1. A method of model-based determination of the biometry of eyes, based on optical coherence tomography (OCT), comprising illuminating the eye by a light source via a scanning unit, wherein a focus of a measuring light beam in the eye is movable or switchable laterally and/or axially by application of an adjusting device; detecting light components back-scattered from boundary surfaces and from tissue of the eye by a sensor via an interferometer; relaying information from the sensor to a control and evaluation unit; performing one or more scans having same or different scan patterns, same or different focus settings or a combination of the foregoing by application of the scanning unit, and receiving the scans by the sensor via the interferometer and relaying the one or more scans to the control and evaluation unit, which adapts a parametric eye model to create an adapted parametric eye model, which includes at least two boundary surfaces present in the eye; deriving biometric measured values from the adapted parametric eye model; and representing individual scans, all scans, the adapted parametric eye model or a combination thereof via a user interface.