Article Text
Abstract
Background Assessment of spectral-domain optical coherence tomography (SD-OCT) compared with visual fields, to detect progression across the glaucoma spectrum.
Methods In this study, adult glaucoma suspects and patients, with baseline retinal nerve fibre layer (RNFL) thickness on SD-OCT and reliable visual field (VF) tests on Humphrey Field Analyser (HFA) prior to March 2010, were recruited. Functional and structural progression over at least 5 years was compared using Glaucoma Progression Analysis (GPA) and VF index (VFI) on HFA and Guided Progression Analysis (GPA-OCT) on SD-OCT, respectively. Agreement of progression detection between the two modalities was computed using κ statistics.
Results 122 subjects (63 glaucoma suspects; 59 glaucoma patients) were enrolled. Of 18 suspects who progressed to glaucoma, 13 showed progression by GPA-OCT, 4 by GPA, 7 by VFI and 2 were concordant. In the 14 glaucoma patients who progressed, GPA-OCT detected progression in 6, GPA in five and VFI in six. GPA-OCT had poor agreement with GPA in glaucoma suspects (Kappa 0.15; p=0.13) and patients (Kappa 0.10; p=0.45). VFI had better agreement with GPA-OCT in glaucoma suspects (Kappa 0.34; p=0.01) than glaucoma patients (Kappa 0.12; p=0.36). Progressors by VF in both groups had similar percentage change from baseline RNFL thickness (−9.9% vs −8.6% p=0.46), even though the absolute change was significantly greater in suspects(−8.75µ vs−6.4µ p=0.03).
Conclusion Structural change appears to be more useful to detect progression in glaucoma suspects, while functional change is a better indicator as the disease progresses. Percentage change from baseline RNFL thickness was a better measure than absolute change in RNFL.
- retinal nerve fibre layer
- glaucoma progression
- GPA
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Footnotes
Contributors All authors made substantial contributions to the conception or design of the work or the acquisition, analysis or interpretation of data for the work: NG, SK1, SK2, SR, SSP. Drafting the work or revising it critically for important intellectual content: NG, SK1, SK2. Final approval of the version to be published: SK, SSP. Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved: NG, SK1, SK2, SR, SSP. I “SK” the corresponding author of this article contained within the original manuscript which includes any diagrams and photographs and any related or stand alone film submitted (the Contribution) has the right to grant on behalf of all authors and does grant on behalf of all authors a licence to the BMJ Publishing Group Ltd (BMJ) and its licensees to permit this Contribution (if accepted) to be published in any BMJ products and to exploit all subsidiary rights, as set out in our licence set out at: http://group.bmj.com/products/journals/instructions-forauthors/wholly_owned_licence.pdf.
Disclaimer The guarantor (Sushmita Kaushik; SK1) accepts full responsibility for the work and/or the conduct of the study, had access to the data and controlled the decision to publish.
Competing interests None declared.
Patient consent Informed consent was taken form all enrolled patients
Ethics approval Institute Ethics Committee, PGIMER, Chandigarh.
Provenance and peer review Not commissioned; externally peer reviewed.
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