QUANTITATIVE-EVALUATION OF PAPILLEDEMA IN PSEUDOTUMOR CEREBRI

PURPOSE. TO determine the feasibility of adapting confocal scanning la ser (CSL) tomography of the optic disc for quantitative evaluation of papilledema in pseudotumor cerebri (PTC). METHODS. Confocal scanning l aser tomography of the optic disc was performed in 11 patients with di agnosed PTC and 12 visually normal control subjects of similar age. In five patients with active papilledema, CSL tomography was performed s erially over several months. To quantify optic disc characteristics, s urface topography was measured in 0.1-mm steps along the horizontal an d vertical meridians and four oblique meridians. Best fit polynomial f unctions, describing surface topography along each meridian, were deri ved using linear regression analysis. RESULTS. Third-order polynomials provided excellent fits (significantly better than the second-order f unctions) to the surface topography for all meridians in the control s ubjects and patients with PTC. In control subjects and PTC patients an asymmetry in the slope of the optic disc contours was evident along t he horizontal but not the vertical meridian. In patients with active p apilledema a significant elevation of the center of the disc was accom panied by a change in overall surface topography. Each of the PTC pati ents followed up serially had a pronounced posterior deformation of th e disc (i.e., a reduction in papilledema) that was initially apparent in the temporal meridian and did not proceed uniformly across all meri dians. CONCLUSIONS. Confocal scanning laser tomography can quantify th e magnitude and monitor the resolution of papilledema in PTC. Studies of optic nerve head topography may provide further insight into optic nerve compliance with elevated intracranial pressure.