Asymmetric papilledema in idiopathic intracranial hypertension: prospective interocular comparison of sensory visual function.

Abstract

PURPOSE: Visual loss is the main morbidity of idiopathic intracranial hypertension (IIH). The relationship between papilledema grade and visual loss is unclear. The goal of this study was to determine whether there is a relationship between papilledema grade and visual loss. METHODS: Fundus photographs of 478 patients with IIH were reviewed, and their degree of papilledema was graded using Frisén's scheme. We identified 46 patients (10%) with IIH and highly asymmetric papilledema, as defined by an interocular difference of two or more grades. Nine of these patients with active asymmetry agreed to return for a series of visual tests. They underwent three visual field tests-Humphrey visual field analyzer 24-2, motion perimetry, and ring perimetry. The perimetry outcome measures were mean deviation, foveal threshold, and means for eccentric zones (3 degrees, 9 degrees, 15 degrees, and 21 degrees). The patients participated also in visual acuity, Farnsworth-Munsell 100-hue, Pelli-Robson contrast sensitivity, and foveal flicker fusion testing. Their relative afferent pupillary defect was graded using neutral density filters. RESULTS: The intereye comparisons showed vision to be worse in the eye with the high-grade papilledema for all outcome measures. The magnitude of the loss with the perimetry tests increased with eccentricity. The measures of central visual function, although in the normal range, were relatively depressed in the eye with high-grade papilledema. CONCLUSIONS: Visual loss in patients with asymmetric papilledema caused by IIH was most pronounced in the eye with the higher grade of papilledema. Foveal visual functions, although they remained in the normal range, were also decreased in patients with high-grade papilledema. In patients with high-grade papilledema, visual loss appeared to affect the entire visual field, and the peripheral field showed the most deficit. Our findings showed that high-grade papilledema was associated with visual dysfunction in patients with IIH.