HOTV optotypes easily identifiable, HOTV charts use four distinctly different yet equally recognizable letters. These letters can be identified by preliterate children, with the use of a response key. Also, featured on this HOTV vision test are both a red and a green stripe. These stripes can help as a screener for Color Vision. Also, the chart is useful for detecting early signs of amblyopia in children. This HOTV eye chart is great for school screenings for children 3-5 years old.