Abstract
Purpose: :
A prominent optic nerve head (ONH) due to papilledema is a main feature in idiopathic intracranial hypertension (IIH). Early or mild elevation of the ONH may, however, not easily be distinguished from other pathologies including buried ONH drusen. Recent studies using optical coherence tomography (OCT) have shown increased retinal nerve fiber layer thickness in patients with IIH but also frequently in drusenpapillae. There is also evidence indicating disturbed cerebral venous outflow in IIH. Hence this study was performed to evaluate differences of choroidal thickness in patients with IIH compared to patients with buried ONH drusen.
Methods: :
10 patients with elevated optic disc due to IIH and 5 patients with buried ONH drusen but no other ocular pathology were examined using spectral domain OCT with enhanced depth imaging. Peripapilllary scans were used to measure average choroidal thickness and retinal nerve fiber layer thickness around the optic nerve. Transfoveal line scans were performed to assess subfoveal choroidal thickness and radial scans of the optic disc were used to measure ONH elevation.
Results: :
Optic disc elevation was comparable between the two groups (p = 0.62). Average peripapillary and subfoveal choroidal thickness were significantly increased in patients with IIH compared to patients with buried drusen (231 ± 67 µm vs. 180 ± 39 µm, p = 0.04; 381 ± 78 µm vs. 300 ± 63 µm, p = 0.01). Choroidal thickness was not associated with retinal nerve fiber layer thickness in either of the groups.
Conclusions: :
Our results indicate increased peripapilary and subfoveal choroidal thickness in patients with IIH. Together with other morphological criteria, evaluation of choroidal thickness with OCT may facilitate differential diagnosis of suspiciously elevated optic disc.
Keywords: imaging/image analysis: clinical • neuro-ophthalmology: diagnosis • optic nerve