 A single-blinded crossover design will be used to assess possible effects of the dark or milk chocolate bars 72 cacao dark chocolate on visual performance and visual electrophysiological signals. Double-blinding experimenter unaware of the type of chocolate is not tenable due to the difference in coloration and aroma of the two chocolate bars and not likely to be a significant source of variability given the objective nature of the visual performance measures. Subjects will be tested in two one-hour sessions separated by at least 72 hours. Each subject will consume a different chocolate bar one-hour prior to testing with the order of bars dark vs. milk chocolate counter-balanced across subjects. Subjects will be asked to refrain from consuming coffee or caffeinated drinks on the day of testing and to consume the bar without milk or milk products which can lessen beneficial effects of dark chocolate. The subject will be presented the bar in its original wrapper but with the name masked by tape and shehe will be given a paper plate and napkins and asked to remove and return the wrapping to the research team members. The subject will be offered water during consumption of the bar which will take place in the research room. Insofar as many of the subjects will be in-house student volunteers, shehe will then remain in UIWRSO to study, work-study, finish clinical records, etc. for about 30 minutes. The patient will then undergo preliminary evaluation to prepare for the testing to commence at least 1 hour after chocolate bar consumption. This will include measurement of distant visual acuity followed by refraction to best visual acuity if the patient does not achieve 2020 in each eye with their habitual correction. Hence the patient will either wear their habitual correction or lenses in a trial frame to achieve best vision during testing. The patient will then be prepped for electro-diagnostic testing including visual-evoked potentials VEPs and electro-retinograms ERGs which objectively assess visual cortical and retinaoptic nerve function, respectively. VEPs will be recorded using the Diopsys system. The subject is seated comfortably before a reversing checkerboard display. The back of the head, forehead and temple will be wiped clean using an FDA approved non-abrasive cleaner. High and low contrast VEPs will be recorded from the back of the head using disposable skin electrodes with reference and ground electrodes at the forehead and temple, respectively. Cone specific color VEPs10 will also be recorded using the Diagnosys, LLC system. All VEPs will be recorded binocularly and not be initiated until one-hour following consumption of the chocolate bar. The Diopsys system will be used to record pattern ERGs optic nerve function, flicker ERGs cone function and the photopic negative response phNR; cone, bipolar cell and optic nerve function. Half of the subjects in control and experimental sessions will be tested with ERGs first and half with VEPs first to control for order effects. These FDA approved electro-diagnostic tests will be followed by letter chart measures of large and small CS Precision Vision, Inc.. Each subject will then be tested with the Innova Systems, Inc. computer controlled Cone Contrast Test which assesses red, green and blue cone CS as well as large and small blackwhite letter CS using an adaptive staircase like a hearing test to determine the lowest visible contrast and overall response time. As described in our previous study,7 each subject will undergo computer-based CS testing with and without verbal distraction during testing with order counterbalanced across subjects. The verbal distraction will be broadcast on a hands-free blue-tooth device to simulate an incoming phone call consisting of scripted questions to assess memory and cognitive performance while completing the CS tasks. Following these tests, the subject will be asked to perform a brief 10 minute WiiTM shooting game using the WiiTM zapper which is shaped like a small rifleno training is necessary. Two-way repeated measures ANOVA will be used to assess CS across distraction and chocolate bar conditions and post-hoc paired t-tests conducted to identify specific differences. Within subject ANOVAs and post-hoc t-test comparisons also will be used to assess amplitude and latency parameters of VEPs and ERGs across dark and milk chocolate conditions. 