[Development of WY21A interference fringe visuometer and its clinical applications]

WY21A Interference Fringe Visuometer, based on Thomas Young's interference theory, uses grating to produce interference lamp-house. This compact, flexible machine could be applied to measure interference fringe visual acuity. Its clinical tryout shows that WY21A is suited for daily practice as it is able to give a fast, easy and reliable preoperative assessments and prediction of visual recovery for most age-related cataract patients.