Analysis of Radial Peripapillary Capillary Density in Patients with Bietti Crystalline Dystrophy by Optical Coherence Tomography Angiography

Objective We wanted to investigate the radial peripapillary capillary(RPC) network in patients with Bietti crystalline dystrophy(BCD).Methods We compared RPC densities in the disk and different peripapillary regions, obtained using optical coherence tomography angiography in 22 patients with BCD(37 eyes) and 22 healthy subjects(37 eyes). The BCD group was then divided into Stage 2 and Stage 3 subgroups based on Yuzawa staging,comparing the RPC densities of the two.Results The disk area RPC density was 38.8% ± 6.3% in the BCD group and 49.2% ± 6.1% in the control group(P < 0.001), and peripapillary region RPC density was significantly lower in the BCD group than in the control group(49.1% ± 4.7% and 54.1% ± 3.0%, respectively, P < 0.001). There were no significant RPC density differences between the tempo quadrant and inside disk of Stages 2 and 3 subgroups; the other areas showed a significantly lower RPC density in Stage 3 than in Stage 2 BCD.Conclusion The BCD group RPC density was significantly lower than the control group. The reduction of RPC density in the tempo quadrant occurred mainly in the Stage 1 BCD. In contrast, the reduction of RPC density in superior, inferior, and nasal quadrants occurred mainly in Stage 2.