Rabin JC, et al. - Authors compared the short-term effects of consumption of dark chocolate with those of milk chocolate on visual acuity and large- and small-letter contrast sensitivity. Compared with a milk chocolate bar, contrast sensitivity and visual acuity were significantly higher 2 hours after consumption of a dark chocolate bar.

Methods

• Experts used a randomized, single-masked crossover design to assess short-term visual performance after consumption of a dark or a milk chocolate bar.
• Dark and milk chocolate was consumed by 30 participants without pathologic eye disease in separate sessions, and within-participant paired comparisons were used to assess outcomes.
• From June 25 to August 15, 2017, testing was conducted at the Rosenberg School of Optometry.
• They measured the visual acuity (in logMAR units) and large- and small-letter contrast sensitivity (in the log of the inverse of the minimum detectable contrast [logCS units]) 1.75 hours after consumption of dark and milk chocolate bars.

Results

• As per the data, among the 30 participants (9 men and 21 women; mean [SD] age, 26 [5] years), small-letter contrast sensitivity was significantly higher after consumption of dark chocolate (mean [SE], 1.45 [0.04] logCS) vs milk chocolate (mean [SE], 1.30 [0.05] logCS; mean improvement, 0.15 logCS [95% CI, 0.08-0.22 logCS];P < .001). Large-letter contrast sensitivity was slightly higher after consumption of dark chocolate (mean [SE], 2.05 [0.02] logCS) vs milk chocolate (mean [SE], 2.00 [0.02] logCS; mean improvement, 0.05 logCS [95% CI, 0.00-0.10 logCS];P=.07).
• Findings suggested that after consumption of dark chocolate (mean [SE], -0.22 [0.01] logMAR; visual acuity, approximately 20/12) and milk chocolate (mean [SE], -0.18 [0.01] logMAR; visual acuity, approximately 20/15; mean improvement, 0.04 logMAR [95% CI, 0.02-0.06 logMAR];P=.05), visual acuity improved slightly.
• Significant improvement after consumption of dark compared with milk chocolate were demonstrated by composite scores combining results from all tests (mean improvement, 0.20 log U [95% CI, 0.10-0.30 log U];P < .001).