Abstract
Purpose:
Papilledema induced by increased intracranial pressure can result in considerable axonal damage and permanent loss of optic nerve fibers. It is, however, difficult to determine the degree of atrophic changes in swollen optic discs. Hence this study was performed to test whether individual features of optic disc morphology and peripapillary retinal nerve fiber layer (RNFL) thickness distribution in optical coherence tomography (OCT) of active papilledema are associated with nerve fiber atrophy after resolution of the swelling.
Methods:
40 patients with papilledema due to primary pseudotumor cerebri were included in this study. Measurements of peripapillary RNFL thickness using spectral domain OCT at the time of presentation and after resolution of papilledema were analyzed. Radial cross sections were used to measure intrabulbar elevation of the optic nerve head above Bruch's membrane. Patients with sectoral atrophy of the RNFL after complete resolution of papilledema were compared to patients without atrophy using unpaired t-tests. In addition, Pearson product-moment correlation coefficients were calculated to assess correlations between measured parameters.
Results:
23% of the analyzed eyes showed marked sectoral atrophy of the RNFL after complete resolution of papilledema. The initial maximum elevation of the swollen optic nerve head was found significantly higher in patients with subsequent sectoral atrophy (1155 ± 235 µm vs. 1023 ± 156 µm, p = 0.036). In addition, peripapillary RNFL thickness after resolution of papilledema correlated negatively with initial optic nerve head elevation (r = -0.51, p < 0.001) but not with initial RNFL thickness (r = -0.11, p = 0.334). Sectoral comparison of initial maximum and minimum RNFL thickness showed a significantly higher difference in eyes with subsequent sectoral atrophy (200 ± 61 µm vs. 166 ± 54 µm, p = 0.036).
Conclusions:
Our results indicate that the extent of optic nerve head elevation in papilledema caused by increased intracranial pressure is associated with sectoral atrophy of retinal nerve fibers after resolution of the swelling. In addition, sectoral comparison of peripapillary RNFL thickness in present disease seems to indicate already damaged portions of the swollen nerve fiber layer.
Keywords: 613 neuro-ophthalmology: optic nerve •
550 imaging/image analysis: clinical •
627 optic disc