Abstract
Previous studies of repeatability and reproducibility have found the StratusOCT to be a reliable measure of simple retinal thicknesses(1–5). New measures of retinal structure based on the longitudinal reflectivity profile (LRP) may provide additional information about retinal structure. The measures include total retinal thickness (TRT), inner retinal thickness (IRT), inner segment and outer nuclear layer thickness (IS+ONLT), outer segment and retinal pigment epithelial thickness (OS+RPET), retinal nerve fibre layer relative reflectivity (RNFLR) and inner segment/outer segment relative reflectivity (IS/R).
Intrasession repeatability and intersession reproducibility were examined in 64 and 29 normal subjects respectively using a custom scan protocol. Scans were taken along the horizontal and vertical meridians, to an eccentricity of 30 degrees. The coefficient of variation (CV) and intraclass correlation coefficient (ICC) were calculated for each measure.
On average the CV and ICC for repeatability was better than that for reproducibility (P0.75 to be excellent; [[gt]]0.40 but µ0.75 to be fair to good; µ0.40 to be poor agreement, all parameters measured showed excellent to good agreement except at the fovea, near retinal blood vessels, and towards the optic nerve. Repeatability and reproducibility for TRT, IRT, IS+ONLT, OS+RPET, IS/OSR and RNFLR was excellent to good; OS+RPET agreement was less reliable.
Thicker retinal sublayers are more reliably measured than thinner retinal sublayers. Measures of relative reflectivity are also reliable and may provide additional information about retinal structure that is not reflected in simple thickness measurements.
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