuity scores (letter scores) were measured at each of four contrast levels (100, 5, 1.25 and 0.6%) by two independent raters. Inter-rater agreement was described with the intraclass correlation coefficient (ICC) and comparison of mean scores. Excellent inter-rater agreement (ICC=0.86 - 0.95) was demonstrated at each contrast level among MS patients (n=100) and visually-asymptomatic volunteers (n=33). Average letter scores at the lowest contrast level (0.6%) were highly variable in the MS group, even among patients with visual acuities of 20/20 or better, and among those who required no assistance for ambulation. Low-Contrast Sloan Letter Chart testing is a highly reliable method of visual assessment, and provides information on an aspect of neurologic impairment in MS which is not captured by Snellen visual acuity or ambulation status. This new method demonstrates excellent potential as a visual function outcome measure for future MS clinical trials.

Neuro-ophthalmologic disorders affecting the afferent and efferent visual systems are frequently encountered by neurosurgeons in clinical practice. This article focuses on aspects of neuroanatomy that are most important to the diagnosis of afferent and efferent visual pathway lesions. The use of optic disc and fundus appearance, visual fields, and ocular motility and pupillary findings are emphasized in the discussions of topographic diagnosis.

The relation between obesity and age in children with idiopathic intracranial hypertension (pseudotumor cerebri) has remained uncertain. The authors reviewed the records of 45 consecutive children with newly diagnosed idiopathic intracranial hypertension seen at two medical centers. Forty-three percent of patients aged 3 to 11 years were obese, whereas 81% of those in the 12- to 14-year age group and 91% of those in the 15- to 17-year age group met criteria for obesity (p = 0.01). Younger children with idiopathic intracranial hypertension are less likely to be obese than are older children or adults.

Patients with Ollier's disease (multiple skeletal enchondromas) and Maffucci's syndrome (multiple enchondromas associated with subcutaneous hemangiomas) may develop skull base chondrosarcomas or low-grade astrocytomas as a delayed consequence of these disorders. We report three patients with Ollier's disease and Maffucci's syndrome who had diplopia as the initial manifestation of intracranial tumors. Since patients with Maffucci's syndrome and Ollier's disease are at risk for the delayed development of brain and systemic neoplasms, neuroophthalmologists must be aware of the need for long-term surveillance in patients affected by these conditions.

OBJECTIVE: To report four children with visual impairment associated with mutism after posterior fossa surgery. Mutism after posterior fossa surgery is a well-described phenomena, but to our knowledge, visual impairment has not been reported in association with it. METHODS: Record review of four children (age range, 3-7 yr) who underwent posterior fossa surgery (via suboccipital craniotomies) for removal of a medulloblastoma (three patients) or ependymoma (one patient). Each presented with headache, ataxia, or nausea and vomiting, but none had preoperative visual complaints other than diplopia. Postoperatively, all patients were mute, and because of apparent visual loss, neuro-ophthalmic consultation was requested. Postoperative scans and examinations were also reviewed. RESULTS: Each child was awake but appeared withdrawn without verbal output. No child blinked to threat or fixed or followed. In each case, pupillary reactivity was normal, and funduscopic examinations revealed only papilledema. One child reached for money. Within weeks or months postoperatively, the mutism spontaneously resolved, and visual behavior in general improved, roughly in parallel. During the follow-up period, papilledema resolved and the disc color was normal in each case. Magnetic resonance images obtained postoperatively revealed nothing remarkable, except surgical defects, without lesions in the retrogeniculate pathway. CONCLUSION: Impaired visual behavior, mimicking cortical visual loss, may be associated with mutism after posterior fossa surgery in children. The prognosis for recovery is excellent and parallels the return of normal speech. The mechanism is unclear.