研究一种针对白内障患者的潜在视功能检测仪。采用透射式视力分辨率板并且使进入眼瞳成像光束足够细和有足够的光能量，以致能够通过白内障患者云雾状晶状体中的微小间隙在视网膜上成像，移动透射式视力分辨率板调焦可测出患者的视度在-7D～＋12D之间的潜在视力。进行了光学系统结构设计和理论计算，进行了实验和测试。实验测试结果表明，该系统出瞳位置光斑直径=0.094 mm，测得视力与传统测试方法测得视力相一致。通过该仪器对白内障患者手术前检测，可比较准确预测置换人工晶体手术后达到的视力水平，这对医生和患者都具有重要参考价值。

An instrument to measure the retinal potential visual acuity (PVA) of the patients, suffering from cataract, is studied. This instrument uses a transparent eye chart. With special optical system, the beam from the exit pupil of the instrument is thin enough to pass through the aperture of the opacity lens of eyes with cataract and forms image on the retina. The move of the eye chart makes it possible to measure the PVA of the patients with diopter -7～+12 m-1. The design of the configuration of the instrument and some theoretical calculation are finished, along with experiments and tests. The experiment shows that the diameter of the spot at the exit pupil is 0.094 mm, and the vision measured with potential vision meter (PVM) accords with that measured with traditional method. The PVA of the patients can be accurately measured with the instrument before the operation, which is important to both the doctors and the patients.