A method for intraocular lens selection performed by a prediction engine , the method comprising receiving , by one or more computing devices implementing the prediction engine, one or more pre-operative measurements of an eye for assisting a user to perform an intraocular lens, IOL, implantation in the eye; selecting , by the prediction engine from a plurality of historical IOL implantation records, a subset of historical IOL implantation records for evaluating a first plurality of prediction model candidates based at least on the one or more pre-operative measurements of the eye, wherein each of the first plurality of prediction model candidates estimates a post-operative manifest refraction in spherical equivalent, MRSE, based on a set of pre-operative eye measurements and an IOL power; evaluating , by the prediction engine, the first plurality of prediction model candidates based on deviations between estimated post-operative MRSEs produced by each of the first plurality of prediction model candidates using eye measurement data in the selected subset of historical IOL implantation records and actual post-operative MRSEs indicated in the selected subset of historical IOL implantation records, wherein the subset of IOL implantation records is selected to evaluate a second plurality of prediction model candidates, wherein each of the second plurality of prediction model candidates estimates an IOL power based on a set of pre-operative eye measurements and a desired post-operative MRSE; evaluating the second plurality of prediction model candidates based on deviations between estimated IOL powers produced by each of the second plurality of prediction model candidates using eye measurement data in the selected subset of historical IOL implantation records and actual IOL powers indicated in the selected subset of historical IOL implantation records; and selecting a second prediction model from the second plurality of prediction model candidates based on the evaluating. receiving , by one or more computing devices implementing the prediction engine, one or more pre-operative measurements of an eye for assisting a user to perform an intraocular lens, IOL, implantation in the eye; selecting , by the prediction engine from a plurality of historical IOL implantation records, a subset of historical IOL implantation records for evaluating a first plurality of prediction model candidates based at least on the one or more pre-operative measurements of the eye, wherein each of the first plurality of prediction model candidates estimates a post-operative manifest refraction in spherical equivalent, MRSE, based on a set of pre-operative eye measurements and an IOL power; evaluating , by the prediction engine, the first plurality of prediction model candidates based on deviations between estimated post-operative MRSEs produced by each of the first plurality of prediction model candidates using eye measurement data in the selected subset of historical IOL implantation records and actual post-operative MRSEs indicated in the selected subset of historical IOL implantation records, wherein the subset of IOL implantation records is selected to evaluate a second plurality of prediction model candidates, wherein each of the second plurality of prediction model candidates estimates an IOL power based on a set of pre-operative eye measurements and a desired post-operative MRSE; evaluating the second plurality of prediction model candidates based on deviations between estimated IOL powers produced by each of the second plurality of prediction model candidates using eye measurement data in the selected subset of historical IOL implantation records and actual IOL powers indicated in the selected subset of historical IOL implantation records; and selecting a second prediction model from the second plurality of prediction model candidates based on the evaluating. <EOS>