Eye Chart Measures 23 X 35.5 cm (9 X 14 in.) HOTV optotypes are great for testing preliterate children 3-4 years old. The child must be briefly taught each optotype before testing and shown the response key included. While testing, the child must simply point to the letter that they are seeing. This takes the guessing out of pediatric vision testing and make recording more accurate. HOTV chart also includes red and green bars for quick color vision screening while testing acuity vision.