The study group consisted of 82 children aged 9 to 14 years with the following forms of myopia: progressive (37 cases), stable (22 cases), congenital stable (11 cases) and incipient (12 cases). During the period of progression in myopia, a significant increase was found in the 24-hour-excretion of acid mucopolysaccharides. In the patients with stable and congenital stable forms the excretion of acid mucopolysaccharides did not differ significantly from that in the control group of emmetropic and hypermetropic children. The results of electrophoresis on cellulose acetate and of the carbazol and orcinol reactions showed predominant excretion of A and C chondroitinsulphates in patients with myopia.