1. An image-recognition method for assisting an ophthalmic examination instrument, comprising the following steps: using an ophthalmic examination instrument to generate a split-focusing image formed by a split-image focusing screen; setting a region-of-interest (ROI) around the split-focusing image; performing a pixel luminance addition processing on the ROI, wherein the pixel luminance addition processing increases a luminance contrast of all pixels in the ROI by adding luminance values of pixels surrounding each pixel to a luminance value of the surrounded pixel, so that all pixels in the ROI have increased luminance contrast; and performing a contrast correction on the ROI having increased luminance contrast, so that a luminance contrast between the split-focusing image and an area surrounding the split-focusing image in the ROI is further increased.