An apparatus for power conversion. The method includes the steps of: choosing a starting lens and defining a current lens equal to the starting lens; optimization, in worn conditions, of the current lens using as a target the astigmatism for which the wearer has been giving a prescription for far vision and the astigmatism for which the wearer has been given a prescription for near vision. The container may be deformable to conform to the shape of the allograft material as the container is shrink-fitted to the allograft. The middle portion is disposed along a rear portion of the enclosure and connected thereto and removably covers an opening defined through the rear portion of the enclosure through which the articles of memorabilia are inserted into and removed from the enclosure.