A prediction engine comprising: one or more processors; wherein the prediction engine is configured to: obtain one or more pre-operative measurements of an eye for assisting a user to perform an intraocular lens, IOL, implantation in the eye; select, 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; evaluate 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; select a first prediction model from the first plurality of prediction model candidates based on the evaluating; calculate, using the selected first prediction model, a plurality of estimated post-operative MRSE values based on a set of available IOL powers and the one or more pre-operative measurements of the eye; determine, from the set of available IOL powers, a first IOL power corresponding to a first estimated post-operative MRSE value from the plurality of estimated post-operative MRSE values that matches a predetermined post-operative MRSE value; and provide, by the prediction engine, the determined first IOL power to the user to aid in selection of an IOL for implantation in the eye. one or more processors; wherein the prediction engine is configured to: obtain one or more pre-operative measurements of an eye for assisting a user to perform an intraocular lens, IOL, implantation in the eye; select, 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; evaluate 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; select a first prediction model from the first plurality of prediction model candidates based on the evaluating; calculate, using the selected first prediction model, a plurality of estimated post-operative MRSE values based on a set of available IOL powers and the one or more pre-operative measurements of the eye; determine, from the set of available IOL powers, a first IOL power corresponding to a first estimated post-operative MRSE value from the plurality of estimated post-operative MRSE values that matches a predetermined post-operative MRSE value; and provide, by the prediction engine, the determined first IOL power to the user to aid in selection of an IOL for implantation in the eye. obtain one or more pre-operative measurements of an eye for assisting a user to perform an intraocular lens, IOL, implantation in the eye; select, 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; evaluate 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; select a first prediction model from the first plurality of prediction model candidates based on the evaluating; calculate, using the selected first prediction model, a plurality of estimated post-operative MRSE values based on a set of available IOL powers and the one or more pre-operative measurements of the eye; determine, from the set of available IOL powers, a first IOL power corresponding to a first estimated post-operative MRSE value from the plurality of estimated post-operative MRSE values that matches a predetermined post-operative MRSE value; and provide, by the prediction engine, the determined first IOL power to the user to aid in selection of an IOL for implantation in the eye.