Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany.
JAMA Ophthalmol. 2019 Dec 1;137(12):1373-1379. doi: 10.1001/jamaophthalmol.2019.3731.
A recently reported randomized clinical trial suggested beneficial effects of vasodilating flavanols in dark chocolate on visual function without objective quantification of retinal perfusion.
To assess the effects of dark chocolate flavanols on subjective visual function and retinal perfusion objectively quantified on optical coherence tomography (OCT) angiography.
DESIGN, SETTING, AND PARTICIPANTS: This randomized, masked double-blind crossover clinical trial analyzed 22 healthy participants at the Department of Ophthalmology, Ludwig-Maximilians-University Munich, Germany, in July 2018. Analysis was intention to treat. Analysis began in July 2018.
Participants were randomized to consume 20 g of dark chocolate containing 400 mg of flavanols or 7.5 g of milk chocolate. Two hours later, visual function and retinal perfusion on OCT angiography were evaluated. Systemic blood pressure was measured to rule out artifacts on OCT angiography.
The primary end point was macular retinal perfusion quantified as vessel density on OCT angiography. The secondary end point was subjective visual function (Early Treatment Diabetic Retinopathy Study visual acuity, Pelli-Robson chart, and Mars chart contrast sensitivity).
All 22 participants (13 women [59.1%]; mean [SD] age, 27.3 [11.1] years) completed the trial. No relevant differences in baseline parameters between groups were identified. No change in the primary outcome measure, retinal perfusion, could be detected after consumption of dark vs milk chocolate (superficial plexus 48.0% vs 47.5%, treatment effect: -0.59 [95% CI, -2.68 to 1.50], P = .56; deep plexus 54.1% vs 54.0%, treatment effect: -1.14 [95% CI, -4.01 to 1.73], P = .42). No differences in changes in the secondary outcome parameters Early Treatment Diabetic Retinopathy Study visual acuity, Pelli-Robson chart, or Mars chart contrast sensitivity could be detected. Potentially confounding effects of changes in blood pressure were excluded.
In contrast to a previous similarly sized randomized clinical trial reporting beneficial effects on visual function, no short-term effects of flavanol-rich dark chocolate on automatically assessed retinal blood flow on OCT angiography or subjective visual function were observed in this study. As this small trial does not rule out the possibility of benefits, further trials with larger sample sizes would be needed to rule in or out possible long-term benefits confidently.
German Clinical Trials Register identifier: DRKS00015065.
最近的一项随机临床试验报告称，黑巧克力中的血管扩张性黄烷醇对视觉功能有益，但没有对视网膜灌注进行客观量化。
评估黑巧克力黄烷醇对主观视觉功能和视网膜灌注的影响，视网膜灌注通过光学相干断层扫描（OCT）血管造影进行客观量化。
设计、地点和参与者：这项随机、双盲、交叉临床试验在德国慕尼黑路德维希-马克西米利安大学眼科系进行，2018 年 7 月共纳入 22 名健康参与者。分析为意向治疗。分析于 2018 年 7 月开始。
参与者被随机分配食用含有 400 毫克黄烷醇的 20 克黑巧克力或 7.5 克牛奶巧克力。两小时后，评估 OCT 血管造影上的视觉功能和视网膜灌注。测量系统血压以排除 OCT 血管造影上的伪影。
主要终点是 OCT 血管造影上量化的黄斑视网膜灌注作为血管密度。次要终点是主观视觉功能（早期糖尿病视网膜病变研究视力、Pelli-Robson 图表和 Mars 图表对比敏感度）。
所有 22 名参与者（13 名女性[59.1%]；平均[标准差]年龄 27.3[11.1]岁）均完成了试验。组间无基线参数的显著差异。与食用黑巧克力相比，食用黑巧克力后，主要终点，视网膜灌注无变化（浅层丛 48.0%对 47.5%，治疗效果：-0.59[95%CI，-2.68 至 1.50]，P=0.56；深层丛 54.1%对 54.0%，治疗效果：-1.14[95%CI，-4.01 至 1.73]，P=0.42）。未检测到次要终点早期糖尿病视网膜病变研究视力、Pelli-Robson 图表或 Mars 图表对比敏感度的变化差异。排除了血压变化的潜在混杂影响。
与此前一项类似规模的随机临床试验报告视觉功能有益的结果相反，这项研究未观察到富含黄烷醇的黑巧克力对 OCT 血管造影上自动评估的视网膜血流或主观视觉功能的短期影响。由于这项小型试验不能排除有益的可能性，因此需要更大样本量的进一步试验来有信心地排除或确认可能的长期益处。
德国临床试验注册处标识符：DRKS00015065。
