Purpose To compare the optic disc topography measurements between the confocal scanning laser ophthalmoscopy (HRTII) and spectral-domain optical coherence tomography (Cirrus HD OCT) in normal subjects.
Methods A total of 105 eyes from 105 healthy subjects were included. The optic disc in each eye was imaged sequentially with HRT II (Heidelberg Engineering, GmbH, Dossenheim, Germany) and Cirrus HD OCT (Carl Zeiss Meditec, Dublin, CA). Paired t test was used to compare each topographic parameter between HRT2 and Cirrus HD OCT. The relationship between optic disc measurements of the 2 instruments was evaluated using a Pearson correlation analysis.
Results The mean age was 23±3.5 years. Optic disc topography measurements as determined by the 2 machines were significantly correlated (e.g disc area: r =0.78, p<0.001; rim area: r =0.45, p=0.011). HRT II measured significantly larger disc area and rim area than Cirrus HD OCT (disc area: 1.86±0.45 mm2 vs1.78±0.39 mm2, p=0.015; rim area: 1.50±0.29 mm2 vs1.34±0.27 mm2, p<0.01)
Conclusions There were significant differences in optic disc measurements as determined by HRT II and Cirrus HD OCT despite a significant correlation. Therefore, the two instruments should not be used interchangeably to obtain measurements of the optic disc for glaucoma diagnosis.