B.L. Ullman, Origin and Development of Humanistic Script (Rome: Edizioni di storia e letteratura, 1960), pp. 14-15:
Why so much attention to the complaints of two aging men of the fourteenth century? Because they explain what happened. It may at first sight seem strange that it was the clear script of the fourteenth-century humanists like Petrarch and Coluccio rather than the crabbed Gothic of France, Germany, and England that was the first to be reformed. It is not always the institution or individual most in need of reforming that actually gets reformed first. At any rate, it would seem that the difficulties of Coluccio in particular had something to do with the reform, as we shall see. Eyeglasses had been invented, it is true, but they were neither widely used nor very satisfactory. So we may say that presbyopia started the reform of handwriting. Thanks to the improvement of eyeglasses in modern times, we determine or need for them and their strength by the ability to read the telephone book. In 1400 it was easier to change handwriting than to change glasses.