Study of Foveal Avascular Zone Growth in Individuals With Mild Diabetic Retinopathy by Optical Coherence Tomography

PURPOSE: The purpose of this study was to investigate the association between foveal vessels and retinal thickness in individuals with diabetic retinopathy (DR) and control subjects, and to reveal foveal avascular zone (FAZ) growth in early individuals with DR. METHODS: The regions with a thickness less than 60 µm were marked from the intima thickness maps and named FAZ(Thic). The avascular zones extracted from the deep vascular plexus were designated as FAZ(Angi). The boundary of the two FAZ forms a ring region, which we called FAZ(Ring). The FAZ growth rate was defined as the ratio of the FAZ(Ring) area to the FAZ(Thic) area. Thirty healthy controls and 30 individuals with mild nonproliferative DR were recruited for this study. RESULTS: The FAZ(Thic) area in individuals with mild DR and control subjects showed similar distribution. The FAZ(Angi) area in individuals with mild DR are higher than that in control subjects on the whole, but there was no significant difference (P > 0.05). The FAZ(Ring) area in individuals with mild DR was significantly higher than that in control subjects (P < 0.001). However, there is still a small amount of overlap data between the two groups. For the FAZ growth rate, the individuals with mild DR were also significantly larger than the control subjects (P < 0.001). But there were no overlapping data between the two groups. CONCLUSIONS: The growth of FAZ in individuals with mild DR can be inferred by comparing FAZ(Angi) with FAZ(Thic). This method minimizes the impact of individual variations and helps researchers to understand the progression mechanism of DR more deeply.