Peripapillary retinal nerve fiber layer thickness measurement with 3 Spectral Domain OCT devices

Abstract

AbstractPurpose To compare peripapillary retinal nerve fiber layer (pRNFL) thickness measurement using 3 Spectral Domain OCTs (SD‐OCT) in normal and glaucomatous patientsMethods Observational case series. 145 eyes of 78 patients underwent a complete examination and a standard automated perimetry followed by pRNFL OCT evaluation with the RTVue OCT (Optovue), the 3D‐OCT 2000 (Topcon) and the Spectralis (Heidelberg). Each patient was scanned by the same well‐trained examiner. pRNFL measurements were comparated across the 3 devices using repeated measures analysis of variance (ANOVA) and multiple comparaison t‐tests with Bonferroni adjustements. Bland‐Altman plots were constructed to assess the level of agreement between each pair of OCTs.Results The study included 66 normal eyes, 24 ocular hypertension, 10 preperimetric, 23 mild, 14 moderate and 8 severe glaucomas. Overall pRNFL thickness mean was greatest on the Topcon (96,2±14,9), intermediate on the RTVue (93,8±16,5) and lowest on the Spectralis (84,5±18,5). The ANOVA test demonstrated a mean thickness difference (overall, superior, inferior, nasal and temporal) between the 3 OCTs (p<0,05). On the multiple comparaisons t‐test, the Topcon and RTvue were not significantly differents. The bland Altman plots show a moderate agreement but a good correlation between the 3 OCTs. The thinner were the RNFL thickness, the greater were the differences between the devices.Conclusion This study proved that there were differences in the thickness measurements and a moderate agreement between the 3 devices. SD‐OCT are not interchangeable and the patient's follow up should be done on the same device.