Abokyi S, Owusu-Mensah J, Osei K A
Department of Optometry, School of Allied Health Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana.
School of Optometry, Hong Kong Polytechnic University, Hong Kong.
Eye (Lond). 2017 Apr;31(4):615-619. doi: 10.1038/eye.2016.288. Epub 2016 Dec 16.
PurposeIt is purported that caffeine, an autonomic stimulant, affects visual performance. This study sought to assess whether caffeine intake was associated with changes in pupil size and/or amplitude of accommodation.Patients and methodsA double-masked, crossover study was conducted in 50 healthy subjects of age range 19 to 25 years. Subjects were randomized to treatments such that subjects consumed either 250 mg caffeine drink or vehicle on separate days. Amplitude of accommodation was measured by the push-up technique, and pupil size using a millimeter ruler fixed to a slit lamp biomicroscope in dim illumination (5 lux). Amplitude of accommodation and pupil size were taken at baseline, and at 30, 60 and 90 min time points post treatment. Repeated measures one-way ANOVA and paired t-test were used in analyzing data.ResultsAmplitude of accommodation and pupil size after caffeine intake were significantly greater than vehicle (P<0.001) at each time point. Consumption of the caffeine beverage was associated with significant increases in amplitude of accommodation and pupil size with time (P<0.001). Amplitude of accommodation rose from 12.4 (±2.2 D) at baseline to 15.8(±2.6 D) at 90 min. Similarly, pupil size increased from 3.4 (±0.4 mm) at baseline to 4.5 (±0.72 mm) at 90 min. Consumption of vehicle was not associated with increase in amplitude of accommodation or pupil size with time.ConclusionPupil size and accommodation are affected after ingestion of caffeine. This study suggests caffeine may have some influence on visual functions.
目的
据称，自主神经兴奋剂咖啡因会影响视觉表现。本研究旨在评估摄入咖啡因是否与瞳孔大小和/或调节幅度的变化有关。
患者与方法
对50名年龄在19至25岁之间的健康受试者进行了一项双盲交叉研究。受试者被随机分配接受治疗，使得他们在不同的日子分别饮用250毫克咖啡因饮料或对照剂。调节幅度通过上推法测量，瞳孔大小在昏暗照明（5勒克斯）下使用固定在裂隙灯显微镜上的毫米尺进行测量。在基线以及治疗后30、60和90分钟时间点测量调节幅度和瞳孔大小。使用重复测量单因素方差分析和配对t检验来分析数据。
结果
在每个时间点，摄入咖啡因后的调节幅度和瞳孔大小均显著大于对照剂（P<0.001）。饮用咖啡因饮料与调节幅度和瞳孔大小随时间的显著增加相关（P<0.001）。调节幅度从基线时的12.4（±2.2屈光度）升至90分钟时的15.8（±2.6屈光度）。同样，瞳孔大小从基线时的3.4（±0.4毫米）增加到90分钟时的4.5（±0.72毫米）。饮用对照剂与调节幅度或瞳孔大小随时间的增加无关。
结论
摄入咖啡因后瞳孔大小和调节受到影响。本研究表明咖啡因可能对视觉功能有一定影响。
