Screening Vision in School-Age Children
Guidelines for Vision Screening in Missouri Schools
Screening Vision in School-Age Children
Visual Acuity
Visual acuity refers to the sharpness of one’s eyesight. The size of all letters in a row is smaller than the row above. Beside each row is a fraction. The top half of the fraction (numerator) stands for how many feet the person is standing from the chart (usually 20 feet). The bottom half of the fraction (denominator) shows how far away a person with normal visual acuity can stand from the chart and still read the symbol.
The 20/20 line is the standard for normal vision. A screening result of 20/100 means that the smallest line the person can read at 20 feet could be read by a person with normal vision at 100 feet.
- Numerator – distance from the subject to the chart, e.g., 20 feet
- Denominator – distance a person with normal vision can see the chart, e.g., 100 feet
- Example: 20/40 – At 20 feet, the eye sees at a 20 foot distance what a normal eye sees at
40 feet.