Diagnostic accuracy of optic nerve OCT and ultrasound in a large paediatric cohort referred with suspected papilloedema and very low rates of raised ICP.

Abstract

Background/objectives: The Honey Rose trial increased referrals for suspected papilloedema. We audited such referrals from community optometrists and used long-term patient outcomes to investigate the diagnostic accuracy of OCT retinal nerve fibre layer (RNFL) thickness and B scan ultrasound optic nerve sheath diameter (ONSD) for raised intracranial pressure (rICP).

Subjects/methods: Audit of 337 children seen in a 'blurry disc' clinic. Long-term outcomes (6-42 months) were used to classify children as with or without raised ICP. Receiver operating curves investigated diagnostic accuracy of RNFL and ONSD cut-off values. Regression modelling investigated potential predictive variables for rICP.

Results: 310/337 children (92%) were discharged, 75 of whom were reviewed due to some clinical suspicion. 27/337 children (8%) were referred to other specialists, of whom 18 had rICP (16 IIH, one intra-cranial tumour, one arachnoid cyst). RNFL thickness cut-off >144 µm at 95% specificity had 83% sensitivity (95% CI 61-100%) and ONSD cut-off >4.99 mm at 90% specificity had 82% sensitivity (95% CI 50-100%) for rICP. Increased RNFL thickness, increased ONSD and presence of symptoms all contributed to prediction of rICP: acuity, age, sex and all other OCT parameters did not.

Conclusions: 95% (319/337) of children referred with suspected papilloedema did not have raised ICP. Almost three-quarters of children referred (253/337, 70%) would have been more appropriately managed in community optometry. OCT RNFL and ONSD cut-offs show promising diagnostic accuracy for rICP in this study. There is a clear need to support community optometry to resume management of most children with suspected papilloedema.