Final answer:
The Snellen Chart is used for measuring visual acuity with Roman letters, the Tumbling E Chart is for those who cannot use the Roman alphabet, and the HOTV Chart is designed mainly for children.
Step-by-step explanation:
The Snellen Chart, the Tumbling E Chart, and the HOTV Chart are all tools used to evaluate visual acuity in an individual.
The Snellen Chart is the most common eye chart used to measure visual acuity. The chart presents a limited number of Roman letters in lines of decreasing size. The line with letters that subtend a 5-minute angle of an arc from 20 feet away indicates the smallest size that someone with normal acuity should be able to read from that distance.
The Tumbling E Chart is used particularly for individuals who cannot verbally communicate or are unfamiliar with the Roman alphabet. Instead of letters, it features the letter 'E' in different orientations, and the test subject indicates which direction the arms of the 'E' are pointing.
The HOTV Chart is used mainly for children who may not know their letters yet. It contains only four different characters - H, O, T and V - where the child is asked to identify the depicted letter, hence its name HOTV.