Of the three layers of the eyeball, the innermost retinal layer is the beginning of how our nervous system forms images. Within the neural layer of the retina, two types of photoreceptors adjust rapidly to dim and bright lights. Rods are extremely sensitive to light, are more abundant in the periphery of the retina, and allow better vision during dim light, whereas cones react more quickly to bright light and allow us to perceive color vision (Tortora, G.J.& Derrickson, B.H. 2011). These key functions of the retina allow the ability to see contrast between images that appear, gray, black, or white. The ability to view images with high and low contrast can be the difference in knowing if an answer on a fill in the blank test has been marked or is still unanswered. Some conditions are able to be detected through the eyes, such as high blood pressure. By viewing the retina through an ophthalmoscope, physicians are able to detect health issues such as high blood pressure due to blood vessels which may be inflamed or damaged within the eye.

     In prior research studies, Vitamin A has been shown to improve vision. More recently Field, Williams & Butler conducted a research study where participants were asked to eat a piece of dark chocolate, perform a visual exam, and a cognitive test. The test was repeated using the same participants changing only the type of chocolate to white chocolate. When given the dark chocolate, results showed a significant improvement in visual contrasts and cognitive function. Flavonols are a subclass of the dietary compound flavonoids. Dark chocolate, specifically, contains more flavonols than white chocolate. The results can be explained by the abundance of flavonoids, which can be found in dark chocolate, grapes, wine, and tea. Researchers attributed the increase in visual acuity and cognitive function as a temporary increase in blood flow to the eyes and brain. .

Participants in the above study were young adults and generally do not have high blood pressure or cholesterol issues that an older adult may have. The importance of eye health is not generally a concern for young adults, however, retinal function is an imperative component in the visual pathway. Even without intentionally being health conscious of our eyes, drinking a glass of wine at dinner helps. Knowing the benefits of the cocoa phenol, flavonoid, it would suggest that students should be given a piece of dark chocolate before an exam.

Works Cited

Field D.T., Williams C.M., & Butler L.T. Consumption of Cocoa Flavanols Results in an Acute Improvement in Visual and Cognitive Functions. Physiology & Behavior. June 2011;103(3):255-60. Retrieved from http://www.nhiondemand.com/hsjarticle.

Tortora, G.J. & Derrickson, B.H. (2011). Principles of Anatomy & Physiology, 13th Edition. p 647-649