Objective To investigate the agreement between scanning laser ophthalmoscopy (Heidelberg retinal tomograph 3; HRT-3) and high-definition optical coherence tomography (HD–OCT) for measurements of optic nerve head (ONH) parameters.
Methods As part of a population-based cross-sectional study, 913 consecutive Chinese subjects aged 40 years and older underwent HRT-3 and HD–OCT imaging of the ONH after pupillary dilation. Limits of agreement (LOA) derived from Bland–Altman analysis were calculated for ONH measurements.
Results The mean age (±SD) of study participants was 54.2±7.2 years and 52.0% were men. The two instruments showed no difference in mean optic disc area measurements (1.98±0.37 for HD–OCT vs 1.98±0.39 mm for HRT-3, p=0.95). HD–OCT showed smaller rim area (1.29±0.24 vs 1.46±0.27 mm, p<0.001), but bigger cup-related parameters (p<0.001 for all) than HRT-3. The highest correlations between the instruments were observed for cup volume (r2=0.74, p<0.001) and disc area (r2=0.62, p<0.001). The correlations for cup-to-disc ratio (CDR), vertical CDR and rim area were lower (r2=0.59, 0.48 and 0.24, respectively, p<0.001 for all). The Bland–Altman plots demonstrated significant proportional bias for differences in all ONH parameters (p<0.01 for all), with LOA greater for disc-related parameters (0.98–1.0) than cup-related parameters (0.26–0.50).
Conclusions There are substantial disagreements between HRT-3 and HD–OCT in ONH measurements. Although optic disc area measurements were similar, HD–OCT underestimates the rim area and overestimates cup parameters compared with HRT-3.
- Anterior chamber
- clinical trial
- diagnostic tests/investigation
- intraocular pressure
- lens and zonules
- public health
- treatment surgery
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Funding This work was supported by a grant from the Biomedical Research Council, Singapore, grant number 08/1/35/19/550. TA and TYW have received grant funding from Carl Zeiss Meditec but this was not related to the subject of this study. TA has received travel support and honoraria from Carl Zeiss Meditec.
Competing interests None.
Patient consent Obtained.
Ethics approval Approval for the study was granted by the Singapore Eye Research Institute institutional review board.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement TA has the data for the study, is responsible for the data integrity and holds all additional unpublished data.