To compare circumpapillary retinal nerve fiber layer (RNFL) thicknesses as measured using five different optical coherence tomography (OCT) devices.

RNFL thickness was measured in 32 healthy eyes of 32 subjects using a Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA, USA), Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany), Topcon DRI OCT (Topcon, Tokyo, Japan), RS-3000 Advance OCT (NIDEK, Aichi, Japan), and RTVue-100 (Optovue, Fremont, CA, USA). Global and quadrant (superior, nasal, inferior, and temporal) RNFL thicknesses were compared using repeated measures analysis of variance, and the agreement among devices was determined using Bland-Altman analyses.

The global RNFL thickness was greatest when measured using the Topcon DRI OCT, with a mean value of 107.5 µm. The mean global RNFL thicknesses measured using the RTVue-100, RS-3000 Advance OCT, and Spectralis OCT were 104.9 ± 8.4, 104.4 ± 9.4, 102.5 ± 8.9 µm, respectively. The Cirrus HD-OCT presented the thinnest RNFL measurement, with a mean value of 97.7 ± 8.7 µm ( p < 0.01). A similar pattern was found for the quadrant RNFL thicknesses ( p < 0.01). Differences in the global RNFL thicknesses among the devices ranged from 0.5 to 9.9 µm. The limits of agreement of the global RNFL thicknesses evaluated by Bland-Altman analyses ranged from 6.8 to 19.6 µm.

RNFL thicknesses measured using five different OCT devices were not interchangeable and there was a wide limit of agreement. When interpreting RNFL thickness values determined by different devices, caution is advised.