Questions on a Study on the Effects of Flavanol-Rich Dark Chocolate on Visual Function and Retinal Perfusion

To the Editor Siedlecki et al¹ compared dark (DC) and milk chocolate (MC) consumption on optical coherence tomography angiography (OCT-A), visual acuity (VA), and large-letter contrast sensitivity.¹ Their study was based on Rabin et al,² comparing DC with MC on VA, large-letter CS, and small-letter CS (SLCS). While both studies reported minimal VA and large-letter CS effects, Rabin et al² reported improved SLCS possibly because of flavanol-associated increased blood flow, suggesting that SLCS can identify visual acuity changes despite normal VA.³ The well-executed Siedlecki et al¹ study included double masking, baseline measures, and OCT-A. However, we raise questions and offer comments.