Snellen Chart

The Snellen chart, named after the Dutch ophthalmologist Herman Snellen, has been used by clinicians for more than a century to assess a patient's ability to differentiate shapes and details of objects at a certain distance. The chart assists doctors in determining if their patients require eyeglasses or have vision issues. This chart uses a geometric scale, and the design has 11 lines of block letters and stylized letters on a 5×5 grid known as "optotypes." The first line contains large letters. As you progressed through each row, the number of letters and their size decreased until you reached the final row. The design of the chart is proven to be effective and easily recognized by everyone.