Quantification of macular perfusion using optical coherence tomography angiography: repeatability and impact of an eye-tracking system

BACKGROUND: The aim of the study was to evaluate the impact of integration of the eye-tracking system (ET) on the repeatability of flow density measurements using optical coherence tomography (OCT) angiography. METHODS: 20 healthy subjects were included in this study. OCT-angiography was performed using RTVue XR Avanti (Optovue Inc., Fremont, California, USA). The macula was imaged using a 3 × 3 mm scan twice with and twice without activation of the ET. Flow density data of the macular in the superficial and deep OCT angiograms were extracted and analyzed. RESULTS: The difference between the flow density (whole en face) in the first session and second session with and without ET was statistically non-significant (with ET: superficial retinal OCT angiogram: p = 0.50; deep retinal OCT angiogram: p = 0.89; without ET: superficial retinal OCT angiogram: p = 0.81; deep retinal OCT angiogram: p = 0.24). There was no significant difference in the coefficients of repeatability for measurements with and without ET in the superficial retinal OCT angiogram (adjusted p-value = 0.176), whereas the difference was significant for the deep retinal OCT angiogram (adjusted p-value = 0.008). CONCLUSIONS: Integration of the ET improved the repeatability of flow density measurements in the deep OCT angiogram; this needs to be considered when evaluating the long-term changes of flow density and when comparing data of different studies and different devices.