ABSTRACT
Purpose: To observe the effects of caffeine intake on vessel densities in macular and peripapillary regions and to analyze the correlations of vascular properties of these two interlinked regions in healthy volunteers using optical coherence tomography angiography (OCTA). Methods: In this prospective randomized, double?masked, placebo?controlled study, 120 participants were grouped into two groups: sixty subjects as a study group, which received caffeine and sixty subjects as a placebo group, which received a placebo. OCTA imaging was performed at baseline and 1 h after drug intake. Changes in macular and radial peripapillary capillary (RPC) vessel densities (VD) and foveal avascular zone (FAZ) parameters and correlation of these parameters were analyzed. Results: Baseline macular and RPC VD and FAZ parameters showed no significant difference between study and placebo groups (P > 0.05 for all). VD parameters in all segments of superficial and deep macular regions and peripapillary region showed a statistically significant decrease after caffeine intake (P < 0.001 for all). All macular superficial VD parameters showed a positive correlation with deep perifovea VD (P < 0.05 for all). Also, superficial perifovea VD was positively correlated with all deep macular VD parameters except deep fovea VD (P < 0.05 for all). Conclusion: We show that caffeine causes a decrease in macular and peripapillary vessel densities in healthy subjects, and correlations were observed between macular and peripapillary VD parameters. We believe that future studies are needed to support the effect of caffeine on peripapillary VD and the idea of using deep perifovea VD as the main parameter to estimate superficial macular parameters.
ABSTRACT
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.