OCTA Imaging Reveals Changes in Foveal Avascular Zone Shape in Prediabetes

Abstract

Purpose : OCT Angiography (OCTA) has shown changes in the foveal avascular zone (FAZ) in patients with diabetes, even without diabetic retinopathy. It is not as clear if prediabetic patients have similar FAZ microvascular alterations as compared to control subjects. The purpose of this observational clinical study is to determine if FAZ parameters are significantly different in people with prediabetes compared to healthy age-matched controls.

Methods : One eye from 7 control and 16 prediabetic participants with intact ocular health was included in this preliminary study of more than 60 participants. Following an ocular health examination to rule out pathology, the Zeiss Cirrus HD-OCT model 5000, OCTA Metrix 10.0, was used to image 3 x 3 mm of the superficial capillary plexus centered on the fovea. Images were analyzed using ImageJ software. Participants were age-matched and images were corrected for axial length. Outcome measures included the FAZ area, perimeter, circularity (perimeter smoothness), and roundness (axial symmetry). Statistical analysis was completed using Student’s t-test and coefficient of variation (CoV).

Results : Participant demographics and quantitative results are summarized in table 1. FAZ size of the prediabetes and control groups were not significantly different (P>0.05). Roundness of the FAZ was significantly increased in the prediabetic group (p=0.015, see figure 1), and similarly FAZ circularity showed a trend (p=0.17) towards increased circularity in the prediabetes group compared to controls. Averaged across both groups, CoV for FAZ shape factors of circularity and roundness was 17% and 5%, respectively, versus 40% for FAZ area, suggesting that FAZ shape parameters are more sensitive characteristics for detecting differences between these populations.

Conclusions : The results indicate FAZ shape, and not size, is significantly different in the prediabetes group compared to healthy controls. The lower CoV suggests FAZ shape parameters may be more sensitive measures of early changes in retinal vascular health in prediabetes. Future studies may support the use of OCTA imaging in identifying prediabetic changes.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Table 1. Average ± SEM and Coefficient of Variation (%), *p=0.015.

 

Figure 1. Example of the FAZ in a prediabetic (A) and control (B) subject. (C) OCTA image analysis revealed FAZ roundness was significantly increased in the prediabetic group compared to controls (p=0.015).