Short Communication Received: April 20, 2016 Accepted: May 7, 2016 Published online: August 4, 2016
Ophthalmic Res DOI: 10.1159/000446659
Funduscopic versus HRT III Confocal Scanner Vertical Cup-Disc Ratio Assessment in Normal Tension and Primary Open Angle Glaucoma (The Leuven Eye Study) Koen Willekens a Sophie Bataillie a Inge Sarens a Sofie Odent a Luìs Abegão Pinto b Evelien Vandewalle a Karel Van Keer a Ingeborg Stalmans a a
Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium; b Department of Ophthalmology, Centro Hospitalar Lisboa Norte, Lisbon, Portugal
Abstract Purpose: To compare funduscopic and confocal scanning vertical cup-disc ratio (VCDR) assessments and their respective predictive value for estimating functional glaucomatous damage. Methods: Data from a single eye of open angle glaucoma patients from the Leuven Eye Study were included: age, gender, intra-ocular pressure, visual acuity, refractive error, visual field mean deviation and pattern standard deviation, funduscopic and HRT III VCDRs as well as mean retinal nerve fibre layer thickness. Non-parametric tests to compare differences within and between diagnostic groups were used, and receiver-operating characteristic curves as well as Bland-Altman plots constructed. Results: Three hundred and one eyes of 301 subjects with primary open angle glaucoma (POAG) and normal tension glaucoma (NTG) were included. The average VCDR assessed with HRT III was significantly smaller than the funduscopic measurement (0.69 ± 0.16 vs. 0.81 ± 0.14, respectively; p < 0.001). The predictive value of both measurement techniques did not differ in NTG patients, but the funduscopic estimate yielded a significantly larger predictive power in patients with severe POAG.
© 2016 S. Karger AG, Basel 0030–3747/16/0000–0000$39.50/0 E-Mail karger@karger.com www.karger.com/ore
Conclusion: Funduscopic and confocal scanner estimates of VCDR differ significantly and should not be used interchangeably. In POAG patients with severe glaucoma, a subjective VCDR predicts functional glaucomatous damage significantly better. © 2016 S. Karger AG, Basel
Introduction
Glaucoma is a neurodegenerative disorder characterized by irreversible progressive loss of retinal ganglion cells and one of the leading causes of blindness in developed countries [1, 2]. It is defined as having characteristic glaucomatous visual field and optic disc changes, i.e. thinning of the inferior and/or superior rim, vertical cup-disc ratio (VCDR) asymmetry of >0.2, not due to optic disc size asymmetry, together with matching visual field defects [3]. VCDR can be assessed rapidly by direct or indirect funduscopy and is reliably estimated with a good agreement between clinicians [4, 5]. Researchers have shown that structural damage might precede functional damage and VCDR might be altered in preperimetric glaucoma [6–8]. Therefore it is of paramount importance to investigate and measure changes in the optic disc and Ingeborg Stalmans, MD, PhD Department of Ophthalmology, University Hospitals Leuven, Campus St-Raphaël Kapucijnenvoer 33 BE–3000 Leuven (Belgium) E-Mail ingeborg.stalmans @ uzleuven.be
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Key Words Vertical cup-disc ratio · Glaucoma · Visual field