ONE OF the earliest investigations of the relationship between accommodation and convergence was that of Donders, who wrote: "The state of accommodation of the eyes corresponds to a definite convergence of the visual lines."1 He taught, however, that this "connection is not absolute and casual," but "that there is a certain degree of independence." One of Donders' pupils, Landolt,2 indicated even more forcibly the supposed independence of the two functions, as conceived by Donders:
The fact that we can see, distinctly and simultaneously, with both eyes an object situated at an invariable distance, in spite of glasses which necessitate a change in accommodation, is proof positive that the relation between the latter and convergence is not absolute; and in fact, equally easy to demonstrate, that such glasses cannot exceed certain degrees, proves that the independence of the two functions exists only within certain limits.
Donders coined the term
MORGAN MW. RELATIONSHIP BETWEEN ACCOMMODATION AND CONVERGENCE. AMA Arch Ophthalmol. 1952;47(6):745-759. doi:10.1001/archopht.1952.01700030764006