... measurement: The PD will be automatically calculated after measurement. Easy,one-hand control:All operations,including UP\Down,Right\Left,Forward\Backward ... and Start can be easily controlled with one hand through the control stick.Specification Vertex distance(VD) 0. ... .00D 0.12D/0.25D steps Axis 0~180°C(variable;1°C) Astigmatism identification -,+,± Pupil distance(PD) 45~85mm , ...