A method for performing multi-level eye registration comprising: obtaining a first initial reference eye image by a first diagnostic device and defining a reference coordinate system； obtaining a second eye image by a surgery device, said second eye image being obtained in a pre-surgery phase before the surgery has started； performing a first registration between said first eye image and said second eye image to obtain a first registration result； obtaining a third eye image by said surgery device, said third eye image being obtained after surgery has started； performing a second registration between said second eye image and said third eye image to obtain a second registration result； combining said first and second registration results to obtain a combined registration result to thereby obtain a registration between said initial reference eye image obtained by said diagnostic device and said third eye image obtained by said surgery device after surgery has started.
