objective To monitor the cerebral hemodynamic index of presbyopia people using the Transcranial Doppler (TCD) and to explore the possible changes in cerebral blood supply of presbyopia people as a result of wearing Progressive Addition Lenses (PALs).

• 目的利用经颅多普勒超声技术,测定老视人群脑血流动力学指标,探讨配戴渐变多焦镜阅读时老视者脑血供的可能变化。