A method of optimising geometry of at least one semi-finished ophthalmic lens in a set of semi-finished ophthalmic lenses having a designated lens material, each of the semi-finished ophthalmic lenses in the set having an initially determined geometry including one of a plurality of base curves determined to allow manufacture of finished ophthalmic lenses for ophthalmic lens prescriptions, the method including: electronically providing prescription data indicative of ophthalmic lens prescriptions of a plurality of ophthalmic lens wearers; electronically determining a proportion of ones of the ophthalmic lens prescriptions that correspond to each one of the base curves of the semi-finished ophthalmic lenses in the set of semi-finished ophthalmic lenses; electronically providing manufacturing data indicative of constraints affecting manufacture of the set of semi-finished ophthalmic lenses, the constraints including at least volume of designated lens material of each of the semi-finished ophthalmic lenses in the set, as well as one or more of: a cost per different geometry of ones of the base curves of each of the semi-finished ophthalmic lenses in the set; a cost of the designated lens material; and a minimum thickness of the semi-finished ophthalmic lenses; electronically determining one or more final geometries of the at least one semi-finished ophthalmic lens in the set by optimising the initially determined geometry of each of the semi-finished ophthalmic lenses in the set using the proportion of said ones of the ophthalmic lens prescriptions that correspond to each one of the base curves of the semi-finished ophthalmic lenses in the set and the constraints, the one or more optimised final geometries of lenses are smaller in one or more of the parameters thickness, diameter, front curve radius, and back curve radius, per base curve to minimise use of lens material; and electronically outputting data indicative of the one or more final geometries. electronically providing prescription data indicative of ophthalmic lens prescriptions of a plurality of ophthalmic lens wearers; electronically determining a proportion of ones of the ophthalmic lens prescriptions that correspond to each one of the base curves of the semi-finished ophthalmic lenses in the set of semi-finished ophthalmic lenses; electronically providing manufacturing data indicative of constraints affecting manufacture of the set of semi-finished ophthalmic lenses, the constraints including at least volume of designated lens material of each of the semi-finished ophthalmic lenses in the set, as well as one or more of: a cost per different geometry of ones of the base curves of each of the semi-finished ophthalmic lenses in the set; a cost of the designated lens material; and a minimum thickness of the semi-finished ophthalmic lenses; electronically determining one or more final geometries of the at least one semi-finished ophthalmic lens in the set by optimising the initially determined geometry of each of the semi-finished ophthalmic lenses in the set using the proportion of said ones of the ophthalmic lens prescriptions that correspond to each one of the base curves of the semi-finished ophthalmic lenses in the set and the constraints, the one or more optimised final geometries of lenses are smaller in one or more of the parameters thickness, diameter, front curve radius, and back curve radius, per base curve to minimise use of lens material; and electronically outputting data indicative of the one or more final geometries. <EOS>