Methods The optometer is composed of singlechip, handle and LCD.The eyesight is examined by selecting exposure of random sample eye-chart mark E within direction keys on the handle.

采用微计算机控制视力检测仪，其由单片机、手和液晶显示屏构成，手有上下左右方等功能键，根据手上的按键选取随机出现视"E"的正确与否来检测视力。