eye chart was introduced during the 1830s by doctors mentioned previously, the most effective chart to test visual acuity at the time was refined in 1862 by Dutch optometrist Herman Snellen. The conception of his chart began when Snellen became Donder's first assistant. Snellen worked closely with Dr. Donders as he determined vision impairments patients had by having them look at a chart on the wall. Donders eventually passed on his responsibilities to Snellen because he was very occupied with other disciplines of science like physiology. Because of Donders' fame and Snellen’s natural talent towards the field of ophthalmology, many doctors were enticed to visit in order to share ideas with them in Utrecht. As he worked closely through his practice, Snellen created his own chart that measured visual acuity. Snellen’s eye chart became the first of its type, hence it being the most scientifically reliable design in order to test vision distance in that time period. Snellen’s success within his charts was because they differed from past models that measured visual acuity. His chart varied the sizes of stimuli. Snellen’s eye chart opened the door to testing visual acuity, hence it became the global standard. The high demand for this chart was everywhere. Even japanese ophthalmologist Ema Tenko, who studied under Snellen, created an eye chart that was used in Japan. Because of the creation of eye charts, examinations like vision screening (roughly beginning in 1899) within schools took place in order to test children’s eyes. Optotype, another term that could define an eye chart, remains the most common exam in order to test standard vision. Procedure Charts display several rows of optotypes, which are standardized symbols for testing vision. Optotypes are usually letters, numbers, or geometric symbols. Each row of the chart depicts optotypes of a different size. Typically the largest optotypes are in the top row. The optotypes become progressively smaller towards the bottom of the chart. The person removes any glasses or contact lenses, and stands or sits a standardized distance from the chart (e.g., 20 feet for the Snellen chart). The person is then asked to identify the optotypes on the chart, starting with large rows and continuing to smaller rows until the optotypes cannot be reliably identified any more. The row in which the person can reliably identify symbols defines the visual acuity. One eye is tested at a time. Practically, this is accomplished