Repeatability of peripapillary retinal nerve fiber layer and inner retinal thickness among two spectral domain optical coherence tomography devices.

PURPOSE: To compare measurement of macular inner retina and peripapillary retinal nerve fiber layer (pRNFL) thickness using two spectral-domain optical coherence tomography (SD-OCT) devices in glaucoma patients, patients with ocular hypertension, idiopathic and atypical Parkinson disease, and healthy controls. METHODS: A total of 171 eyes of 146 participants underwent successful pRNFL and macular scanning and automated measurement of ganglion cell layer+inner plexiform layer (GCL-IPL) using Cirrus HD-OCT or retinal nerve fiber layer+GCL-IPL (RNFL-GCL-IPL) using RTVue-100. Macular RNFL was added to the GCL-IPL thickness measured by Cirrus and was compared to the RNFL-GCL-IPL thickness of the RTVue in the corresponding Cirrus sectors. Intraclass correlation coefficient (ICC) was calculated to determine repeatability of three consecutive measurements; ICC and Bland-Altman analysis to assess agreement between OCTs; Pearson's correlation coefficient to assess strength of linear correlation. RESULTS: Repeatability of average macular RNFL-GCL-IPL thickness measurement was excellent with an ICC of 0.998 for Cirrus and 0.995 for RTVue. Repeatability was also good for average pRNFL thickness measurements. Both instruments demonstrated a good consistency in measurements with ICC values ranging from 0.844 to 0.862 for macular RNFL-GCL-IPL and 0.718 to 0.958 for pRNFL thickness. CONCLUSIONS: Measurement of pRNFL and macular RNFL-GCL-IPL thickness has a high degree of repeatability for both OCT devices. Despite a high correlation between measurements of the two OCT devices and fair to excellent ICC values representing a high consistency in the measurements of the two devices, RTVue measured a thicker macular RNFL-GCL-IPL and pRNFL thickness.