Rating papilloedema: an evaluation of the Frisén classification in idiopathic intracranial hypertension

Abstract

The appearance of the optic disc is a key measure of disease status in idiopathic intracranial hypertension (IIH). The Frisén classification describes stages of optic disc swelling (grades 0-5). It is the only classification of papilloedema, and is used internationally in clinical and research practice. Despite this, there has been very limited evaluation of the scale. We assessed the inter-rater reproducibility and ability to discriminate optic disc changes over time using the Frisén classification compared with a system of ranking papilloedema severity in patients with IIH. Paired disc photographs (before and after treatment) were obtained from 47 patients with IIH (25 acute and 22 chronic). Six neuro-ophthalmologists blinded to patient identity, clinical information and chronology of the photographs reviewed the discs and allocated a Frisén grade and ranked the paired discs in order of papilloedema severity (disc ranking). A total of 188 optic disc photographs were reviewed. All six reviewers agreed in only three comparisons (1.6%) when using the Frisén classification, compared with 42 comparisons (45.2%) when using disc ranking. The probability of agreement between any two reviewers was 36.1% for Frisén grade and 70.0% for disc ranking. Disc ranking had significantly greater sensitivity for finding differences in degree of disc oedema, identifying a difference in 75.3% of paired photographs compared to 53.2% detected using the Frisén classification (p < 0.001). This study demonstrated the limited reproducibility and discriminative ability of the Frisén classification in identifying changes in serial optic disc photographs in IIH. Simple optic disc ranking appears to be a more sensitive and reliable tool to monitor changes in optic disc appearance. The use of disc ranking in clinical practice and research studies is recommended to monitor alterations in optic disc appearance until alternative schemes, specific to IIH, have been developed.

Papilledema Outcomes from the Optical Coherence Tomography Substudy of the Idiopathic Intracranial Hypertension Treatment Trial

“…In contrast, the OCT evaluated with 3-D segmentation provides continuous reliable measures that appear to reflect the effects of intra- and extra-cellular edema and axonal loss and thinning across all degrees of swelling. Frisén grade changes over time or in response to therapy can show large changes, 12 but judging grade changes when modest amounts of swelling are present is difficult.…”

OCT measurements of optic nerve head changes in idiopathic intracranial hypertension

“…Long-term papilledema results in optic nerve atrophy which may cause permanent vision loss [1]. Though often not objective or sensitive enough, severity of papilledema and vision loss constitute a basis for therapeutic intervention, but a sensitive and reliable method to monitor development of papilledema is lacking [2][3][4]. The need for more sensitive methods to register response to treatment and long-term visual outcome in patients with IIH has been emphasized [5,6].…”

Pseudotumor cerebri syndrome in childhood: incidence, clinical profile and risk factors in a national prospective population-based cohort study

“…Although CVST excludes the diagnosis of PTCS, the presence of risk factors does not and it is therefore not ‘idiopathic’. The fidelity of the clinical diagnosis of PTCS may be reduced first by misdiagnosis of papilloedema when evaluated by clinicians lacking access to specialist ophthalmological assessment12 and second by the estimation of CSF pressure based on brief recording of lumbar CSF opening pressure. This varies with posture, movement, emotion, anaesthetics and hypercapnia, and may not accurately reflect mean CSF pressure 13…”