Comparison of optic disc parameters using spectral domain cirrus high-definition optical coherence tomography and confocal scanning laser ophthalmoscopy in normal eyes.

PURPOSE: To compare Cirrus HD - optical coherence tomography (HD-OCT) with confocal scanning laser ophthalmoscopy (HRT 3) for analysis of optic disc parameters in healthy eyes.

METHODS: In 126 subjects, cup volume (CV), vertical cup/disc ratio (CDR), neuroretinal rim area (NRA), cup area (CA) and optic disc area (ODA) were measured with the Cirrus HD-OCT and HRT 3. These optic disc parameters were chosen for statistical analysis because they can be analysed in both OCT and HRT 3 and they are widely used parameters for glaucoma assessment.

RESULTS: Mean values and significances of paired t-tests for OCT and HRT were for CV: 0.099 ± 0.11 versus 0.082 ± 0.10 (p < 0.001), CA: 0.42 ± 0.31 versus 0.39 ± 0.31 (p < 0.001), CDR: 0.36 ± 0.17 versus 0.27 ± 0.21 (p < 0.001). NRA and ODA were not significantly different between instruments. The Pearson coefficients were 0.905 (CV), 0.824 (CA), 0.734 (CDR), 0.295 (NRA) and 0.378 (ODA).

CONCLUSION: To our interpretation, the delineation of the optic disc border is error-prone with both instruments and all parameters directly depending on it are thus poorly correlated. However, the determination of the optic disc excavation (CV and CA) appears comparable taking into account a small systematic difference between instruments.