Background and purpose
There is a need to improve the diagnostic process of patients suspected of papilledema. In patients with known or suspected idiopathic intracranial hypertension a fundus imaging and perimetric visual field assessment system (COMPASS) performed at a headache center was validated in comparison to an assessment (Topcon plus OCTOPUS) at a neuroophthalmological clinic.

Methods
For intermethod assessment, blinded fundus images and perimetry from COMPASS versus Topcon plus OCTOPUS were assessed by a neuroophthalmologist. For interrater assessment, fundus images and perimetry obtained by the COMPASS system were assessed by an untrained medical doctor, a trained neurologist and a trained medical student and compared to the neuroophthalmologist's assessments.

Results
For the intermethod variation of the presence of papilledema on fundus images, a kappa value of 0.60, sensitivity of 87% and specificity of 73% were found. The interrater variation of the presence of papilledema on fundus images showed kappa values ranging from 0.43 to 0.74, sensitivity values ranging from 70% to 96% and specificity values ranging from 46% to 93% when comparing the assessments made by the headache center staff with neuroophthalmologist's assessments. The COMPASS showed a 59% sensitivity and moderate agreement in detecting visual field defects compared with OCTOPUS. The visual field assessment showed only slight to fair agreement from 0.19 to 0.31 between assessments made by the headache center staff and the neuroophthalmologist.

Conclusion
The COMPASS system can be used with reasonable sensitivity in the assessment of papilledema in patients suspected of idiopathic intracranial hypertension at a tertiary headache center.