The digital Cullen chart: a red colour perimetry aid for visual field examination

Abstract

Background: 30 years ago, a paper chart was developed in Edinburgh by Cullen et al. and validated as a swift, supplementary method for perimetric evaluation of visual fields. We have re-developed this concept in digital form (on smartphone screen) and assessed its sensitivity and specificity in detecting visual field loss, by comparison with formal machine-based perimetry.

Methods: Patients with sellar and parasellar tumours, being managed in a single neurosurgical centre, underwent formal visual field perimetry as part of standard care. They also underwent assessment using the smartphone-based Cullen chart. 37 eye testing episodes were assessed, incorporating pre- and post-treatment assessments for a range of potentially compressive pathologies (non-secretory and secretory pituitary adenoma, craniopharyngioma, and parasellar meningioma). The smartphone-based Cullen chart was compared with formal machine-based perimetry for concordance in detecting visual field loss.

Results: The digital Cullen chart had a sensitivity of 75% and specificity of 98% compared with machine-based perimeters. The positive predictive value was 93% and the negative predictive value was 92%.

Conclusions: For the visual field assessment of patients with sellar/parasellar tumours, this simple and swift smartphone-based chart shows good concordance with machine-based perimeters. With amendments to the user interface, there may be potential for telemetric patient-led visual field monitoring.

Keywords: Visual field; pituitary surgery; smartphone; suprasellar.