DETERMINING GLOBAL SHAPE PARAMETERS OF A CORNEA USING A TWO-FOLD FITTING FROM MEASUREMENT DATA TO AN ASPHERIC TORIC SURFACE MODEL

摘要

A method of determining global shape parameters of a cornea includes determining a height map of a cornea by: illuminating a cornea of an eye using a stimulator source having a plurality of point sources; capturing a reflected image of the plurality of point sources and determining a position of reflections of the respective plurality of point sources and deriving the height map of the cornea based on a position of the plurality of point sources and the position of the reflections of the respective plurality of point sources; fitting the height map as derived to a toric aspheric model to obtain a global fitting of the corneal surface to the toric aspheric model and; using the global fitting to determine one or more parameters related to an astigmatism of the cornea.