[The determination of the maximal angular visual acuity and of the Vernier acuity (author's transl)].

In clinical diagnosis it is important to determine the maximal angular visual acuity by using for example the TNO Landolt C ring chart of Vos. The determination of the Vernier- or Nonius acuity is hardly of any clinical diagnostic significance because in several pathological conditions and in normal eyes the visual acuity is always three times higher than the angular visual acuity. Therefore this does not contribute to further differentiation.