Objective: Severity of papilledema and vision loss constitute a basis for therapeutic intervention in idiopathic intracranial hypertension (IIH), but both are often subjective and insensitive in guiding clinical management. The aim of this study was to identify reliable and sensitive measurements of optic nerve head (ONH) and macula, to provide objective guidance for prognostic evaluation and treatment in IIH. We analyzed potential of spectral domain optical coherence tomography (SD-OCT), to measure neuro-retinal rim thickness and area, optic cup-to-disc ratio (C/D) and cup volume of ONH which have not previously been reported in IIH. In parallel, thickness of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell layer (GCL) together with inner plexiform layer (IPL) (GCL-IPL) were examined.
Results: All 7 enrolled IIH patients had increased neuro-retinal rim thickness (p<0.01 for both eyes) and rim area (p<0.05), decreased C/D (p<0.01) and optic cup volume (p<0.01) when compared to findings in 18 sex- and age-matched healthy controls (HC). In a longitudinal study, two IIH patients were followed repetitively by SD-OCT before and after measurement of intracranial pressure (ICP) and removal of cerebrospinal fluid (CSF) by lumbar puncture. Rim thickness and area, C/D and optic cup volume remained altered. RNFL thickness may change with very high ICP, but not immediately after CSF removal. GCL-IPL thickness was unchanged irrespective of ICP change or CSF removal.
Conclusion: SD-OCT allows detection of ONH changes even in subtle IIH without papilledema and has potential for routine use in IIH.
Keywords: Cerebrospinal fluid; Idiopathic intracranial hypertension; Optic nerve head; Optical coherence tomography; Papilledema.
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