Abstract
Abstract: :
Purpose:To determine the accuracy of the Optical Coherence Tomograph (OCT, Zeiss Ophthalmics Systems, Dublin, CA) in a clinical setting. Methods:We retrospectively examined 224 macular thickness maps consisting of 1344 OCT scans. The scans were performed with the optical coherence tomograph in 64 patients (average age: 60±10, range: 29-80). We analyzed the individual scans for the occurrence of artifacts and curvefitting errors of the retinal thickness software. We categorized the errors according to "failure to detect retinal pigment epithelium (RPE) interface", "failure to detect internal limiting membrane (ILM) interface", "missing interface line", "slope error" and "small slope error". Results:We observed that 58% of the scans were free of error. In 4.3% of the scans we observed a failure to detect the RPE interface, while in 5.2% of the scans the ILM interface was not detected in a portion of the scan. In 37.6% of the scans, small errors of the interface slope were observed. These slope errors were usually only a few pixel wide. In only 1.1% of the scans, the entire interface line could not be detected by the OCT software. Conclusion:Optical Coherence Tomography is a method of generating high-resolution cross-sectional images of the retina and vitreous. The main use of OCT images is to guide treatment decisions and improve differential diagnosis. The software allows to generate secondary images consisting of interpolated retinal thickness maps. These thickness maps can be used to follow disease progression in diseases such as age-related macular degeneration, diabetic retinopathy and others. These thickness maps depend on accurate determination of retinal thickness in each underlying A-scan. The occurrence of errors suggests that it is imperative to review the individual scans of the OCT retinal thickness map. For the clinical use of the OCT the users need to ensure that the 6 scan lines comprising the retinal map are free of artifacts and curve fitting errors. A reading center for the evaluation of OCT scans can assist in the evaluation of the clinical images.
Keywords: 356 clinical (human) or epidemiologic studies: systems/equipment/techniques • 432 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 388 diabetic retinopathy