[Causal mechanisms of intralental changes in hema lenses (author's transl)].

Changes in hema lenses can be divided into three groups: changes within the lens material, surface changes and a combination of the two. The various processes which bring about intralental changes are demonstrated with examples from daily practice. For accurate evaluation it is essential to make sections of the lenses. By doing so proof of the inhomogeneity of the lens material can be obtained.