STUDIES WITH IMPEDANCE CYCLOGRAPHY ON HUMAN OCULAR ACCOMMODATION AT DIFFERENT AGES

In a previous paper (Swegmark &Olsson, 1968) a new method for the recording of accommodation was presented. This method, impedance cyclography (ICG), was shown to reflect ciliary muscle activity. This possibility of recording what has been called the physiological acconimodation leads to some interesting applications in the study of accommodation and its relation to presbyopia. There is evidence that lenticular sclerosis plays a major role in the continuous impairment of accommodative ability with increasing age, but the possibility that a decrease in the function of the ciliary muscle might be a contributing factor has been pointed out rather recently by Teramoto (1959). A related problem presenting more conflicting evidence is the question of whether the same activity of the ciliary muscle is required to produce a unit change of refraction at all ages, or if in older subjects more muscular activity is required than in young ones. The first mentioned view has been stressed by Gzdlstrand (1909) and the latter by Donders (1866). The evidence which can be put forward to support one or the other theory was recently reviewed by Alpern (1962), who pointed out that it is still too early to make a decisive choice between these two antagonistic views of presbyopia, The aim of the present study was to investigate the ciliary muscle activity