Thin glass substrates are provided. Also provided are methods and apparatuses for the production thereof and provides a thin glass substrate of improved optical quality. The method includes, after the melting and before a hot forming process, adjusting the viscosity of the glass that is to be formed or has at least partially been formed is in a defined manner for the thin glass substrate to be obtained. The apparatus includes a device for melting, a device for hot forming, and also a device for defined adjustment of the viscosity of the glass to be formed into a thin glass substrate, and the device for defined adjustment of the viscosity of the glass to be formed into a thin glass substrate is arranged upstream of the device for hot forming.