Ametropia, visual acuity and accommodative amplitude measuring apparatus for e.g. optician, has eye-piece graduated to give distance between cornea and secondary focus of lens, where distance is equal to glass-eye distance

摘要

The apparatus has a base, a principal lens and a slide holder (3) which is displaced over a trajectory and holds slides. A scale is provided whose graduations give the distance between an image and principal focus of the lens. An eye-piece (8) is graduated to give the distance between the cornea and the secondary focus of the lens. The latter distance is equal to the glass-eye distance for the measured refraction.