This study was conducted to investigate the size and shape of the foveal avascular zone (FAZ) determined by optical coherence tomography angiography (OCTA) and the relationship of the size and shape to the clinical findings in normal subjects. This was a cross-sectional study with seventy eyes of 70 volunteers. The size of the superficial FAZs were assessed by its area, length of perimeter, and Feret’s diameter, and the shape by the circularity, axial ratio, roundness, and solidity. The correlations between each parameter and the clinical findings were statistically determined. The coefficients of variation (CV) of the parameters of FAZ size were higher than that of the parameters of FAZ shape. The refractive error and axial length were significantly correlated with area-related factors. The central macular thickness (CMT) was significantly correlated with all parameters. Although the CMT was a critical factor that was significantly correlated with the size and shape characteristics of the FAZ, the shape might be a better factor for characterizing the FAZ than the size because of the low CV of shape-related factors and the characteristics are less affected by the other ocular factors.

Citation: Sonoda S, Sakamoto T, Yamashita T, et al. Effect of intravitreal triamcinolone acetonide or bevacizumab on choroidal thickness in eyes with diabetic macular edema. Invest Ophthalmol Vis Sci. 2014;55:3979-3985. PURPOSE.We evaluated the effect of intravitreal triamcinolone acetonide (IVTA) or intravitreal bevacizumab (IVB) on subfoveal choroidal thickness (SFCT) in eyes with diabetic macular edema (DME). METHODS.In this prospective, randomized, interventional comparative study, 51 DME eyes of 51 patients were randomized to receive either IVTA or IVB. The central macular thickness (CMT) and SFCT were determined by optical coherence tomography at 24 hours, 7 days, and 4, 8, and 12 weeks. The SFCT at 1500 and 3000 lm nasal or temporal to the central fovea also was measured. The values obtained before were compared to those obtained 12 weeks after the injections. RESULTS.The eyes were randomly assigned to the IVTA (25 eyes) and IVB (26 eyes) groups. The SFCT was reduced significantly in the IVTA group from 24 hours to 12 weeks. The average 6 SD of the SFCT expressed as the ratio to baseline thickness decreased to 94.8% 6 5.6% (P < 0.01) at 24 hours after IVTA and remained unchanged up to 12 weeks (91.8% 6 10.5%, P < 0.01, Wilcoxon signed-rank test). In the IVB group, no significant difference was found in the SFCT after IVB for 12 weeks. The CMT decreased significantly in both groups from 24 hours to 4 weeks; however, the decrease was not significant at 8 weeks or later in the IVB group.CONCLUSIONS. The decrease in choroidal thickness in eyes with DME after IVTA suggests that the choroidal pathology in diabetic retinopathy might be due to steroid-sensitive factors rather than vascular endothelial growth factor. (www.umin.ac.jp/ctr number, clinical trials number UMIN000009854.)

This study was performed to compare the area of the foveal avascular zone (FAZ-area) obtained by three optical coherence tomography angiography (OCTA) instruments. This was a cross-sectional, non-interventional study of twenty-seven healthy right eyes. The superficial and deep FAZ-area was measured manually with three OCTA instruments: Triton (Topcon), RS3000 (Nidek), and CIRRUS (Zeiss). The intra-rater, inter-rater, and inter-instrument correlation coefficients (CC) were assessed. The intra-rater and inter-rater CC were significantly high for the superficial and deep FAZ-areas (P < 0.001). The inter-instrument CC (95% confidence interval) for the superficial FAZ-area was 0.920 (0.803–0.965) for Triton vs RS3000, 0.899 (0.575–0.965) for RS3000 vs CIRRUS, and was 0.963 (0.913–0.983) for CIRRUS vs Triton (P < 0.001). For the deep FAZ-area, the inter-instrument CC was 0.813 (0.633–0.910) for Triton vs RS3000, 0.694 (0.369–0.857) for RS3000 vs CIRRUS, and 0.679 (0.153–0.872) for CIRRUS vs Triton (P < 0.001). The superficial FAZ-area (mm2) was 0.264 ± 0.071 with Triton, 0.278 ± 0.072 with RS3000 and 0.257 ± 0.066 with CIRRUS. For deep FAZ-area, it was 0.617 ± 0.175 with Triton, 0.646 ± 0.178 with RS3000 and 0.719 ± 0.175 with CIRRUS. The FAZ-area from these instruments was clinically interchangeable. However, the absolute values of FAZ-area are significantly different among them. These differences must be considered in comparing the FAZ-areas from different OCTA instruments.

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The symmetry of the RT between the upper and lower cells was high in the central and temporal-macular areas but not in the peripheral and nasal-macular areas. (www.umin.ac.jp/ctr number, UMIN000006040.).