The short answer is, well, yes. But only in the short-term.
A study published in June in JAMA Ophthalmology examined the vision-related effects of eating dark chocolate vs. those of eating milk chocolate. This study demonstrated that eating dark chocolate significantly improved small-letter contrast sensitivity (the ability to distinguish a letter against its background) in comparison to eating milk chocolate, within the span of two hours.*
Now that doesn’t mean that eating your favorite semisweet snack can become a substitute for your prescription eyeglasses, or that your cataracts will become clear again if you eat dark chocolate for breakfast. For your prescription or for treatment of cataracts you should still visit your local eye doctor or optician. But you can add the results of this sweet little study to the growing list of potential health benefits that accompany the consumption of dark chocolate.
Rabin JC, Karunathilake N, Patrizi K. Effects of Milk vs Dark Chocolate Consumption on Visual Acuity and Contrast Sensitivity Within 2 Hours: A Randomized Clinical Trial. JAMA Ophthalmol. 2018;136(6):678-681. doi:10.1001/jamaophthalmol.2018.0978