Intraobserver Repeatability of Automated versus Adjusted Optical Coherence Tomography Measurements in Patients with Neovascular Age-Related Macular Degeneration

Abstract

Aim: To assess the intraobserver repeatability of automated versusadjusted optical coherence tomography (OCT) measurements in patients with neovascular age-related macular degeneration (NVAMD). Methods: Ten eyes with NVAMD from 10 consecutive patients underwent two OCT measurements within 5 days by a single operator. Automated and adjusted central 1-mm foveal thickness and automated and adjusted total macular volume were measured in each study eye. The term ‘adjusted’ refers to manually corrected values, in which the interface landmarks for measurements are selected by the operator using Stratus® scan profiling and custom software. Bland-Altman method and bootstrap comparison of intraclass correlations (ICCs) were used for repeatability analysis. Results: Bland-Altman comparison did not reveal any statistically significant difference in any parameter, when results at first and second examination were compared (p > 0.05), indicating that the repeated measurements are similar. Further analysis was conducted using the bootstrap comparison of ICCs. The difference between adjusted and automated foveal thickness ICCs (r = 0.945 and 0.635, respectively) was significant (p = 0.031), indicating higher repeatability for adjusted foveal thickness. The ICCs for adjusted and automated total macular volume (r = 0.873 and 0.863, respectively) showed no statistically significant difference (p = 0.881). Conclusion: The repeatability of adjusted retinal thickness measurements, in which the errors of retinal boundary detection by OCT analysis software is corrected by the operator using scan profiling, is found to be higher than that of automated ones in this small group of NVAMD patients when performed by a single experienced operator.

Quality of the Threshold Algorithm in Age-Related Macular Degeneration: Stratus versus Cirrus OCT

“…The software version 3.0 of Cirrus OCT contains a built-in module to manually correct algorithm line failures. Although software options for the correction of Stratus OCT algorithm failures 19,20 are available, they are not built in. The data have to be exported, and they are not supported by the manufacturer of the Stratus OCT (Carl Zeiss Meditec, Inc.).…”

Duration of action of intravitreal ranibizumab and bevacizumab in exudative AMD eyes based on macular volume measurements

“…Second, we used automated CFPT and macular volume measurements obtained directly from OCT software rather than manually measuring these parameters from OCT images. Manual measurement of CFPT can allow the trained reader to eliminate software error in determining the location of topographic features such as the level of the retinal pigment epithelium or inner limiting membrane, but additional errors are introduced due to intraobserver and interobserver variation; additionally, a study comparing adjusted and automated measurements showed no overall difference between manually adjusted and automated macular volume measurement 23. Third, not all macular oedema is captured in the CFPT measurement; for this reason we also used automated macular volume measurements, which are accurate in the diagnosis of clinically significant macular oedema,24 for the curve fitting.…”

Inter-observer agreement for spectral- and time-domain optical coherence tomography image grading: a prospective study

“…This led to the creation of OCT reading centers where independent observers review OCT scans for defined pathologies and retinal thickness measurements. Data regarding OCT retinal thickness measurement reproducibility has been published previously [20][21][22][23][24][25][26][27].…”