Background/aim: To compare the ability of confocal scanning laser tomography (CSLT), scanning laser polarimetry (SLP) and optical coherence tomography (OCT) in recognising localised retinal nerve fibre layer (RNFL) defects.
Methods: 51 eyes from 43 patients with glaucoma were identified by two observers as having RNFL defects visible on optic disc photographs. 51 eyes of 32 normal subjects were used as controls. Three masked observers evaluated CSLT, SLP and OCT images to determine subjectively the presence of localised RNFL defects.
Results: Interobserver agreement was highest with OCT, followed by SLP and CSLT (mean kappa: 0.83, 0.69 and 0.64, respectively). RNFL defects were identified in 58.8% of CSLT, 66.7% of SLP and 54.9% of OCT (p = 0.02 between SLP and OCT) by at least two observers. In the controls, 94.1% of CSLT, 84.3% of SLP and 94.1% of OCT scans, respectively, were rated as normal (p = 0.02 between CSLT and SLP, and SLP and OCT).
Conclusion: Approximately 20–40% of localised RNFL defects identified by colour optic disc photographs are not detected by CSLT, SPL or OCT. SLP showed a higher number of false-positive results than the other techniques, but also had a higher proportion of correctly identified RNFL defects in the glaucoma population.
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Funding: This study was supported by a research grant from the CIHR-MOP 62783 and 200309 and from the Canadian Glaucoma Clinical Research Council (CGCRC). BKW was supported by the Swiss National Science Foundation (SNSF) and Bangerter-Rhyner-Stiftung.
Competing interests: BKW: none; PJH: Heidelberg Engineering: S; JLS: none; BCC: Carl Zeiss Meditec: S; Heidelberg Engineering: C, S, ACB: none; DMH: none; MTN: Carl Zeiss Meditec: S, Heidelberg Engineering: S. (C, worked as a consultant for the company; S, received grants from the company.)
Ethics approval: Ethics approval was provided by the Capital District and Health Authority Research Ethics Committee.
Patient consent: Obtained.
Presented in part at the Canadian Ophthalmological Society Meeting 2007, Montreal, Canada, June 2007. The presentation was awarded with the Stephan Drance Award from the Canadian Glaucoma Society 2007.