Can be wall- mounted.
Number eye charts are an accurate and innovative way to test in multiple languages. Numbers are universal, unlike the Roman alphabet. PV Numbers are calibrated to Sloan letters, making them accurate and reliable for vision testing world wide. PV Numbers are also used for testing patients that cannot speak. These patients merely have to gesture what number they are seeing. Because of their calibration, PV Number results are equivalent to those from traditional vision tests such as Sloan charts.