Abstract
Purpose :
Enlarged foveal avascular zone (FAZ) has been associated with lower visual acuity in diabetic patients. Accurate and automatic FAZ measurements could be a valuable tool in the management of diabetic macular edema. Here, we compare manual (MS) and automated segmentation (AS) FAZ tracings from 3 x 3mm optical coherence tomography angiography (OCTA) scans in healthy and diabetic macular edema (DME) patients.
Methods :
This IRB approved study prospectively collected OCTA images in patients evaluated in a tertiary care center where 43 eyes from 43 healthy individuals and 36 eyes from 36 DME patients were included. The FAZ superficial vascular plexus was traced by three masked, trained graders using ImageJ. The raw images were analyzed with the Advanced Retinal Imaging (ARI) network algorithm. All images were analyzed for perimeter, circularity, and area. Paired t-tests were used to compare the manual and automated methods.
Results :
For the healthy subjects, the FAZ area was 0.267 ± 0.149 mm2, and 0.244 ± 0.189 mm2 by MS and AS respectively (P=0.25). In DME patients, the FAZ area was 0.428 ± 0.222 mm2 and 0.347 ± 0.217 mm2 by MS and AS respectively (P=0.024). There was a statistically significant difference between the two methods for both perimeter and circularity in both cohorts of patients with AS underestimating perimeter (P=<0.001) and overestimating circularity (P=<0.001).
Conclusions :
Our study shows that while automatic FAZ segmentation is reliable in healthy subjects, the reliability is reduced when estimating FAZ area in patients with DME.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.